which two never misses to reign whenever the water freezes and both of them argue great store of little earthy dry bodies abounding in them which sweeping over all those that ly in their way and course must of necessity be mixed with such as give them admittance which water doth very easily And accordingly we see that when in the freezing of water the Ice grows any thing deep it either shrinks about the borders or at least lies very loose so as we cannot doubt but there is a free passage more of such subtile bodies to get still to the water and freez it deeper To his second argument we ask How he knows that Ice quantity for quantity is lighter then water For though of a Spunge that is ful of water it be easie to know what the spunge weighs and what the water that was soaked into it because we can part the one of them from the other and keep each apart to examine their weights yet to do the like between Ice and water if Ice be throughout full of air as of necessity it must be we believe impossible And therfore it may be lighter in the bulk then water by reason of the great pores caus'd in it through the shrinking up of the parts of water together which pores must then necessarily be fill'd with air and yet every part by it self in which no air is be heavier then so much water And by this it appears that his last argument grounded upon the the swiming of Ice in water has no more force then if he would prove that an iron or earthen dish were lighter and consequently more rare then water because it swims upon it which is an effect of the airs being contain'd in the belly of it as it is in Ice not a sign of the metals being more rare then water Wheras on the contrary side the proof is positive and clear for us For it cannot be denied but the mingling of the water with other bodies more dense then it must of necessity make the compound also the water it self become more dense then it was alone And accordingly we see that Ice half thaw'd for then much of the air is driven out and the water begins to fill the pores wherin the air resided before sinks to the bottom as an Iron dish with holes in it wherby the water might get into it would do And besides we see that water is more Diaphanous then Ice and Ice more consistent then water Therfore I hope we shall be excused if in this particular we be of a contrary opinion to this great personage But to return to the thrid of our discourse The same that passes here before us passes also in the Sky with Snow Hail Rain Wind. Which that we may the better understand let us consider how Winds are made for they have a main influence into all the rest When the Sun by some particular occurrent raises great multitudes of Atoms from some one place and they either by the attraction of the Sun or some other occasion take their course a certain way this motion of those atoms we call a wind which according to the continuance of the matter from whence these atoms rise endures a longer or a shorter time and goes a farther or a shorter way like a river or rather like those eruptions of waters which in the Northern parts of England they call Gypsies which break out at uncertain times and upon uncertain causes and flow likewise with an uncertain duration So these winds being composed of bodies in a determinate proportion heavier then the air run their course from their height to the ground where they are supported as water is by the floor of its channel whiles they perform their carreer that is till they be wasted either by the drawing of the Sun or by their sticking and incorporating into grosser bodies Some of these winds according to the complexion of the body out of which they are extracted are dry as those which come from barren mountains cover'd with snow others are moist as those that come out of marrishy or watry places others have other qualities as of heat or cold of wholsomness or unwholsomness and the like partly from the source and partly from the bodies they are mingled within their way Such then being the nature and origine of wind if a cold one meet in the air with that moist body wherof otherwise rain would have been made it changes that moist body into Snow or into Hail if a dry wind meet with a wet body it makes it more dry and so hinders the rain that was likely to be but if the wet body overcome the dry wind it brings the wind down along with it as we see when a showre of rain allays a great wind And that all this is so experience will in some particulars instruct us as well as reason from whence the rest may be evidently infer'd For we see that those who in imitation of nature would convert water into Ice take snow or ice mingle it with some active dry body that may force the cold parts of the snow from it and then they set the water in some fit vessel in the way that those little bodies are to take which by that means entring into it strait incorporate themselves therewith and of a suden convert it into ice Which process you may easily try by mingling Salt Armoniacke with snow but much more powerfully by setting the snow over the fire whiles the glass of water to be congealed stands in it after the manner of an egg in salt And thus fire it self though it be the enemy destroyer of all cold is made the instrument of freezing And the same reason holds in the cooling of wine with snow or ice when after it has been a competent time in the snow they whose charge it is use to give the vessel that contains the wine three or four turns in the snow so to mingle through the whole body of the wine the cold receiv'd first but in the outward parts of it and by pressing too make that without to have a more forcible ingression But the whole doctrin of Meteors is so amply so ingeniously and so exactly perform'd by that never-enough-praised Gentleman Mounsir Des Cartes in his Meteorological discourses as I should wrong my self and my Reader if I dwell any longer upon this subject And whose Physical discourses had they been divulged before I had entred upon this work I am perswaded would have excused the greatest part of my pains in delivering the nature of bodies It were a fault to pass from treating of Condensation without noting so ordinary an effect of it as is the joyning together parts of the same body or of divers bodies In which we see for the most part that the solide bodies which are to be joyn'd together are first either heated or moistned that is they are rarified and then they are left to cold
may be drawn to what height one pleases However the force which nature applies to maintain the continuity of quantity can have no limit seeing it is grounded upon contradiction And therefore Galileo was much mistaken when he thought to make an instrument wherby to discover the limits of this force We may then conclude that the breaking of the water must depend from the strength of other causes As for example when the gravity is so great by increasing the bulk of the water that it will either overcome the strength of the pipe or else make the sucker of the pump rather yield way to air then draw up so great a weight for which defects if remedies be found the art may surely be inlarged without end This is particular in a Syphon that when that arm of it which hangs out of the water is lower then the superficies of the water then it will run of it self after it is once set on running by sucking The reason whereof is because the weight which is in the water pendant is greater then the weight of the ascending water and therby supplyes the want of a continual suckeâ— But if the nose of that arm that hangs out of the water be put even with the water then the water will stand still in both pipes or arms of the Syphon after thy are filled with sucking But if by the running out of the water the outward pipe grow shorter then to reach as low as the superficies of the water in the fountain from whence it runs in this case the water in each arm of the Syphon will run back into the fountain Withall it is to be noted that though the arm which is out of the water be never so long yet if it reach not lower then the superficies of the fountain the over quantity and weight of the water there more then in the other arm helps it nothing to make it run out Which is because the declivity of the other arm over-recompences this overweight Not that the weight in the shorter pipe has so much force as the weight in the longer pipe but because it has more force then the greater weight exercises therin its running for the greatest part of its force tends another way then to the end of the pipe to wit perpendicularly towards the Centre and so is hindred from effect by the great sloping or little declivity of the pipe upon which it leans But some considering how the water in that longer arm of the Syphon is more in quantity than the water in the other arm of it wherat it runs out admire why the greater quantity of water doth noâ—d raw back the less into the cistern but suffers it self to be lifted up and drain'd away as if it run steeply downwards And they imagine that hence may be deduced that the parts of water in the cistern do not weigh as long as they are within the orb of their own body To whom we answer that they should consider how that to have the greater quantity of water in the longer arme of the Syphon which arm is immersed in the water of the cistern draw back into the cistern the water in the other arm of the Syphon that hangs out in the air it must both raise as much of the water of the cistern as its own bulk is above the level which at present the whole bulk of water has and withal at the same time pull up the water in the other arm Now 't is manifest that these two quantities of water together are heavier then the water in the sunk arm of the Syphon since one of them single is equal unto it And by consequence the more water in the sunk arm cannot weigh back the less water in the hanging arm since to do that it must at the same time weigh up over and above as much more in the cistern as it self weighs But turning the argument I say that if once the arm of the Syphon that is in the air be supposed to draw any water be it never so little out of the cistern whether occasioned by sucking or by whatever other means it follows that as much water as is drawn up above the level of the whole bulk in the cistern must needs press into the sunken arm from the next adjacent parts that is from the bottom to supply its emptying and as much must of it self press down from above according to its natural course when nothing violents it to rest in the place that the ascending water which is lower then it leavs at liberty for it to take possession of And then it cannot be doubted but that this descending water having all its weight in pressing down applied to drive up the rising water in the sunk arm of the Syphon the water in the other arm of the Syphon without having all its weight in ruÌ„ning out appli'd at the same time to draw up the same water in the sunk arm this single resistant must yield to their double mastering force And consequently the water in the arm of the Syphon that is in the air must needs draw the water that is the other immersed arm as long as the end of its pipe reaches lower then the level of the water in the cistern for so long it appears by what we have said it must needs be more weighty since part of the rising water in the sunk arm of the syphon is couÌ„ erpois'd by as much descending water in the cistern And thus 't is evident that out of this experiment it cannot be infer'd that parts of water do not weigh within the orb of their own whole but only that two equal parts of water in their own orb namely that which rises in the sunken arm and that which presses down from the whole bulke in the cistern are of equal weight and ballance one another So that never so little odds between the two counterpoysing parcels of water which are in the air must needs make the water run out at that end of the syphon where the overweight of water is The Attraction whose cause next to this is most manifest is that which is made by the force of heat or fire for we see that fire ever draws air to it so notably that if in a close room there be a good fire a man that stands at the door or window especially without shall hear such a noise that he will think there is a great wind within the chamber The reason of this attraction is that fire rarifying the air next it and withall spending it self perpetually causes the air and his own body mingled together to fly up through the chimney or by some other passage Whence it follows of necessity that the next body must succeed into the place of the body that is flown away The next body generally is air whose mobility and fluidity beyond all other bodies makes it of all others the fittest to be drawn and the more of it
of this subject but to enumerate the several specieses of Quantity according to that division which Logitians for more facilitie of discourse have made of it Namely these six Magnitude Place Motion Time Number and Weight Of which the two first are Permanent and lie still exposed to the pleasure of whoever has a mind to take a survey of them Which he may doe by measuring what parts they are divisible into how many ells feet inches a thing is long broad or deep how great a place is whether it be not biger or lesser then such another and by such considerations as these which all agree in this that they express the essence of those two Specieses of Quantity to consist in a Capacity of being divided into parts The two next Motion and Time though they be of a fleeting propriety yet 't is evident that in regard of their original and essential nature they are nothing else but a like divisibility into parts which is measured by passing over so great or so little distance and by years days hours minutes and the like Number we also see is of the same nature for it is divisible into so many determinate parts and is measured by unities or by lesser numbers so or so often contain'd in a proposed greater And the like is evident of Weight which is divisible into pounds ounces drams or grains and by them is measured So that looking over all the several specieses of Quantitie 't is evident our definition of it is a true one and expresses fully the essence of it when we say it is Divisibilitie or a Capacitie to be divided into parts and that no other notion whatever besides this reaches the nature of of it CHAP. III. Of Rarity and Density I Intend in this Chapter to look as far as I can into the nature and causes of the two first differences of Bodies which follow out of Quantity as it concurs with Substance to make a Body for the discovery of them and of the various proportions of them among themselves will be a great and important step in the journey we are going But the scarcity of our language is such in subjects remov'd from ordinary conversation though in others I think none is more copious or expressive as affords us not apt words of our own to express significantly such notions as I must busie my self about in this discourse therefore I will presume to borrow them from the Latine School where there is much adoe about them I would express the difference between bodies that under the same measures and outward bulk have a greater thinness and expansion or thickness and solidity one than another which terms or any I can find in English do not signifie fully those differences of Quantity which I intend here to declare therefore I will do it under the names of Rarity and Density the true meaning of which will appear by what we shall hereafter say 'T is evident to us that there are different sorts of Bodies of which though you take equal quantities in one regard yet they will be unequal in another Their magnitudes may be the same but their weights will be different or contrarywise their weights being equal their outward measures will not be so Take a pinte of Air and weigh it against a pinte of Water and you will see the ballance of the last go down amain but if you drive out the Aire by filling the pinte with Lead the other pinte in which the Water is will rise again as fast which if you pour out and fill that pinte with Quicksilver you will perceive the Lead to be much lighter and again you will find a pinte of Gold heavier then so much Mercury And in like manner if you take away of the heavy bodies till they agree in weight with the lighter they wil take up fill different proportions and parts of the measure that shall contain them But whence this effect arises is the difficulty we would lay open Our measures tel us their quantities are equal and reason assures us there cannot be two bodies in one and the same place therfore when we see a pinte of one thing outweighs a pinte of another that is thiner we must conclude there is more body compacted together in the heavy thing than in the light for else how could so little of a solid or dense thing be stretch'd out to take up so great room as we see in a basin of water that being rarified into smoke or air fills the whole chamber and again shrink back into so little room as when it returns into water or is contracted into ice But how this comprehension of more body in equal room is effected doth not a little trouble Philosophers To find a way that may carry us through these difficulties arising out of the Rarity and Density of Bodies let us do as Astronomers when they inquire the motions of the Spheres and Planets they take all the Phenomena or several appearances of them to our eyes and then attribute to them such Orbs courses and periods as may square and fit with every one of them and by supposing them they can exactly calculate all that will ever after happen to them in their motions So let us take into our consideration the chief properties of rare and dense bodies and then cast with our selvs to find out an hypothesis or supposition if it be possible that may agree with them all First it seems to us that dense bodies have their parts more close and compacted than others have that are more rare and subtile Secondly they are more heavy than rare ones Again the rare are more easily divided than the dense bodies for water oyl milk honey and such like substances will not only yield easily to any harder thing than shall make its way through them but they are so apt to division and to lose their continuity that their own weights will overcome and break it wheras in iron gold marble and such dense bodies a much greater weight and force is necessary to work that effect And indeed if we look wel into it we shall find that the rarer things are as divisible in a lesser Quantity as the more dense are in a greater and the same force will break the rarer thing into more and lesser parts than it will an equal one that is more dense Take a Stick of light wood of such a bigness that being a foot long you may break it with your hands and another of the same bigness but of a more heavy and compacted wood and you shall not break it though it be two foot long and with equal force you may break a loaf of bread into more and less parts then a lump of lead that is of the same bigness Which also will resist more to the division of Fire the subtillest divider that is then so much water will For the little atomes of fire which we shall discourse on hereafter
water run out in the same time To which I answer out of the same ground as before That because in running twice as fast there goes out double the water in every part of time and again every part of water goes a double space in the same part of time that is to say because double the celerity is drawn into double the water and double the water into doule the celerity therfore the present effect is to the former effect as the effect or quadrate of a double line drawn into into it self is to the effect or quadrate of half the said line drawn into it self And consequently the cause of the latter effect which is the weight then must be to the cause of the former effect that is to the former weight in the same proportion namely as the quadrate of a double line is to the quadrate of half that line And so you see the reason of what he by experience finds to be true Though I doubt not but when he shall set out the treatise which he has made on this subject the Reader will have better satisfaction In the mean while an experiment which Galileo delivers will confirm this doctrine He sayes that to make the same Pendant go twice as fast as it did or to make every undulation of it in half the time it did you must make the line at which it hangs double in Geometrical proportion to the line at which it hang'd before Whence it follows that the circle by which it goes is likewise in double Geometrical proportion And this being certain that celerity to celerity has the proportion of force which weight has to weight 't is evident that as in one case there must be weight in Geometrical proportion so in theother case where only celerity makes the variance the celerity must be in double Geometrical proportion according as Galileo finds it by experience But to return to our main intent there is to be further noted that If the subject strucken be of a proportionate cessibility it seems to dull and deaden the stroke wheras if the thing strucken be hard the stroke seems to lose no force but to work a greater effect Though indeed the truth be that in both cases the effects are equal but diverse according to the natures of the things that are strucken for no force that once is in nature can be lost but must have its adequate effect one way or other Let us then first suppose the body strucken to be a hard body of no exceeding bigness in which case if the stroke light perpendicularly upon it it will carry such a body before it But if the body be too great and have its parts so conjoyn'd that they are weaker then the stroke in this case the stroke drives one part before it and so breaks it from the rest But lastly if the parts of the strucken body be so easily cessible as without difficulty the stroke can divide them then it enters into such a body till it has spent its force So that now making up our account we see that an equal effect proceeds from an equal force in all the three cases though in themselves they be far different But we are apt to account that effect greater which is more considerable to us by the profit or damage it brings us And therefore we usually say that the blow which shakes a wall or beats it down and kills men with the stones it scatters abroad hath a greater effect then that which penetrates far into a mud wall and doth little harm for that innocuousness of the effect makes that although in it self it be as great as the other yet 't is little observ'd or consider'd This discourse draws on another which is to declare how motion ceases And to sum that up in short we say that When motion comes to rest it decreases and passes through all the degrees of celerity and tardity that are between rest and the height of that motion which so declines and that in the proportion of the odd numbers as we declared above it encreas'd The reason is clear because that which makes a motion cease is the resistance it findes which resistance is an action of a mover that moves something against the body moved or something equivalent to such an action wherefore it must follow the laws that are common to all motions of which kind those two are that we have expressed in this conclusion Now that resistance is a countermotion or equivalent to one is plain by this that any body which is pressed must needs press again on the body that presses it wherefore the cause that hinders such a body from yielding is a force moving that body against the body which presses it The particulars of all which we shall more at large declare where we speak of the action and reaction of particular bodies CHAP. X. Of Gravity and Levity and of Local Motion commonly term'd Natural IT is now time to consider that distinction of motions which is so famous in Aristotle to wit that some motions are natural others violent and to determine what may be signified by these terms For seeing we have said that no body hath a natural intrinsecal inclination to any place to which 't is able to move it self we must needs conclude that the motion of every body follows the percussion of extrinsecal Agents It seems therefore impossible that any body should have any motion natural to it self and if there be none natural there can be none violent and so this distinction will vanish to nothing But on the otherside Living creatures manifestly shew natural motions having natural instruments to perform certain motions wherefore such motions must of necessity be natural to them But these are not the motions we are to speak of for Aristotles division is common to all bodies or at the least to all those we converse with and particularly to those which are call'd heavy and light which two terms pass through all the bodies we have notice of Therefore proceeding on our grounds before lay'd to wit that no body can be moved of it self we may determine those motions to be natural to bodies which have constant causes or percutients to make them always in such bodies and those violent which are contrary to such natural motions Which being suppos'd we much search out the causes that so constantly make some bodies descend towards the center or the middle of the earth others to rise and go from the center by which the world is subject to those restless motions that keep all things in perpetual flux in this changing sphere of action and passion Let us then begin with considering what effects the Sun which is a constant and perpetual cause works on inferiour bodies by his being regularly sometimes present and sometimes absent Observe in a pot of water hanging over a fire how the heat makes some parts of the water ascend and others to supply the room
as positive gravity or levity but that their course upwards or downwards happens to them by the order of nature which by outward causes gives them an impulse one of these wayes without which they would rest quietly wherever they are as being of themselvs indifferent to any motion But because our words express our notions and they are fram'd according to what appears to us when we observe any body to descend constantly towards our earth we call it heavie and if it move contrarywise we call it light But we must take heed of considering such gravity and levity as if they were Entities that work such effects since upon examination it appears that these words are but short expressions of the effects themselves the causes whereof the vulgar of mankind who impose names to things do not consider but leave that work to Philosophers to examine whiles they onely observe what they see done and agree upon words to express that Which words neither will in all circumstances always agree to the same thing for as cork descends in aire and ascends in water so also will any other body descend if it lights among others more rare then it self and will ascend if it lights among others that are more dense then it And we term Bodies light and heavy only according to the course which we usually see them take Now proceeding further on and considering how there are various degrees of density or gravity it were irrational to conceive that all bodies should descend at the same rate and keep equal pace with one another in their journey downwards For as two knives whereof one hath a keener edge then the other being press'd with equal strength into like yielding matter the sharper will cut deeper then the other so if of two bodies one be more dense then the others that which is so will cut the air more powerfully and descend faster then the other for in this case density may be compared to the kniefs edge since in it consists the power of dividing as we have heretofore determin'd And therefore the pressing them downwards by the descending atomes being equal in both or peradventure greater in the more dense body as anon we shall have occasion to touch and there being no other cause to determine them that way the effect of division must be the greater where the divider is the more powerful Which the more dense body is and therefore cuts more strongly through the resistance of the air and consequently passes more swiftly that way 't is determin'd to move I do not mean that the velocities of their descent shall be in the same proportion to one another as their densities are for besides their density those other considerations which we have discours'd of above when we examin'd the causes of velocity in motion must likewise be ballanced And out of the comparisons of all them not out of the consideration of any one alone results the differences of their velocities nor that neither but in as much as concerns the consideration of the moveables for to make the calculation exact the Medium must likewise be considered as by and by we shall declare For since the motion depends of all them together though there should be difference between the moveables in regard of one only and that the rest were equal yet the proportion of the difference of their motions must not follow the proportion of their difference in that one regard because their difference consider'd single in that regard will have one proportion and with the addition of the other considerations though alike in both to their difference in this they will have another As for example reckon the density of one moveable to be double the density of another moveable so that in that regard it has two degrees of power to descend whereas the other has but one suppose then the other causes of thier descent to be alike in both and reckon them all three and then joyn these three to the one which is caused by the density in one of the moveables as likewise to the two which is caused by the density in the other moveable and you will find that thus altogether their difference of power to descend is no longer in a double proportion as it would be if nothing but their density were considered but is in the proportion of five to four But after we have consider'd all that concerns the moveables we are then to cast an eye upon the Medium they are to move in and we shall find the addition of that decreases the proportion of their difference exceedingly more according to the cessibility of the Medium Which if it be Air the great disproportion of its weight to the weight of those bodies which men use to take in making experiences of their descent in that yeelding Medium will cause their difference of velocity in descending to be hardly perceptible Even as the difference of a sharp or dull knife which is easily perceiv'd in cutting of flesh or bread is not to be distinguish'd in dividing of water or oyl And likewise in Weights a pound and a scruple will bear down a dram in no sensible proportion of velocity more then a pound alone would do and yet put a pound in that scale in stead of the dram and then the difference of the scruple will be very notable So then those bodies whose difference of descending in water is very sensible because of the greater proportion of weight in water to the bodies that descend in it will yield no sensible difference of velocity when they descend in air by reason of the great disproportion of weight between air and the bodies that descend in it The reason of this will clearly shew it self in abstracted proportions Thus Suppose air to have one degree of density and water to have 400 then let the moveable A. have 410 degrees of density and the moveable B. have 500. Now compare their motion to one another in the several mediums of air and water The exuperance of the density of A. to water is 10 degrees but the exuperance of B. to the same water is 100 degrees so that B. must have in water swifter then A in the proportion of 103 to ten that is of 10 to one Then let us compare the exuperance of the two moveables over air A is 409 times more dense then air but B is 499 times more dense then it by which account the motion of B. must be in that medium swifter then the motion of A in the proportion of 499 to 409 that is about 50 to 41 which to avoid fractions we may account as 10 to 8. But in water they exceed one another as 10 to one so that their difference of velocity must be scarce perceptible in air in respect of what it is in water Out of all which discourse I only infer in common that a greater velocity in motion will follow the greater density of the moveable without determining
notable degree as for example to water makes then a great difference of a heavy bodies gravitation in it and accordingly we see a great difference between heavy bodies descending in water and in air though between two kinds of air none is to be observ'd their difference is so smal in respect of the density of the body that descends in them And therfore since an assured and certain difference in circumstances makes no sensible inequality in the affect we cannot expect any from such circumstances as we may reasonably doubt whether there be any inequality among them or no. Besides that if in any of the proposed cases a heavy body should gravitate more and be heavier one time than another yet by weighing it we could not discern it since the counterpoise which is to determine its weight must likewise be in the same proportion heavier then it was And besides weighing no other means remains to discover its greater graviation but to compare it to Time in its descent and I believe that in all such distances as we can try it in its inequalities will be no whit less difficult to be observ'd that way then any other Lastly to bend our discourse particularly to that instance of the objection where it is conceiv'd that if gravity or descending downwards of bodies proceeded from atoms striking on them as they move downwards it would follow that a stone or other dense body lying under shelter of a thick hard and impenetrable adamantine rock would have no impulse downwards and consequently would not weigh there We may note that no body whatever compacted by physical causes and agents can be so dense and imporous but that such atoms as these we speak of must be in them and in every part of them and every where pass through and through them as water doth through a sieve or through a spunge and this universal maxime must extend as far as the Sun or any other heat communicating with the Sun reaches and is found The reason whereof is because these atoms are no other thing but such extreme little bodies as are resolved by heat out of the main stock of those massie bodies upon which the Sun and heat do work Now then it being certain out of what we have heretofore said that all mixt bodies have their temper and consistence and generation from the mingling of fire with the rest of the Elements that compose them and from the concoction or digestion which fire makes in those bodies 't is evident that no mixt body whatever nor any sensible part of a mixt body can be void of pores capable of such atoms or be without such atoms passing through those pores which atoms by mediation of the air that likewise hath its share in such pores must have communication with the rest of the great sea of air and with the motions that pass in it And consequently in all and every sensible part of any such extreme dense and pretended inpenetrable body to the notice wherof we can arrive this percussion of atoms must be found and they will have no difficulty in running through nor by means of it in striking any other body lying under the shelter of it and thus both in from that hard body there must be stil an uninterrupted continuation of gravity or of descending towards the centre To which we may adde that the stone or dense body cannot lie so close to the rock that covers it but that some air must be between for if nothing were between they would be united and become one continued body and in that air which is a Creek of the great Ocean of air spread over the world that is every where bestrew'd with moving atoms and which is continually fed like a running stream with new air that drives on the air it overtakes no doubt but there are descending atoms as well as in all the rest of its main body and these descending atoms meeting with the stone must needs give some stroke upon it and that stroke be it never so little cannot chuse but work some effect in making the stone remove a little that way they go and that motion wherby the space is inlarg'd between the stone and the shelt'ring rock must draw in a greater quantity of air and atoms to strike upon it And thus by little and little the stone passes through all the degrees of tardity by which a descending body parts from rest which is by so much the more speedily done by how much the body is more eminent in density But this difference of time in regard of the atoms strokes only and abstracting from the bodies density will be insensible to us seeing as we have said no more is required of them but to give a determination downwards And out of this we clearly see the reason why the same atoms striking upon one body lying on the water make it sink and upon another they do not As for example if you lay upon the superficies of some water a piece of iron and a piece of cork of equal bigness and of the same figure the iron will be beaten down to the bottom and the cork will float at the top The reason wherof is the different proportions of the comparison of their densities with the density of water for as we have said the efficacy and force of descending is to be measured by that So then the strokes of the atoms being more efficatious upon water then upon cork because the density of water is greater then the density of cork considering the abundance of air that is harbor'd in the large pores of it it followes that the atoms will make the water go down more forcibly then they will cork But the density of iron exceeding the density of water the same strokes will make the iron descend faster then the water and consequently the iron must sink in the water and the cork will swim upon it And this same is the cause why if a piece of cork be held by force at the bottom of the water it will rise up to the top as soon as the violence is taken away that kept it down for the atoms strokes having more force on the water then on the cork they make the water sink and slide under it first a little thin plate of water and then another a little thicker and so by degrees more and more till it hath lifted the cork quite up to the top Fifthly it may be objected that these atoms do not descend always perpendicularly but somtimes slopingly and in that case if their strokes be the cause of dense bodies moving they should move sloping and not downward Now that these atoms descend somtimes slopingly is evident as when for example they meet with a stream of water or with a strong wind or even with any other little motion of the air such as carries feathers up and down hither and thither which must needs waft the atoms in some measure along
with them their way Seeing then that such a gentle motion of the air is able to put a feather out of its way notwithstanding the percussions of the atoms upon it why shall it not likewise put a piece of iron out of its way downwards since the iron hath nothing from the atoms but a determination to its way But much more why should not a strong wind or a currant of water do it since the atoms themselv's that give the iron its determination must needs be hurried along with them To this we answer that we must consider how any wind or water which runs in that sort is it self originally full of such atoms which continually and every where press into and cut through it in pursuing their constant perpetual course of descending in such sort as we shewed in their running through any hard rock or other densest body And these atoms make the wind or water primarily tend downwards though other accidental causes impel them secundarily to a sloping motion And still their primary natural motion will be in truth strongest though their not having scope to obey that but having enough to obey the violent motion makes this become the more observeable Which appears evidently out of this that if there be a hole in the bottome of the pipe that conveys water slopingly be the pipe never so long and consequently the sloping motion never so forcible yet the water will run out at that hole to obey its more powerful impulse to the centrewards rather then continue the violent motion in which it had arrived to a great degree of celerity Which being so 't is easie to conceive that the atoms in the wind or water which move perpendicularly downwards will still continue the irons motion downwards notwithstanding the Mediums sloping motion since the prevailing force determines both the iron and the Medium downward and the iron has a superproportion of density to cut its way according as the prevalent motion determines it But if the descending atoms be in part carried along down the stream by the current of wind or water yet still the current brings with it new atoms into the place of those that are carried away and these atoms in every point or place wherever they are of themselvs tend perpendicularly downwards though they are forced from the compleat effect of their tendance by the violence of the current so that in this case they are moved by a declining motion compounded of their own natural motion and the force one with which the stream carries them Now then if a dense body fall into such a current where these different motions give their several impulses it will be carried in such sort as we say of the atoms but in another proportion not in a perpendicular but in a mixt declining line compounded of the several impulses which the atoms and current give it in which also 't is to be remembred how the current gives an impulse downwards as well as sloping and peradventure the strongest downwards and the declination will be more or less according as the violent impulse prevails more or less against the natural motion But this is not all that is to be consider'd in estimating the declination of a dense bodies motion when it is sinking in a current of wind or water You must remember that the dense body it self has a particular virtue of its own namely its density by which it receivs and prosecutes more fully its determination downwards and therfore the force of that body in cutting its way through the Medium is also to be considered in this case as well as above calculating its declining from the perpendicular and out of all these causes will result a middle declination compounded of the motion of the water or wind both ways and of its own motion by the perpendicular line And since of these three causes of a dense bodies motion it s own virtue in prosecuting by its density the determination it requires is the most efficacious by much after it has once receiv'd a determination from without its declination will be but little if it be very dense and heavy But if it recede much from density as so have some near proportion to the density of the Medium the declination will be great And in a word according as the body is heavier or lighter the declination will be more or less in the some current though not exactly according to the proportion of the diminishing of its density as long as there is a superproportion of its density to the Medium since such a superproportion as we have declared heretofore makes the Mediums operation upon the dense body scarce considerable And hence you see why a stone or piece of iron is not carried out of its way as well as a feather because the stones motion downwards is greater and stronger then the motion of a feather downwards And by consequence the force that can turn a feather from its course downwards is not able to deturn a stone And if it be repli'd that it may be so order'd that the stone shall have no motion before it be in the stream of a river and notwithstanding it will still move downwards we may answer that considering the little declivity of the bed of such a stream the strongest motion of the parts of the stream must necessiariy be downwards and consequently they will beat the stone downwards And if they do not the like to a feather or other light body 't is because other parts of the stream get under the light body and beat it upwards which they have not power enough to do to the stone Sixthly it may be objected that if Elements do not weigh in their own Spheres then their gravity and descending must proceed from some other cause and not from this percussion of the atoms we attribute to it which percussion we have determin'd goes through all bodies whatever and beats upon every sensible part of them But that Elements weigh not in their own Spheres appears out of the experience of a Syphon for though one leg of a Syphon be sunk never so much deeper into the body of the water then the other leg reaches below the superficies of the water nevertheless if once the outward leg become full of water it will draw it out of the other longer leg Which it should not do if the parts of water that are comprised within their whole bulk did weigh since the bulk of water is much greater in the sunk leg then in the other and therfore these should rather draw back the other water into the Cistern then be themselves drawn out of it into the air To this we answer that 't is evident the Elements do weigh in their own Spheres at least as far as we can reach to their Spheres for we see that a ball once stuff'd hard with air is heavier then an empty one Again more water would not be heavier then less if the inward
parts of it did not weigh and if a hole were dig'd in the bottome of the Sea the water would not run into and fill it if it did not gravitate over it Lastly there are those who undertake to distinguish in a deep water the divers weights which several parts of it have as they grow still heavier and heavier towards the bottom and they are so cunning in this art that they profess to make instruments which by their equality of weight to a determinate part of the water shall stand just in that part and neither rise or fall higher or lower but if it be put lower it shall ascend to its exact equally weighing Orbe of the water and if it be put higher it shall descend till it comes to rest precisely in that place Whence 't is evident that parts of water do weigh within the bulk of their main body and of the like we have no reason to doubt in the other two weighty Elements As for the opposition of the Syphon we refer that point to where we shall have occasion to declare the nature of that engine on set purpose And there we shall shew that it could not succeed in its operation unless the parts of water did gravitate in their main bulk into which one leg of the Syphon is sunk Lastly it may be objected that if there were such a course of atoms as we say and their strokes were the cause of so notable an effect as the gravity of heavy bodies we should feel it palpably in our own bodies which experience shews us we do not To this we answer first that there is no necessity we should feel this course of atoms since by their subtilty they penetrate all bodies and consequently do not give such strokes as are sensible Secondly if we consider that dusts and straws and feathers light upon us without causing any sense in us much more we may conceive that atoms which are infinitely more subtile and light cannot cause in us any feeling of them Thirdly we see that what is continual with us and mingled in all things doth not make us take any especial notice of it and this is the cause of the smiting of atoms Nevertheless peradventure we feel them in truth as often as we feel hot and cold weather and in all Catars or other such changes which as it were sink into our body without our perceiving any sensible cause of them for no question these atomes are the immediate causes of all good and bad qualities in the air Lastly when we consider that we cannot long together hold out our arm at length or our foot from the ground and reflect upon such like impotencies of our resisting the gravity of our own body we cannot doubt but that in these cases we feel the effect of these atomes working upon those parts though we cannot by our sense discern immediately that these are the causes of it But now it is time to draw our Reader out of a difficulty which may peradventure have perplext him in the greatest part of what he hath hitherto gone over In our investigation of the Elements we took for a principle thereto that gravity is sometimes more sometimes less then the density of the body in which it is but in our explication of rarity and density and again in our explication of gravity we seem to put that gravity and density is all one This thorn I apprehend may in all this distance have put some to pain but it was impossible for me to remedy it because I had not yet deliver'd the manner of gravitation Here then I will do my best to asswage their grief by reconciling these appearing repugnancies We are therefore to consider that density in it self signifies a difficulty to have the parts of its subject separated one from another and that gravity likewise in it self signifies a quality by which a heavy body descends towards the center or which is consequent thereto a force to make another body descend Now this power we have shew'd belong to density so far forth as a dense body being strucken by another doth not yield by suffering its parts to be divided but with its whole bulk strikes the next before it and divides it if it be more divisible then it self is So that you see Density has the name of Density in consideration of a passive quality or rather of an impassibility which it hath and the same density is call'd Gravity in respect of an active quality it has which follows this impassibility And both of them are estimated by the different respects which the same body or subject in which they are has to different bodies that are the terms whereto it is compared for the active quality or Gravity of a dense body is esteem'd by its respect to the body it strikes upon whereas its Density includes a respect singly to the body that strikes it Now 't is no wonder that this change of comparison works a disparity in the denominations and that thereby the same body may be conceiv'd to be more or less impartible then it is active or heavy A for example let us of a dense Element take any one least part which must of necessity be in its own nature and kind absolutely impartible and yet 't is evident that the gravity of this part must be exceeding little by reason of the littleness of its quantity so that thus you see an extremity of the effect of density joyn'd together in one body by the accident of its littleness with a contrary extremity of the effect of gravity or rather with the want of it each of them within the limits of the same species In like manner it happens that the same body in one circumstance is more weighty in another or rather in the contrary is more partible So water in a Pail because 't is thereby â—hinder'd from spreading abroad has the effect of gravity predominating in it but if it be pour'd out it has the effect of partibility more And thus it happens that meerly by the gradation of rarity and density one dense body may be apt out of the general course of natural causes to be more divisible then to be a divider though according to the nature of the degrees consider'd absolutely in themselves what is more powerful to divide is also more resistent and harder to be divided And this arrives in that degree which makes water for the falling and beating of the atomes upon water hath the power both to divide and make it descend but so that by making it descend it divideth it And therefore we say it has more gravity then density though it be the very density of it which is the cause that makes it partible by the working of one part upon another for if the atomes did not find the body so dense as it is they could not by their beating upon one part make another be divided So that a dense body to be more heavy then
in bulk but the small ones very hardly Next the smalness and well-working of the parts by means of the airs penetrating every dense one and sticking close to every one of them and consequently joyning them without any unevenness causes that there can be no ruggedness in it and therfore 't is glibb in like manner as we see plaister or starch become smooth when they are well wrought Then the humidity of it causes it to be catching and the shortness of every part makes that where it sticks it is not easily parted thence Now the rarity of air next to fire admits it to be of all the other Elements most easily brought to the height of fire by the operation of fire upon it And therfore oyls are the proper food of that Element And accordingly we see if a drop of oyl be spill'd upon a sheet of paper and the paper set on fire at a corner as the fire comes near the oyl the oyl will disperse and spread it self upon the paper to a broader compass then it had because the heat rarifies it and so in Oyl it self the fire rarifying the air makes it penetrate the earthy parts adjoynd to it more then it did and so subtilizes them till they be reduced to such a height as they are within the power of fire to communicate its own nature to them and thus it turns them into fire and carries them up in its flame But if fire be predominant over earth and air in a watry compound it makes the body so proportion'd to be subtile rare penetrative hot in operation light in weight and subject to burn Of this kind are all sorts of wines and distil'd Spirits commonly called strong waters or Aquavites in Latine Aquaeardentes These will lose their virtues meerly by remaining uncover'd in the air for fire doth not incorporate strongly with water but if it find means raises it self into the air As we see in the smoke of boyling water which is nothing else but little bodies of fire that entring into the water rarifie some parts of it but have no inclination to stay there and therefore as fast as they can get out fly away but the humide parts of the water which they have rarified being of a sticking nature joyn themselves to them and ascend in the air as high as the fiery atomes have strength to carry them which when it fails them that smoke falls down in a dew and so becomes water again as it was All which one may easily discern in a glasse-vessel of water set over the fire in which one may observe the fire come in at the bottome and presently swim up to the top like a little bubble and immediately rise from thence in smoke and that will at last convert it self into drops and settle upon some solid substance thereabouts Of these fiery spirits some are so subtile as of themselves they will vanish and leave no residue of a body behind them and Alchymists profess to make them so etherial and volatile that being pour'd out of a glass from some reasonable height they shall never reach the ground but before they come thither be so rarified by that little motion as they shall grow invisible like the air and dispersing themselves all about in it fill the chamber with the smell of that body which can no longer be seen The last excess in watery bodies must be of water it self which is when so little a proportion of any of the other is mingled with it as is hardly perceptible Out of this composition arise all those several sorts of juices or liquors we commonly call Waters which by their mixture with the other three Elements have peculiar properties beyond simple Elemental water The general quality whereof we shall not need any further to express because by what we have already said of water in common they are sufficiently known In our next survey we will take Earth for our ground to work upon as hitherto we have done water which if in any body it be in the utmost excess beyond all the other three then rocks and stones will grow out of it whose driness and hardness may assure us that Earth sways in their composition with the least allay that may be Nor doth their lightness in respect of some other earthy compositions impeach this resolution for that proceeds from the greatness and multiplicity of pores wherwith their driness causes them to aboundâ— and hinders not but that their real solid parts may be very heavy Now if we mingle a considerable proportion of water with earth so as to exceed the fire and air but still inferiour to the earth we shall poduce metals whose great weight with their ductility and malleability plainly tells us that the smallest of waters gross parts are the glew that holds the earthy dense ones together such weight belonging to earth and that easie changing of parts being most proper to water Quick-silver that is the general matter wherof all the metals are immediately composed gives us evidence hereof for fire works upon it with the same effect as upon water And the calcination of most of the metals proves that fire can easily part and consume the glew by which they were closed and held together which therfore must be rather of a watry then of an aiery substance Likewise the glibness of Mercury and of melted metals without catching or sticking to other substances gives us to understand that this great temper of a moist Element with earth is water and not air and that the watry parts are comprised and as it were shut up within the earthy ones for air catches and sticks notably to all things it touches and will not be imprisoned the divisibility of it being excceeding great though in never so short parts Now if air mingles it self with earth and be prodominant over water and fire it makes such an oily and fat soil as Husbandmen account their best mould which receiving a betterment from the Sun temperate heat assures us of the concourse of the aire for wherever such heat is air cannot fail of accompanying or being effected by it and the richest of such earth as pot-earth and marl will with much fire grow more compacted and stick closer together then it did as we see in baking them into pots or fine bricks Whereas if water were the glew between the dense parts fire would consume it and crumble them asunder as it doth in those bodies it calcines And excesse of fire will bring them to vitrification which still confirms that air abounds in them for it is the nature of air to stick so close where once it is kneaded in as it cannot be separated without extreme difficulty And to this purpose the viscuous holding together of the parts of glass when it is melted shews evidently that air abounds in vitrified bodies The last mixture we are to meddle with is of fire with earth in an over-ruling
continual application to the body it thus anatomises hath harden'd as it were rosted some parts into such greatness and driness as they will not flie nor can be carried up with any moderate heat But great quantity of fire being mingled with the subtiler parts of his baked earth makes them very pungent and acrimonious in tast so that they are of the nature of ordinary Salt and so called and by the help of water may easily be separated from the more gross parts which then remain a dead and useless earth By this discourse 't is apparent that fire has been the instrument which hath wrought all these parts of an entire body into the forms they are in for whiles it carried away the fiery parts it swel'd the watry ones and whiles it lifted up them it digested the Aerial parts and whiles it drove up the Oyle it baked the earth and salt Again all these retaining for the most part the proper nature of the substance from whence they are extracted 't is evident that the substance is not dissolv'd for so the nature of the whole would be dissolv'd and quite destroy'd extinguish'd in every part but that onely some parts containing the whole substance or rather the nature of the whole substance in them are separated fromo ther parts that have likewise the same nature in them The third instrument for the separation and dissolution of bodies is Water whose proper matter to work upon is Salt and it serves to supply what the fire could not perform which is the separation of the salt from the earth in calcined bodies All the other parts fire was able to sever but in these he hath so baked the little humidity he hath left in them with their much earth as he cannot divide them any further and so though he incorporates himself with them yet he can carry nothing away with him If then pure water be put upon that chalk the subtilest dry parts of it easily joyn to the supervenient moysture and sticking close to it draw it down to them But because they are the lighter it happens to them as when a man in a boat pulls the land to him that comes not to him but he removes himself and his boat to it so these ascend in the water as they dissolve And the water more and more penetrating them and by addition of its parts making the humidity which glews their earthy parts together greater and greater makes a wider and wider separation between those little earthy parts and so imbues the whole body of the water with them into which they are dispersed in little atomes Those that are of biggest bulk remain lowest in the water and in the same measure as their quantities dissolve into less and less they ascend higher and higher till at length the water is fully replenish'd with them and they are diffused through the whole body of it whiles the more gross and heavy earthy parts having nothing in them to make a present combination between them and the water fall down to the bottome and settle under the water in dust In which because earth alone predominates in a very great excess we can expect no other virtue to be in it but that which is proper to mere earth to wit driness and weight Which ordinary Alchimists look not after and therfore call it Terra damnata but others find a fixing quality in it by which they perform very admirable operations Now if you prove the impregnated water from the Terra damnata and then evaporate it you will find a pure white substance remaining Which by its bulk shews it self to be very earthy and by its pricking and corrasive taste will inform you much fire is in it and by its easie dissolution in a moist place that water had a great share in the production of it And thus the salts of bodies are made and extracted Now as water dissolves salt so by the incorporation and virtue of that corrosive substance it doth more then salt it self can do for having gotten acrimony and more weight by the mixture and dissolution of salt in it it makes it self away into solide bodies even into metalls as we see in brass and iron which are easily rusted by salt dissolving upon them And according as the salts are stronger so this corrasive virtue encreases in them even so much as neither silver nor gold are free from their eating quality But they as well as the rest are divided into most small parts and made to swim in water in such sort as we have explicated above and wherof every ordinary Alchymist teaches the practise But this is not all salts help as well to melt hard bodies and metalls as to corrode them For fome fusible salts flowing upon them by the heat of the fire and others dissolv'd by the steam of the metal that incorporates with them as soon as they are in flux mingle with the natural juice of the metals and penetrate deeper then without them the fire could do and swell them and make them fit to run These are the principal ways of the two last instruments in dissolving of bodies taking each of them by it self But there remains one more of very great importance as well in the works of nature as of art in which both the former are joyned and concur and that is putrefaction Whose way of working is by gentle heat and moisture to wet and pierce the body it works upon wherby 't is made to swel and the hot parts of it being loosen'd they are at length drunk up and drown'd in the moist ones from whence by fire they are easily separated as we have already declared and those moist parts afterwards leaving it the substance remaines dry and falls in pieces for want of the glew that held it together CHAP. XVI An explication of certain Maxims touching the operations and qualities of bodies and whether the Elements be found pure in any part of the World OUt of what we have determin'd concerning the natural actions of bodies in their making and destroying one another 't is easie to understand the right meaning of some terms and the true reason of some maxims much used in the Schools As first when Philosophers attribute to all sorts of corporeal Agents a Sphere of Activity The sense of that manner of expression in fire appears plainly by what we have already declared of the nature and manner of operation of that Element And in like manner if we consider how the force of cold consists in a compression of the body that is made cold we may perceive that if in the cooled body there be any subtile parts which can break forth from the rest such compression wil make them do so Especially if the compression be of little parts of the compressed body within themselvs as well as of the outward bulk of the whole body round about For at first the compression of such causes in the body
uppermost stone and exactly in the middle of it Then by that ring pull it up perpendicularly and steadily and the undermost will follow sticking fast to the overmost and though they were not very perfectly polished yet the nethermost would follow for a while if the ring be suddenly plucked up but then it will soon fall down again Now this plainly shews that the cause of their sticking so strongly together when both the stones are very well polished is for that nothing can well enter between them to part them and so 't is reduced to the shortness of the air betwixt them which not being capable of so great an expansion nor admitting to be divided thick-ways so much as is necessary to fill the first growing distance between the two stones till new air finds a course thither that so the swelling of the one may hinder vacuity till the other come into the rescue the two stones must needs stick together to certain limits which limits will depend of the proportion that is between the weight and the continuity of the nethermost stone And when we have examin'd this we shall understand in what sense it is meant that Nature abhors from Vacuity and what means she uses to avoid it For to put it as an enemy that nature fights against or to discourse of effects that would follow from it in case it were admitted is a great mistake and a lost labour seeing it is nothing and therfore can do nothing but is meerly a form of expression to declare in short nothing else but that it is a contradiction or implication in terms and an impossibility in nature for Vacuity to have or be supposed to have a Being Thus then since in our case after we have cast all about we can pitch upon nothing to be consider'd but that the two stones touch one another and that they are weighty we must apply our selvs only to reflect upon the affects proceeding from these two causes their contiguity and their heaviness and we shall find that as the one of them namely the weight hinders the undermost from following the uppermost so contiguity obliges it to that course and according as the one overcoms the other so will this action be continued or interrupted Now that contiguity of substances makes one follow another is evident by what our Masters in Metaphysicks teach us when they shew that without this affect no motion at all could be made in the world nor any reason given for those motions we daily see For since the nature of quantity is such that whenever there is nothing between two parts of it they must needs touch and adhere and joyn to one another for how should they be kept asunder when there is nothing between them to to part them if you pull one part away either some new substance must come to be close to that which removes or else the other which was formerly close to it must still be close to it and so follow it for if nothing come between it is still close to it Thus then it being necessary that somthing must be joyn'd close to every thing Vacuity which is nothing is excluded from having any being in nature And when we say that one body must follow another to avoid vacuity the meaning is that under the necessity of a contradiction they must follow one another and that they cannot do otherwise For it would be a contradiction to say that nothing were between two things and yet that they are not joyn'd close to one another and therfore if you should say it you would in other words say they are close together and they are not close together In like manner to say that Vacuity is any where is a pure contradiction for Vacuity being nothing has no Being at all and yet by those words it is said to be in such a place so that they affirm it to be and not to be at the same time But now let us examine if there be no means to avoid this contradiction and vacuity other then by the adhesion following of one body upon the motion of another that is closely joyn'd to it and every where contiguous For sense is not easily quieted with such Metaphysical contemplations that seem to repugn against her dictamens and therefore for her satisfaction we can do no less then give her leave to range about and cast all waies in hope of finding some one that may better content her which when she finds that she cannot she will the less repine to yield her assent to the rigorous sequels and proofs of reason In this difficulty then after turning on every side I for my part can discern no pretence of probability in any other means but pulling down the lower stone by one corner that so there may be a gaping between the two stones to let in air by little and little And in this case you may say that by the intervention of air Vacuity is hinder'd and yet the lower stone is left at liberty to follow its own natural inclination and be govern'd by its weight But indeed if you consider the matter well you will find that the doing this requires a much greater force then to have the lower stone follow the upper for it cannot gape in a straight line to let in air since in that position it must open at the bottom where the angle is made at the same time that it opens at the mouth and then air requiring time to pass from the edges to the bottom it must in the mean while fal into the contradiction of Vacuity So that if it should open to let in air the stone to compass that effect must bend in such sort as wood doth when a wedg is put into it to cleave it Judge then what force it must be that should make hard marble of a great thickness bend like a wand and whether it would not rather break and slide off then do so you will allow that a much less will raise up the lower stone together with the uppermost It must then of necessity fall out that it will follow it if it be moved perpendicularly upwards And the like effect will be though it should be raised at oblique angles so that the lower-most edge do rest all the way upon somthing that may hinder the inferiour stone from sliding aside from the uppermost And this is the very case of all those other experiments of art and nature which we have mention'd above for the reason holds as well in water and liquide things as in solid bodies till the weight of the liquid body overcome's the continuity of it for then the thrid breaks and it will ascend no higher Which height Galileo tells us from the workmen in the Arsenal of Venice is 40 foot if the water be drawn up in a close pipe in which the advantage of the sides helps the ascent But others say that the invention is inlarged and that water
it upon a hedge as that dries away so will their sore amend In other parts they observe that if milk newly come from the cow in the boyling run over into the fire and that this happen often and near together to the same cows milk that cow will have her udder sore inflamed and the prevention is to cast salt immediately into the fire upon the milk The herb Persicaria if it be well rub'd upon Warts and then be laid in some fit place to putrifie causes the Warts to wear away as it rots some say the like of fresh Beef Many examples also there are of hurting living creatures by the like means which I set not down for fear of doing more harm by the evil inclination of some persons into whose hands they may fall then profit by their knowing them to whom I intend this work But to make these operations of nature not incredible let us remember how we have determin'd that every body whatever yields some steam or vents a kind of vapour from it self and consider how they must needs do so most of all that are hot and moist as bloud and milk and all wounds and sores generally are We see that the foot of a Hare or Bear leaves such an impression where the beast has passed as a dog can discern it a long time after and a Fox breaths out so strong a vapour that the hunters themselvs can wind it a great way off and a good while after he is parted from the place Now joyning this to the experiences we have already allow'd of concerning the attraction of heat we may conclude that if any of these vapours light upon a solid warm body which has the nature of a source to them they will naturally congregate and incorporate there and if those vapours be joyn'd with any medicative quality or body they will apply that medicament better then any Chirurgeon can Then if the steam of bloud bloud and spirits carry with it from the weapon or cloth the balsamike qualities of the salve or powder and with them settle upon the wound what can follow but a bettering in it Likewise if the steam of the corruption that is upon the clod carry the drying quality of the wind which sweeps over it when it hangs high in the air to the sore part of the cows foot why is it not possible that it should dry the corruption there as well as it dryes it upon the hedge And if the steam of burned milk can hurt by carrying fire to the dug why should not salt cast upon it be a preservative against it Or rather why should not salt hinder the fire from being carried thither Since the nature of salt always hinders and suppresses the activity of fire as we see by experience when we throw salt into the fire below to hinder the flaming of soot in the top of a chimney which presently ceases when new fire from beneath doth not continue it And thus we might proceed in sundry other effects to declare the reason and possibility were we certain of the truth of them therfore we remit this whole question to the authority of the testimonies CHAP. XIX Of three other motions belonging to particular bodies Filtration Restitution and Electrical attraction AFter these let us cast our eye upon another motion very familiar among Alchymists which they call Filtration It is effected by putting one end of a tongue or label of Flannen or Cotten or Flax into a vessel of water and letting the other end hang over the brim of it And it will by little and little draw all the water out of that vessel so that the end which hangs qâ—t be lower then the superficies of the water and make it all come over into any lower vessel you will reserve it in The end of this operation is when any water is mingled with gross and muddy parts not dissolv'd in the water to separate the pure light ones from the impure By which we are taught that the lighter parts of the water are those which most easily catch And if we will examine in particular how 't is likely this business passes we may conceive that the body or linguet by which the water ascends being a dry one some lighter parts of the water whose chance it is to be near the climbing body of Flax begin to stick fast to it and then they require nothing near so great force nor so much pressing to make them climb up along the flax as they would do to make them mount in the pure air As you may see if you hold a stick in running water shelving against the stream the water will run up along the stick much higher then it could be forced up in the open air without any support though the agent were much stronger then the current of the stream And a ball will on a rebound run much higher upon a shelving board then it would if nothing touch'd it And I have been told that if an egsshell fill'd with dew be set at the foot of a hollow stick the Sun will draw it to the top of the shelving stick wheras without a prop it will not stir it With much more reason then we may conceive that water finding as it were little steps in the Cotton to facilitate its journy upwards must ascend more easily then those other things do so as it once receive any impulse to drive it upwards For the gravity both of that water which is upon the Cotton as also of so many of the confining parts of water as can reach the Cotton is exceedingly allay'd either by sticking to the Cotton and so weighing in one bulk with that dry body or else by not tending down straight to the Center but resting as it were upon a steep plain according to what we said of the arm of a Syphon that hangs very sloping out of the water and therfore draws not after it a less proportion of water in the other arm that is more in a direct line to the Center by which means the water as soon as it begins to climb comes to stand in a kind of cone neither breaking from the water below its bulk being big enough to reach to it nor yet falling down to it But our chief labour must be to finde a cause that may make the water begin to ascend To which purpose consider how water of its own nature compresses it self together to exclude any other body lighter then it is Now in respect of the whole mass of the water those parts which stick to the cotton are to be acounted muchlighter then water not because in their own nature they are so but for the circumstances which accompany and give them a greater disposition to receive a motion upwards then much lighter bodies whiles they are destitute of such helps Wherfore as the bulk of water weighing and striving downwards it follows that if there were any air mingled with it it would to
possess a lesser place drive out the aire so here in this case the water at the foot of the ladder of cotton ready to climb with a very small impulse may be after some sort compared in respect of the water to air by reason of the lightness of it and consequently is forced up by the compressing of the rest of water round about it Which no faster gets up but other parts at the foot of the ladder follow the first and drive them still upwards along the tow and new ones drive the second and others the third and so forth so that with ease they climb up to the top of the filter still driving one another forwards as you may do a fine towel through a musket barrel which though it be too limber to be thrust straight through yet craming still new parts into it at length you will drive the first quite through And thus when these parts of water are got up to the top of the vessel on which the filter hangs and over it on the other side by sticking still to the tow and by their natural gravity against which nothing presses on this side the label they fall down again by little and little and by drops break again into water in the vessel set to receive them But now if you ask why it will not drop unless the end of the label that hangs be lower then the water I conceive it is because the water which is all along upon the flannen is one continued body hanging together as it were a thrid of wire and is subject to like accidents as such a continued body is Now suppose you lay wire upon the edge of the basin which the filter rests on and so make that edge the Centre to ballance it upon if the end that is outermost be heaviest it will weigh down the other otherwise not So fares it with this thrid of water if the end of it that hangs out of the pot be longer and consequently heavier then that which rises it must needs raise the other upwards and fall it self downwards Now the raising of the other implies lifting more water from the Cistern and the sliding of it self further downwards is the cause of its converting into drops So that the water in the cistern serves like the flax upon a distaff and is spun into a thrid of water still as it comes to the flannen by the drawing it up occasion'd by the overweight of the thrid on the other side of the center Which to express better by a similitude in a solid body I remember I have oftentimes seen in a Mercers shop a great heap of massy gold lace lie upon their stall and a little way above it a round smooth pin of wood over which they use to have their lace when they wind it into bottoms Now over this pin I have put one end of the lace as long as it hung no lower then the board upon which the rest of the lace did lie it stird'd not for as the weight of the loose end carried it one way so the weight of the otherside where the whole was drew it the otherway in this manner kept it in equalibrity But as soon as I drew on the hanging end to the heavier then the climbing side for no more weights then is in the air that which lies upon the board having another center then it began to roule to the ground and still drew up new parts of that which lay upon the board till all was tumbled down upon the floor In the same manner it hap'nes to the water in which the thrid of it upon the filter is to be compared fitly to that part of the lace which hung upon the pin and the whole quantity in the cistern is like the bulk of lace upon the Shopboard for as fast as the filter draws it up 't is converted into a thrid like that which is already upon the filter in like manner as the wheel converts the flax into yarn as fast as it draws it out from the distaff Our next consideration will very aptly fall upon the motion of those things which being bent leap with violence to their former figure wheras others return but a little and others stand in that ply wherin the bending hath set them For finding the reason of which effects our first reflection may be to note that a Superficies which is more long then broad contains a less floor then that whose sides are equal or nearer being equal and that of those surfaces whose lines and angles are all equal that which hath most sides and angles contains still the greater floor Whence it is that Mathematicians conclude a circle to be the most capacious of all figures and what they say of lines in respect of a superficies the same with proportion they say of surfaces in respect of the body contained And accordingly we see by consequence that in the making a bag of a long napkin if the napkin be sew'd together longwise it holds a great deal less then if it be sewd together broadwise By this we see plainly that if any body in a thick and short figure be forced into a thinner which by becoming thinner must likewise become either longer or broader for what it loses one way it must get another then that superficies must needs be stretched which in our case is a Physical outside or material part of a solid body not a Mathematical consideration of an indivisible Entity We see also that this change of figures happens in the bending of all those bodies wherof we are now enquiring the reason why some of them restore themselves to their original figures and others stand as they are bent Then to begin with the latter sort we find that they are of a moist nature as among metalls lead and tin and among other bodies those â—which we account soft And we may determine that this effect proceeds partly from the humidity of the body that stands bent and partly from a driness peculiar to it that comprehends and fixes the humidity of it For by the first they are render'd capable of being driven into any figure which nature or art desires and by the second they are preserv'd from having their gravity put them out of what figure they have once receiv'd But because these two conditions are common to all solid bodies we may conclude that if no other circumstance concur'd the effect arising out of them would likewise be common to all such and therfore where we find it otherwise we must seek further for a cause of that transgression As for example if you bend the bodies of young trees or the branches of others they will return to their due figure 'T is true they will somtimes lean towards that way they have been bent as may be seen even in great trees after violent tempests and generally the heads of trees the ears of corn and the grown hedg rows will all bend one way
the first the doubting of Beasts and their long wavering somtimes between objects that draw them several ways and at last their resolving upon some one of them and their steady pursuance of that afterwards these will not be matter of hard digestion to him that shall have well relished meditated on the contents of the last Chapter For 't is evident that if several objects of different natures at the same time present themselvs to a living creature they must of necessity make divers impressions in the heart of it proportionable to the causes from whence they proceed so that if one of them be a motion of hope and the other of fear it cannot choose but follow thence that what one of them begins the other will presently break off By which means it will come to pass that in the Beasts heart there must needs be such waverings as we may observe in the Sea when at the beginning of a tide of flood it meets with a bank that checks the coming in of the waves and for a while bears them back as fast as they press upon it they offer at getting over it and by and by retire back again from the steepness of it as though they were apprehensive of some danger on the other side and then again attempt it afresh and thus continue labouring one while one way another while another till at length the floud increasing the water seems to grow bolder and breaks amain over the banks and then flows on till it meets with another that resists it as the first did And thus you see how the Sea can doubt and resolve without any discoursing In like manner it fares with the heart of a Beast whose motions steer the rest of the body when it beats betwen hope and fear or between any other two contrary passions without requiring any other principles from whence to deduce it than those we have already explicated But now to speak of their invention I must confess that among several of them there appears so much cunning in laying of their plots which when they have compassed they seem to grow careless and unbend their intention as having obtain'd what with earnestness they desired that one might think they wrought by design and had a distinct view of an end for the effecting of which they used discourse to choose the likeliest means To this purpose the subtilties of the Fox are of most note They say he uses to lie as if he were dead therby to make Hens and Ducks come boldly to him That in the night when his body is unseen he will fix his eyes upon poultry and so make them come down to him from their roost That to rid himself of the fleas that afflict him in the Summer he will sink his body by little and little into the water while the fleas creep up to his head to save themselves from drowning and from thence to a bough he holds in his mouth and will then swim away leaving them there That to cousen the Badger of his earth he will piss in it as knowing that the rank smell of his Urine will drive the other cleanlier beast to quit it That when Dogs are close upon him and catching at him he will piss upon his Tail and by firking that up and down will endeavour you may believe to make their eyes smart and so retard their pursuit that he may escape from them And there are particular stories that express yet more cunning than all these As of a Fox that being sore hunted hang'd himself by the teeth among dead vermin in a Warren till the Doggs were pass'd by him and had lost him Of another that in like distress would take into his mouth a broom bush growing upon a sleep cliff on the side hand neer his Den which had another way to it easie enough of access and by help of that would securely cast himself into his hole while the Dogs that follow'd him hastily and were ignorant of the danger would break their necks down the rocks 'T is said that in Thracia the Countrey people know whether the rivers that are frozen in the winter will bear them or no by marking whether the Foxes venture boldly over them or retire after they have lai'd their ears to the Ice to listen whether they can hear the noise of the water running under it from whence you may imagine they collect that if they hear the current of the stream the Ice must needs be thin and consequently dangerous to trust their weight to it And to busie my self no longer with their subtilties I will conclude with a famous tale of one of these crafty animals that having kill'd a Goose on the other side of the river and being desirous to swim over with it to carry it to his den before he would attempt it lest his prey might prove too heavy for him to swim withal and so he might lose it he first weigh'd the Goose with a piece of wood and then tri'd to carry that over the river whiles he left his Goose behind in a safe place which when he perciev'd he was able to do with ease he then came back again and ventured over with his heavy bird They say it is the nature of the Iacatray to hide it self and imitate the voice of such beasts as it uses to prey upon which makes them come to him as to one of their own fellows and then he seises on and devours them The Iaccal that has a subtile sent hunts after beasts and in the chase by his barking guides the Lion whose nose is not so good till they overtake what they hunt which peradventure would be too strong for the Iaccall but the Lion kills the quarry and having first fed himself leaves the Iaccal his share and so between them both by the ones dexterity and the others strength they get meat for nourishment of them both Like stories are recorded of some Fishes And every day we see the invention of Beasts to save themselvs from catching as Hares when they are hunted seeks always to confound the sent somtimes by taking hedges otherwhiles waters somtimes running among sheep and other beasts of stronger sent somtimes making doubles and treading the same path over and over and somtimes leaping with great jumps hither and thither before they betake themselves to their rest that so the continuateness of the sent may not lead doggs to their form Now to penetrate into the causes of these and of such like actions we may remember how we shew'd in the last Chapter that the beating of the heart works two things one is that it turns about the specieses or little corporeities streaming from outward objects which remain in the memory the other is that it is always pressing on to some motion or other Out of which it happens that when the ordinary ways of getting victuals or escaping from enemies fail a creature whose constitution is active it lights somtimes though
will the same happen in so difficult and spiny an affair as the writing on such a nice and copious Subject as this is to one who is so wholly ignorant of the Laws of Method as I am This free and ingenuous acknowledgment on my side will I hope prevail with all ingenuous person who shall read what I have written to advertise me fairly if they judg it worth their while of what they dislike in it to the end that in another more accurate Edition I may give them better satisfaction For besides what failings may be in the Matter I cannot doubt but even in the Expressions of it there must often be great obscurity and shortness which I who have my thoughts filled with the things themselvs am not aware of So that what peradventure may seem very full to me because every imperfect touch brings into my mind the entire notion and whole chain of circumstances belonging to that thing I have so often beaten upon may appear very crude and maimed to a Stranger that cannot guess what I should be at otherwise than as my direct words lead him One thing more I shall wish you to desire of them who happily may peruse these two Treatises as well for their own sakes as for mine And that is that they will not pass their censure upon any particular piece or broken parcel of either of them taken by itself Let them draw the entire Thrid through their fingers and examine the consequentness of the Whole Body of the doctrine I deliver and let them compare it by a like survey with what is ordinarily taught in the Schools and if they find in theirs many bracks and short ends which cannot be spun into an even piece and in mine a fair coherence througout I shall promise my self a favourable doom from them and that they will have an acquiescence in themselvs to what I have here presented them Whereas if they but ravel it over looslie and pitch upon dispuiting against particular Conclusions that at the first encounter of them single may seem harsh to them which is the ordinary course of Flashy Wits who cannot fadome the whole extent of a large discourse 't is impossible but that they should be very much unsatisfied of me and go away with a perswasion that some such Truths as upon the whole matter are most evident one stone in the Arch supporting another and the whole are meer Chymeras and wild Paradoxes But Son 't is time my Book should speak it self rather than I speak any longer of it here Read it carefully over and let me see by the effects of your Governing your self that you make such right use of it as I may be comforted in having chosen you to bequeath it to God in Heaven bless you Paris the last of August 1644. Your loving Father KENELM DIGBY TABLE Of the First TREATISE CONCERNING BODIES PREFACE CHAP. I. A Preamble to the whole Discourse Concerning Notions in general 1. Quantity is the first and most obvious affection of a body 2. Words do not express things as they are in themselvs but only as they are painted in the minds of men 3. The first error that may arise from hence which is a multiplying of things where no such multiplication is really found 4. A second errour the conceiving many distinct things as really one thing 5. Great care to be taken to avoid the errours which may arise from our mannner of understanding things 6. Two sorts of words to express our notions the one common to all men the other proper to scholars 7. Great errours arise by wresting words from their common meaning to express a more particular or studied notion CHAP. II. Of Quantity 1. We must know the vulgar and common notion of Quantity that we may understand the nature of it 2. Extension or divisibility is the common notion of Quantity 3. Parts of Quantity aâ—e not actually in their whole 4. If parts were actually in their whole Quantity would be composed of indivisibles 5. Qantity cannot be composed of indivisibles 6. An objection to prove that parts are actually in Quantity with a declaration of the mistake from whence it proceeds 7. The solution of the former objection and that sense cannot discern whether one part be distinguished from another or no. 8. An enumeration of the several specieses of Quantity which confirmes that the essence of it is divisibility CHAP. III. Of Rarity and Density 1. What is meant by Rarity and Density 2. It is evedent that some bodies are rare and others Dense though obscure how they are such 3. A brief enumeration of the several properties belonging to rare and dense bodies 4. The Opinion of those Philosophers declared who put rarity to consist in an actual division of a body into little parts 5. The former opinion rejected and the ground of their errour discovered 6. The opinion of those Philosophers related who put rarity to consist in the mixtion of vacuity among bodies 7. The opinion of vacuities refuted 8. Rarity and Density consist in the severall proportions which Quantity hath to its Substance 9. All must admit in Physical bodies a Metaphysical composition CHAP. IV. Of the four First Qualities and of the four Elements 1. The notions of Density and rarity have a latitude capable of infinite variety 2. How moistness and driness are begotten in dense bodies 3. How moistness and dryness are begotten in rare bodie 4. Heat is a property of rare bodies and cold of dense ones 5. Of the two dense bodies the less dense is more cold but of the two rare ones the less rare is less hot 6. The extreme dense body is more dry than the extreme rare one 7. There are but four simple bodies and these are rightly named Elements 8. The Authour doth not determine whether every Element doth comprehend under its name one onely lowest species or many nor whether any of them be found pure CHAP. V. Of the operations of the Elements in general And of their Activities compared with one another 1. The first operation of the Elements is division out of which results local motion 2. What place is both notionally and really 3. Local motion is that division wherby a body changes its place 4. The nature of quantity of it self is sufficient to unite a body to its place 5. All operations amongst bodies are either local motions or such as follow out of local motion 6. Earth compared to Water in activity 7. The manner wherby fire gets into fewel proves that it exceeds earth in activity 8. The same is proved by the manner wherby fire comes out of fewel and works upon other bodies CHAP. VI. Of Light what it is 1. In what sense the Authour rejects qualities 2. In what sense the Authour admits of qualities 3. Five arguments proposed to prove that light is not a body 4. The two first reasons to prove Light a body are the resemblance it hath with fire and because if it were a
refraction 6. An answer to the arguments brought in favour of Monsieur des Cartes his opinion 7. The true cause of refraction of light both at its entrance and at its going out from the refleing body 8. A general rule to know the nature of reflection and refractions in all sorts of surface 9. A body of greater parts and greater pores makes a greater refraction than one of lesser parts and lesser pores 10. A confirmation of the former doctrine out of the nature of bodies that refract light CHAP. XIV Of the composition qualities Generation of mixed Bodies 1. The connexion of this chapter with the rest and the Authours intent in it 2. That there is a least sise of bodies and that this least sise is found in fire 3. The first conjunction of parts is in bodies of least sise and it is made by the force of Quantity 4. The second sort of conjunction is compactedness in simple Elements and it proceeds from density 5. The third conjunction is of parts of different Elements and it proceeds from quantity and density together 6. The reason why liquid bodies do easily joyn together and dry ones difficultly 7. That no two hard bodies can touch one another immediately 8. How mixed bodies are framed in general 9. The cause of the several degrees of solidity in mixed bodies 10. The Rule whereto are reduced all the several combinations of Elements in compounding of mixed bodies 11. Earth and water are the basis of all permanent mixed bodies 12. What kind of bodies those are where water is the basis and earth the predominant Element over the other two 13. Of those bodies where water being the basis air is the predominant Element 14. What kind of bodies result where water is the basis and fire the predominant Element 15. Of those bodies where water is in excess it alone being both the basis and the predominant Element 16. Of those bodies where earth alone is the basis and also the predominant in excess over the other three Elements 17. Of those bodies where earth is the basis water is the predominant element over the other two 18. Of those bodies where earth being the basis air is the predominant 19. Of those bodies where earth being the basis fire is the predominant 20. All the second qualities of mixed bodies arise from several combinations of the first qualities and are at last resolv'd into several degrees of rarity density 21. That in the Planets Stars there is a like variety of mixed bodies caused by light as here on earth 22. In what manner the Elements work on one another in the composition of mixed bodies and in particular fire which is the most active 23. A particular declaration touching the generation of Metals CHAP. XV. Of the Dissolution of Mixed Bodies 1. Why some bodies are brittle and others tough or apt to withstand outward violence the first instrument to dissolve mixed bodies 2. How outward violence doth work on the most compacted bodies 3. The several effects of fire the second and chiefest instrument to dissolve all compounded bodies 4. The reason why some bodies are not dissolved by fire 5. The reason why fire melteth gold but cannot consume it 6. Why Lead is easily consumed and calcinted by fire 7. Why and how some bodies are divided by fire into Spirits Waters Oyls Salts and Earth And what those parts are 8. How water the third instrument to dissolve bodies dissolvs calx into salt and so into terra damnata 9. How water mingled with salt becomes a most powerful Agent to dissolve other bodies 10. How putrefaction is caused CHAP. XVI An Explication of certain Maxims touching the operations and qualies of bodies and whether the Elements be found pure in any part of the world 1. What is the Sphere of activity in corporeal agents 2. The reason why no body can work in distance 3. An objection answer'd against the manner of explicating the former axiome 4. Of re-action and first in pure local motion that each Agent must suffer in acting and act in suffering 5. The former Doctrine applyed to other local motions design'd by particular names And that Suisseths argument is of no force against this way of doctrine 6. Why some notions do admit of intension and remission and others not 7. That in every part of our habitable world all the four elements are found pure in small atoms but not in any great bulk CHAP. XVII Of Rarefaction and Condensation the two first motions of Particular bodies 1. The Authours intent in this and the following chapters 2. That bodies may be rarified both by outward and inward heart and how this is perform'd 3. Of the great effects of Rarefaction 4. The first manner of condensation by heat 5. The second manner of condensation by cold 6. That Ice is not water rarified but condensed 7. How Wind Snow and Hail are made and wind by rain allaid 8. How parts of the same or divers bodies are joyn'd more strongly together by condensation 9. Vacuities cannot be the reason why water impregnated to the full with one kind of salt will notwithstanding receive more of another 10. The true reason of the former effect 11. The reason why bodies of the same nature do joyn more easily together than others CHAP. XVIII Of another motion belonging to Particular bodies called Attraction and of certain operations term'd Magical 1. What Attraction is and from whence it proceeds 2. The true sense of the Maxime that Nature abhors from vacuitys 3. The true reason of attraction 4. Water may be brought by the force of attraction to what height soever 5. The doctrine touching the attraction of water in Syphons 6. That the Syphon doth not prove water to weigh in its own orb 7. Concerning attraction caus'd by fire 8. Concerning attraction made by virture of hot bodies amulets c 9. The natural reason given for divers operations esteem'd by some to be magical CHAP. XIX Of three other motions belonging to particular bodies Filtration Restitution and Electrical attraction 1. What is Filtration and how it is effected 2. What causes the water in Filtration to ascend 3. Why the filter will not drop unless the label hang lower than the water 4. Of the motion of Restitution and why some bodies stand bent others not 5. Why some bodies return only in part to their natural figure others entirely 6. Concerning the nature of those bodies which shrink aand stretch 7. How great and wonderful effects proceed from small plain and simple principles 8. Concerning Electrical attratâ—on and the causes of it 9. Cabeus his opinion refuted concerning the cause of Electrical motions CHAP. XX. Of the Loadstones generation and its particulas motions 1. The extreme heat of the Sun under the Zodiack draws a stream of air from each Pole into the torrid Zone 2. The atomes of these two streams coming together are apt to incorporate with one another 3. By the meeting and mingling together
will pierce cut out the water almost into as little parts as themselves and mingling themselves with them they will flie away together and so convert the whole body of water into subtile smoke whereas the same Agent after long working upon lead will bring it into no less parts then small grains of dust which it calcines it into And gold that is more dense then lead resists peremptorily all the dividing power of fire and will not at all be reduced into a calx or lime by such operation as reduced lead into it So that remembring how the nature of Quantity is Divisibility and considering that rare things are more divisible then dense ones we must needs acknowledge that the nature of Quantity is some way more perfectly in things that are Rare then in those that are Dense On the other side more compacted and dense things may haply seem to some to have more Quantity then those that are rare and that is but shrunk together which may be stretch'd out and driven into much greater dimensions then the Quantity of rare things taking the quantities of each equal in outward appearance As gold may be beaten into much more and thiner leaf then an equal bulk of silver or lead A wax candle will burn longer with a small light then a tallow candle of the same bigness and consequently be converted into a greater quantity of fire and air Oyl will make much more flame then spirit of wine that is far rarer then it These and such like considerations have much perplex'd Philosophers and driven them into diverse thoughts to find out the reasons of them Some observing that the dividing of a body into little parts makes it less apt to descend then when it is in greater have believ'd the whole cause of lightness and rarity to be derived from division As for example they find that lead cut into little pieces will not go down so fast in water as when it is in bulk and it may be reduced into so smal atomes that it will for some space swim upon the water like dust of wood Which assumption is prov'd by the great Galileus to whose excellent wit and admirable industry the world is beholding not only for his wonderful discoveries made in the Heavens but also for his acurate and learned declaring of those very things that lye under our feet He about the 90. page of his first Dialogue of Motion clearly demonstrates how any real medium must of necessity resist more the descent of a little piece of lead or any other weighty matter than it would a greater piece and the resistance will be greater and greater as the pieces are lesser and lesser So that as the pieces are made less they will in the same medium sink the flower and seem to have acquired a new nature of lightness by the diminution not only of having less weight in them than they had as half an ounce is less than a whole ounce but also of having in themselvs a less proportion of weight to their bulk than they had as a pound of Cork is in regard of its magnitude lighter than a pound of Lead So as they conclude that the thing whose continued parts are the lesser is in its own nature the lighter and the rarer and other things whose continued parts are greater be heavier and denser But this discourse reaches not home for by it the weight of any body being discovered by the proportion it has to the medium in which it descends it must ever suppose a body lighter than it self in which it may sink and go to the bottome Now of that lighter body I enquire what makes it be so and you must answer by what you have concluded that it is lighter then the other because the parts of it are lesse and moreseverd from one another for if they be as close together their division avails them nothing since things sticking fast together work as if they were but one and so a pound of lead though it be filed into small dust if it be compacted hard together will sink as fast as if it were one bulk Now then allowingthe little parts to be seperated I ask what other body fills up the spaces between those little parts of the medium in which your heavy body descends For if the parts of water are more sever'd then the parts of lead there must be some other substance to keep the parts of it asunder let us suppose this to be air and I ask Whether an equal part of air be as heavy as so much water or whether it be not If you say it is then the compound of water and air must be as heavy as lead since their parts one with another are as much compacted as the parts of lead are For there is no difference whether those bodies whose little parts are compacted together be of the same substance or of divers or whether the one be divided into smaller parts then the other or not so they be of equal weights in regard of making the whole equally heavy as you may experience if you mingle pin-dust with a sand of equal weight though it be beaten into far smaller divisions then the pin-dust and put them in a bag together But if you say that air is not so heavy as water it must be because every part of air hath again its parts more sever'd by some other body then the parts of water are sever'd by air And then I make the same instance of that body which severs the parts of air And so at last since there cannot actually be an infinite process of bodies one lighter then another you must come to one whose little parts filling the pores and spaces between the parts of the others have no spaces in themselves to be fil'd up But as soon as you acknowledge such a body to be lighter and rarer then all the rest you contradict and destroy all you said before For by reason of its having no pores it follows by your rule that the little parts of it must be as heavy if not heavier then the little parts of the same bigness of that body whose pores it fills and consequently it is proved by the experience we alledg'd of pin-dust mingled with sand that the little parts of it cannot by their mingling with the parts of the body in which it is immediately contain'd make that lighter then it would be if these little parts were not mingled with it Nor would both their parts mingled with the body which immediately contains them make that body lighter And so proceeding on in the same sort through all the mingled bodies till you come to the last that is immediately mingled with water you will make water nothing the lighter for being mingled with all these and by consequence it should be as heavy and as dense as lead Now that which deceiv'd the Authors of this opinion was that they had not a right intelligence of the causes
neither great nor little and consequently the whole machine raised upon that supposition must be ruinous His argument is to this purpose What is nothing cannot have parts but vacuum is nothing because as the Adversaries conceive it vacuum is the want of a corporeal substance in an inclosing body within whose sides nothing is whereas a certain body might be contain'd within them as if in a pail or bowl of a gallon there were neither milk nor water nor air nor any other body whatever therefore vacuum cannot have parts Yet those who admit it put it expresly for a Space which essentially includes Parts and thus they put two contradictories nothing and parts that is parts and no parts or something and nothing in the same proposition And this I conceive to be absolutely unavoidable For these reasons therfore I must entreat my Readers favour that he will allow me to touch upon Metaphysicks a little more than I desire or intended but it shall be no otherwise then as is said of the Dogs by the River Nilus side who being thirsty lap hastily of the water only to serve their necessity as they run along the shore Thus then remembring how we determin'd that Quantity is Divisibility it follows that if besides Quantity there be a Substance or Thing which is divisible that Thing if it be condistinguish'd from its Quantity or Divisibility must of it self be indivisible or to speak more properly it must be not divisible Put then such Substance to be capable of the Quantity of the whole world or Universe and consequently you put it of it self indifferent to all and to any part of Quantity for in it by reason of the negation of Divisibility there is no variety of parts wherof one should be the subject of one part of Quantity or another of another or that one should be a capacity of more another of â—ess This then being so we have the ground of more or less Proportion between Substance and Quantity for if the whole Quantity of the Universe be put into it the proportion of Quantity â—o the capacity of that substance will be greater than if but half â—hat quantity were imbibed in the same substance And because proportion changes on both sides by the single change of only one side it follows that in the latter the proportion of that Substance to its Quantity is greater and that in the former 't is less though the Substance in it self be indivisible What we have said thus in abstract will sink more easily into us if we apply it to some particular bodies here among us in which we see a difference of Rarity and Density as to air water gold or the like and examine if the effects that happen to them do follow out of this disproportion between substance and Quantity For example let us conceive that all the quantity of the world were in one uniform substance then the whole universe would be of one and the same degree of Rarity and Density let that degree be the degree of water it will then follow that in what part soever there happens to be a change from this degree that part will not have that proportion of quantity to its substance which the quantity of the whole world had to the presupposed uniformsubstance But if it happens to have the degree of rarity which is in the air it will then have more quantity in proportion to its substance then would be due to it according to the presupposed proportion of the quantity of the universe to the aforesaid uniform substance which in this case is as it were the standard to try all other proportions by And contrariwise if it happens to have the degree of Density which is found in earth or in gold then it will have less quantity in proportion to its substance then would be due to it according to the aforesaid proportion or common standard Now to proceed from hence with examining the effects which result out of this compounding of Quantity with substance we may first consider that the Definitions which Aristotle has given us of Rarity and Density are the same we drive at He tells us that that body is rare whose quantity is more and its substance less that contrariwise dense where the substance is more and the quantity less Now if we look into the proprieties of the bodies we have named or of any others we shall see them all follow clearly out of these definitions For first that one is more diffused another more compacted such diffusion and compaction seem to be the very natures of Rarity and Density supposing them to be such as we have defined them to be since substance is more diffused by having more parts or by being in more parts and is more compacted by the contrary And then that rare bodies are more divisible then dense ones you see is coincident into the same conceit with their diffusion and compaction And from hence again it follows that they are more easily both divided into great and by the force of natural Agents divisible into lesser parts for both these that is facility of being divided and easie divisibility into lesser parts are contain'd in being more divisible or in more enjoying the effect of Quantity which is divisibility From this again follows that in rare bodies there is less resistance to the motion of another body through it than in dense ones and therefore a like force passes more easily through the one than through the other Again rare bodies are more penetrative and active than dense ones because being by their overproportion of quantity easily divisible into small parts they can run into every little pore and so incorporate themselvs better into other bodies than more dense ones can Light bodies likewise must be rarer because most divisible if other circumstances concur equally Thus you see decypher'd to your hand the first division of bodies flowing from Quantity as it is ordain'd to Substance for the composition of a Body for since the definition of a Body is a thing which hath parts and quantity is that by which it hath parts and the first propriety of quantity is to be bigger or lesse and consequently the first differences of having parts are to have bigger or lesse more or fewer what division of a Body can be more simple more plain or more immediate than to divide it by its Quantity as making it have bigger or less more or fewer parts in proportion to its Substance Neither can I justly be blamed for touching thus on Metaphysicks to explicate the nature of these two kinds of Bodies for Metaphysicks being the Science above Physicks it belongs to her to declare the principles of Physicks of which these we have now in hand are the very first step But much more if we consider that the composition of quantity with substance is purely Metaphysical we must necessarily allow the inquiry into the nature of Rarity and Density to be wholly Metaphysical since
other things be seen as being accompanied by light is called Fire What admits the illuminative action of fire and is not seen is called Air What admits the same action and is seen in the rank of Elements is called Water And what through the density of it admits not that action but absolutely reflects it is called Earth And out of all we said of these four Elements it is manifest there cannot be a fifth as is to be seen at large in every Aristotelian Philosopher that writes of this matter I am not ignorant that there are sundry objections used to be made both against these notions of the First Qualities and against the division of the Elements but because they and their solotions are to be found in every ordinary Philosopher and not of any great difficulty and that the handling them is too particular for the design of this discourse and would make it too prolix I refer the Reader to seek them for his satisfaction in those Authors that treat Physick professedly and have deliver'd a compleat body of Phylosophy And I will end this Chapter with advertising him lest I should be misunderstood that though my disquisition here has pitch'd on the four bodies of Fire Air Water and Earth yet it is not my intention to affirme that those which we ordinary call so and fall daily within our use are such as I have here express'd them or that these Phlosophicall ones which arise purely out of the combination of the first qualities have their residence or consistence in great bulks in any places of the World be they never so remote as Fire in the hollow of the Moons Orb Water in the bottom of the Sea Air above the Clouds and Earth below the Mines But these notions are onely to serve for certain Idea's of Elements by which the forenamed bodies and the compounds of them may be tryed and receive their doom of more or lesse pure and approaching to the nature from whence they have their denomination And yet I will not deny but that such perfect Elements may be foumd in some very little quantities in mixed bodies and the greatest abundance of them in these four known bodies that we call in ordinary practise by the names of the pure ones for they are least compounded and approach most to the simpleness of the Elements But to determine absolutely their existence or not existence either in bulk or in little parts depends of the manner of action among bodies which as yet we have not medled with CHAP. V. Of the operations of the Elements in general And of their activities compared with one another HAving by our former discourse inquired out what degrees and proportions of rarity and density compounded with gravity are necessary for the production of the Elements and first qualities whose combinations frame the Elements our next consideration in that orderly progress we have proposed to our selves in this Treatise wherein our aim is to follow successively the steps which nature has printed out to us will be to examine the operations of the Elements by which they work upon one another To which end let us propose to our selves a rare and a dense body encountring one another by the impulse of some exterior agent In this case 't is evident that since rarity implyes a greater proportion of quantity and quantity is nothing but divisibility rare bodies must needs be more divisible then dense ones and consequently when two such bodies are press'd one against another the rare body not being able to resist division so strongly as the dense one is and being not permitted to retire back by reason of the extern violence impelling it against the dense body it follows that the parts of the rare body must be sever'd to let the dense one come between them and so the rare body becomes divided and the dense body the divider And by this we see that the notions of divider and divisible immediately follow rare and dense bodies and so much the more properly agree to them as they exceed in the qualities of Rarity and Density Likewise we are to observe in our case that the dense or dividing body must necessarily cut and enter further and further into the rare or divided body and so the sides of it be joyn'd successively to new and new pars of the rare body that gives way to it and forsake others it parts from Now the rare body being in a determinate situation of the Universe which we call being in a place and is a necessary condition belonging to all particular bodies and the dense body comming to be within the rare body whereas formerly it was not so it follows that it loses the place it had and gains another This effect is that which we call local motion And thus we see by explicating the manner of this action that locall motion is nothing else but the change of that respect or relation which the body moved has to the rest of the Universe following out of Division and the name of Locall Motion formerly signifies only the mutation of a respect to other extrinsecall bodies subsequent to that division And this is so evident and agreeable to the notions that all mankind who as we have said is judge and master of language naturally frames of place as I wonder much why any will labour to give other artificall and intricate doctrine of this that in it self is so plain and clear What need is there to introduce an imaginary space or with Johannes Grammaticus a subsistent quantity that must run through all the World and then entail to every body an aiery entity an unconceiveable mood an unintelligible Ubi that by an intrinsecall relation to such a part of the imaginary space must thereto pin and fasten the body it is in It must needs be a ruinous Phylosophy that is grounded upon such a contradiction as is the allotting of parts to that which the Authors themselvs upon the matter acknowledge to be merely nothing and upon so weak a shift to deliver them from the inconveniences that in their course of doctrine other circumstances bring them to as is the voluntary creating of new imaginary Entities in things without any ground in nature for them Learned men should express the advantage and subtilty of their wits by penetrating further into nature then the vulgar not by vexing and wresting it from its own course They should refine and carry higher not contradict and destroy the notions of mankind in those things it is the competent judge of as it undoubtedly is of those primary notions which Aristotle has rank'd under Ten Heads which as we have touched before every one can conceive in gross and the work of Scholars is to explicate them in particular and not to make the Vulgar believe they are mistaken in framing those apprehensions that nature taught them Out of that which hath been hitherto resolvd 't is manifest that Place really and abstracting from
the operation of the understanding is nothing else but the inward superficies of a body that compasses and immediately conteines another Which ordinarily being of a rare body that doth not shew it self to us namely the Air is for the most part unknown by us But because nothing can make impression on our minds and cause us to give it a name otherwise then by being known therfore our understanding to make a compleat notion must add something else to this fleeting and unremarkable Superficies that may bring it to our acquaintance And for this end we may consider further that as this Superficies hath in it self so the bodie enclosed in it gains a certain determinate respect to the stable and immoveable bodies that environ it As for example we understand such a Tree to be in such a place by having such and such respects to such a Hill near it or to such a House that stands by it or to such a River that runs under it or to such an immoveable point of the Heaven that from the Suns rising in the Equinox is called East and such like To which purpose it imports not whether these that we call immoveable bodies and points be truly so or do but seem so to mankind For man talking of things according to the notions he frames of them in his mind speech being nothing else but an expression to another man of the images he hath within himself and his notions being made according to the seeming of the things he must needs make the same notions whether the things be truly so in themselvs or but seem to be so when that seeming or appearance is always constantly the same Now then when one body dividing another gets a new immediate clothing and consequently new respects to the stable and immoveable bodies or seeming such that environ it we vary in our selves the notion we first had of that thing conceiving it now accompanied with other circumstances and other respects then formerly it had Which notion we express by saying it has changed its place and is now no longer where it was at the first And this change of place we call Locall motion to wit the departing of a body from that hollow superficies which inclosed it and its changing to another wherby it gains new respects to those parts of the World that have or in some sort may seem to have immobility and fixed stableness So as hence 't is evident that the substance of Locall motion consists in Division and that the alteration of Locality follows Division in such sort as the becoming like or unlike of one wall to another follows the action whereby one of them becomes white And therefore in Nature we are to seek for any entity or special cause of applying the moved body to a place as place which is but a respect consequent to the effect of division but only to consider what real and physical action unites it to that other body which is called its place and truly serves for that effect And consequently they who think they have discover'd a notable subtilty by bringing in an Entity to unite a Body to its Place have strain'd beyond their strength and grasped but a shadow Which will appear yet more evident if they but mark well how nothing is divisible but what of it self abstracting from division is one For the nature of Division is the making of many which implies that what is to be divided must of necessity be not-many before it be divided Now Quantity being the subject of division 't is evident that purely of it self and without any force or adjoyned helps it must needs be one wherever some outward agent doth not introduce multiplicity upon it And whenever other things work upon quantity as quantity it is not the nature and power of their operation to produce unity in it and make it one for it is already one but contrariwise the immediate necessary effect that flows from them in this case is to make one quantity many according to the circumstances that accompany the divider and that which is to be divided And therefore although we may seek causes why some one thing sticks faster together then some other yet to ask absolutely why a body sticks together were prejudicial to the nature of quantity whose essence is to have parts sticking together or rather to have such unity as without which all divisibility must be excluded Out of which discourse it follows that in local motion we are to look onely for a cause or power to divide but not for any to unite For the very nature of quantity unites any two parts that are indistant from one another without needing any other cement to glue them together as we see the parts of water and all liquid substances presently unite themselves to other parts of like bodies when they meet with them and to solid bodies if they chance to be next them And therefore 't is vain to trouble our heads with Unions and imaginary Moods to unite a body to the place it is in when their own nature makes them one as soon as they are immediate to each other And accordingly if when we see a Boul move we would examine the causes of that motion we must consider the quantity of air or water it makes to break from the parts next to it to give place to it self and not speculate upon an intrinsecall relation from the body to a certain part of the imaginary space they will have to run through all things And by ballancing that quantity of air or water which it divides we may arrive to make an estimate of what force the Boul needs to have for its motion Thus having declar'd that the locality of motion is but an extrinsecall denomination and no reality in the thing moved we may now cast an eye upon a vast consequence that may be deduced out of what we have hitherto said For if we consider the nature of a Body that is that a Body is a Body by quantity and that the formall notion of Quantity is nothing else but Divisibility and that the adequate Act of Divisibility is Division 't is evident there can be no other Operation upon Quantity nor by consequence among Bodies but must either be such Division as we have here explicated or what must necessarily follow out of such division And Division as we have even now explicated being Locall Motion 't is evident that All operations among Bodies are either Local Motion or such as follow out of Local motion Which conclusion however unexpected and at first hearing appearing a Paradox will nevertheless by the ensuing work receive such evidence as it it cannot be doubted of and that not only by force of argumentation and by necessity of notions as is already reduced but also by experience and declaratiosns of particulars as they shall occur But now to apply what we have said to our proposed subject 't is obvious to every
man that seeing the Divider is the agent in division and in Local motion and dense bodies are by their nature dividers the Earth must in that regard be the most active among the Elements since it is the most dense of them all But this seems to be against the Common judgment of all the searchers of nature who unamimously agree that Fire is the most active Element As also it seems to impugne what we our selves have determin'd when we said there were two active qualities heat and cold whereof the first was in its greatest excess in Fire and the latter in water To reconcile these we are to consider that the action of Cold in its greatest height is composed of two parts the one is a kind of pressing and the other is penetration which requires applicability Of which two the former arises out of density but the latter out of moderation of density as I have declared in the precedent Chapter Wherefore the former will exceed more in Earth though the whole be more eminent in Water For though considering only the force of moving which is a a more simple and abstracted notion then the determination and particularization of the Elements and is precedent to it therein Earth hath a precedency over water yet taking the action as it is determin'd to be the action of a particular Element and as it concurs to the composition or dissolution of mixed bodies in that consideration which is the chief work of Elements and requires an intime application of the Agents Water hath the principality and excess over Earth As for Fire it is more active then either of them as will appear clearly if we consider how when Fire is applyed to fewel and the violence of blowing is added to its own motion it incorporates it self with the fewel and in a small time converts a great part of it into its own nature and shatters the rest into smoak and ashes All which proceeds from the exceeding smallness and dryness of the parts of fire which being moved with violence against the fewel and thronging in multitudes upon it easily pierce the porous substance of it like so many extreme sharp Needles And that the force of Fire is as great and greater then of Earth we may gather out of our former discourse where having resolved that density is the virtue by which a body is moved and cuts the medium and again considering that celerity of motion is a kind of density as we shall by and by declare 't is evident that since blowing must of necessity press violently and with a rapid motion the parts of fire against the fewel and so condense them exceedingly there both by their celerity by bringing very many parts together there it must needs also give them activity and vertue to pierce the body they are beaten against New that Celerity is a kind of Density will appear by comparing their natures For if we consider that a dense body may be dilated so as to possess and fill the place of a rare body that exceeded it in bigness and by that dilatation may be divided into as many and as great parts as the rare body was divisible into we may conceive that the substance of those parts was by a secret power of nature folded up in that little extension in which it was before And even so if we reflect upon two Rivers of equal channels and depths whereof the one goes swifter then the other and determine a certain length of each channel and a common measure of Time we shall see that in the same measure of time there passes a greater bulk of water in the designed part of the channel of the swifter stream then in the designed part of the flower though those parts be equal Nor imports it that in Velocity we take a part of time whereas in Density it seems that an instant is sufficient and consequently there would be no proportion between them For knowing Philosophers all agree that there are no Instants in time and that the apprehension of them proceeds meerly from the manner of our understanding And as for parts in time there cannot be assumed any so little in which the comparison is not true and so in this regard it is absolutely good And if the Reader have difficulty at the disparity of the things which are pressed together in Density and in Celerity for that in Density there is only Substance in Celerity there is also Quantity crowded up with the substence he will soon receive satisfaction when he shall consider that this disparity is to the advantage of what we say and makes the nature of density more perfect in celerity and consequently more powerful in fire then in earth Besides if there were no disparity it would be a distinct species of density but the very same By what we have spoken above it appears how fire gets into fewel now let us consider how it comes out for the activity of that fierce body will not let it lie still and rest as long as it has so many enemies round about it to rouse it up We see then that as soon as it has incoporated it self with the fewel and is grown master of it by introducing into it so many of its own parts like so many Souldiers into an Enemies Town they break out again on every side with as much violence as they came in For by reason of the former resistance of the fewel their continual streaming of new parts upon it and one overtaking another there where their journey was stop'd all which is increas'd by the blowing doth so exceedingly condense them into a narrower room then their nature effects that as soon as they get liberty and grow masters of the fewel which at the first was their prison they enlarge their place and consequently come out and flie abroad ever aiming right forwards from the point where they begin their journey for the violence wherewith they seek to extend themselves into a larger room when they have liberty to do so will admit no motion but the shortest which is by a straight line So that if in our phantasie we frame an image of a round body all of fire we must withall presently conceive that the flame proceeding from it would diffuse it self every way indifferently in straight lines so that the source serving for the Center there would be round about it an huge Sphere and of fire and light unless some accidental and extern cause should determine its motion more to one part then to another Which compass because it is round and has the figure of a Sphere is by Philosophers term'd the Sphere of its activity So that it is evident the most simple and primary motition of fire is a flux in a direct line from the center of it to its circumference taking the fewel for its center as also that when 't is beaten against a harder body it may be able to destroy it though that
is The better to apprehend how much this faint resemblance of flame upon the paper maketh for our purpose let us turn the leaf and imagine in our thoughts after what fashion that fire which is in the flame of a little candle would appear to us if it were dilated and stretch'd out to the utmost extent that excess of rarity can bring it to Suppose that so much flame as would fill a cone of two inches height and half an inch Diameter should suffer so great an expansion as to replenish with his light body a large chamber and then what can we imagine it would seem to be How would the continual driving it into a thinner substance as it streams in a perpetual flood from the flame seem to play upon the paper And then judg whether it be likely to be a body or no when our discourse suggests to us that if it be a body those very appearances must follow which our eyes give us evidence are so in effect If gold beaten into so airy a thinness as we see gilders use remains still Gold notwithstanding the wonderfull expansion of it why shall we not allow that fire dilated to its utmost period shall still remain fire though extreamly rarified beyond what it was We know that fire is the rarest and the subtilest substance that nature hath made among bodies and we know likewise that it is ingendred by the destroying and feeding upon some other more grosse body let us then calculate when the oyl or tallow or wax of a candle or the bulk of a faggot or billet is dilated and rarified to the degree of fire how vast a place must it take up To this let us add what Aristotle teaches us that fire is not like a standing pool which continues full with the same water and as it has no waste so has it no supply but it is a fluent and brook-like current Which also we may learn out of the perpetual nutriment it requires for a new part of fewel being converted into a new part of fire as we may observe in the little atomes of Oyl or melted wax that continually ascend apace up the wieke of a burning candle or lamp of necessity the former must be gone to make room for the latter and so a new part of the river is continually flowing Now then this perpetual flux of fire being made of a grosse body that so rarified will take up such a vast room if it die not at the instant of its birth but have some time to subsist be it never so short it must needs run some distance from the fountain whence it springs Which if it do you need not wonder that there should be so great an extent of fire as is requisite to fill all that space which light replenishes nor that it should be still supplyed with new as fast as the cold of the aire kills it For considering that flame is a much grosser substance then grosse fire by reason of the mixture with it of that viscous oyly matter which being drawn out of the wood and candle serves for fewel to the fire and is by little and little converted into it and withal reflecting on the nature and motion of fire which is to dilate it self extreamly and to fly all about from the center to the circumference you cannot choose but conceive that the pure fire strugling to break away from the oyly fewel which is still turning into new fire doth at length free his wings from that birdlime and then flies abroad with extream swiftness swels and dilates it self to a huge bulk now that it has gotten liberty and so fills a vast room but remains still fire till it die Which it no sooner doth but it is still supply'd with new streams of it that are continually strain'd as it were squees'd out of the thick flame which imprison'd and kept it within it till growing fuller of fire then it could contain by reason of the continual attenuating the oyly parts of it and converting them into fire it gives liberty to those parts of fire that are next the superficies to fly whither their nature will carry them And thus discourse would inform a Blind man after he has well reflected on the nature of fire how it must needs fill a mighty extent of place though it have but a narrow beginning at its spring head and that there by reason of the condensation of it and mixture with a grosser body it must needs burn other bodies but that when it is freed from such mixture and suffers an extream expansion it cannot have force to burn but may have means to express it self to be there present by some operation of it upon some body that is refin'd and subtilized enough to perceive it And this operation a seeing man will tell you is done upon his eyes whose fitness to receive impression from so subtile an Agent Anatomists will teach you And I remember how a blind Schoolmaster that I kept in my house to teach my children who had extream subtile spirits and a great tenderness through his whole body and met with few distractions to hinder him from observing any impression never so nicely made upon him used often to tell me that he felt it very perceptibly in several parts of his body but especially in his brain But to settle us more firmly in the perswasion of light 's being a body and consequently fire let us consider that the properties of a body are perpetually incident to light look what rules a ball will keep in its rebounds the same doth light in its reflections and the same demonstration alike convinces the one and the other Besides light is broken like a body as when 't is snapped in pieces by a tougher body it is gather'd together in a little room by looking or burning glasses as water is by ordering the gutters of a house so as to bring into one cistern all that rains dispersedly upon the whole roof It is sever'd and dispers'd by other glasses and is to be wrought upon and cast hither and thither at pleasure all by the rule of other bodies And what is done in light the same will likewise be done in heat in cold in wind and in sound And the very same instruments that are made for light will work their effects in all these others if they be duly managed So that certainly were it not for the authority of Aristotle and his learned followers that presses us on the one side and for the seemingness of those reasons we have already mention'd which perswades us on the other side our very eyes would carry us by stream into this consent that light is no other thing but the nature and substance of fire spread far and wide and freed from the mixture of all other gross bodies Which will appear yet more evident in the solutions of the oppositions we have brought against our own opinion for in them there will
of fewel to maintain the same light for a great company of years But I should not easily be perswaded that either flame or light could be made without any manner of consuming the body which serves them for fewel CHAP. VIII An Answer to three other Objectious formerly proposed against Light being a Substance HAving thus defended our selves from their Objections who would not allow light to be fire and having satisfied their inquisition who would know what becomes of it when it dyes if it be a body we will now apply our selves to answer their difficulties who will not let it pass for a body because it is in the same place with another body as when the Sun-beams enlighten all the air and when the several lights of two distinct Candles are both of them every where in the same room Which is the substance of the second main objection This of the justling of the aire is easily answered thus that the aire being a very divisible body doth without resistance yield as much place as is requisite for light And that light though our eyes judge it diffused every where yet is not truly in every point or atome of air but to make us see it every where it suffices that it be in every part of the air which is as big as the black or sight of our eye so that we cannot set our eye in any position where it receives not impressions of light In the same manner as Perfumes which though they be so gross bodies that they may be sensibly wasted by the wind yet â—o fill the air that we can put our nose in no part of the room where a perfume is burned but we shall smell it And the like is of mists as also of the sprouted water to make a perfume which we mention'd above But because pure discourses in such small thrids as these 〈◊〉 but weakly bind such Readers as are not accustom'd to them and I would if possible render this Treatise intelligible to every rational man how ever little vers'd in Scholastick learning among whom I expect it will have a fairer passage then among those that are already deeply imbued with other principles let us try if we can herein inform our selves by our sense and bring our eyes for witness of what we say He then that is desirous to satisfie himself in this particular may put himself in a dark room through which the Sun sends his beams by a cranie or little hole in the wall and he will discover a multitude of little atomes flying about in that little stream of light which his eye cannot discern when he is environ'd on all sides with a full light Then let him examine whether or no there be light in the midst of those little bodies and his own reason will easily till him that if those bodies were as perspicuous as the air they would not reflect upon our eyes the beams by which we see them And therefore he will boldly conclude that at the least such parts of them as reflect light to us do not admit it nor let it sink into them Then let him consider the multitude of them and the little distance betwixt one another and how nevertheless they hinder not our sight but we have it free to discover all objects beyond them in what position soever we place our eye And when he thus perceives that these opacous bodies which are every where do not hinder the eye from judging light to have an equal plenary diffusion through the whole place that it irradiates he can have no difficulty to allow air that is diaphanous and more subtile far then they and consequently divisible into lesser atomes and having lesser pores gives less scope to our eyes to miss light then they do to be every where mingled with light though we see nothing but light and cannot discern any breach of it Especially when he shall adde to this consideration that the subtile body which thus fills the air is the most visible thing in the world and that whereby all other things are seen and that the air it mingles it self with is not at all visible by reason of the extreme diaphaneity of it and easie reception of the light in every pore of it without any resistance or reflection and that such is the nature of light as it easily drowns an obscure body if it be not too big and not onely such but even other light bodies for so we know as well the fixed Stars as the Planets are conceal'd from our sight by the nearness to the Sun neither the lightness of the one nor the bigness of the other prevailing against the darkning of an exuperant light and we have daily experience of the same in very pure chrystal glasses and in very clear water which though we cannot discern by our sight if they be certain positions nevertheless by experience we find that they reflect much light and consequently have great store of opacous parts And then he cannot choose but conclude that it is impossible but light should appear as it doth to be every where and to be one continued thing though his discourse withal assure him it is every where mingled with air And this very answer I think will draw with it by consequence the solution of the other part of the same objection which is of many lights joyning in the same place and the same is likewise concerning the images of colours every where crossing one another without hindrance But to raise this contemplation a strain higher let us consider how light being the most rare of all known bodies is of its own nature by reason of the divisibility that followeth rarity divisible into lesser parts then any other and particularly then flame which being mixed with smoke and other corpulency falls very short of light And this to the proportion in which it is more rare then the body 't is compared to Now a great Mathematician having devised how to measure the rarefaction of Gun-powder into flame found the Diameter fifty times increased and so concluded that the body of the flame was in proportion to the body of the Gun-powder it was made of as 125000. is to one Wherfore by the immediately proceeding consequence we find that 125000 parts of flame may be couched in the room of one least part of gunpowder and peradventure many more considering how porous a body Gun-powder is Which being admitted 't is evident that although light were as gross as the flame of Gun-powder and Gun-powder were as solid as gold yet there might pass 125000. rayes of light in the space wherin one least part of Gun-powder might be contained which space would be absolutely invisible to us and be contained many times in the bigness of the sight of a mans eye Out of which we may gather what an infinity of objects may seem to us to cross themselvs in the same indivisible place and yet may have room sufficient for every one
to pass his way without hindring his fellow Wherfore seeing that one single light could not send rayes enough to fil every little space of aire that is capable of light and the less the further it is from the flame 't is obvious enough to conceive how in the space where the air is there is capacity for the rays of many candles Which being well sum'd up will take away the great admiration how the beams of light though they be corporeall can in such great multitudes without hindering one another enter into bodies and come to our eye and will shew that 't is the narrowness of our capacities and not the defect of nature which makes these difficulties seem so great For she hath sufficiently provided for all these subtile operations of fire as also for the entrance of it into glass and into all other solid bodies that are Diaphanous upon which was grounded the last instance the second objection pressed for all such bodies being constituted by the operation of fire which is alwaies in motion there must needs be ways left for it both to enter in and to evaporate out And this is most evident in glass which being wrought by an extreme violent fire and swelling with it as water and other things do by the mixture of fire must necessarily have great store fire in it self whiles it is boyling as we see by its being red hot And hence it is that the workmen are forced to let it cool by degrees in such relentings of fire as they call their nealing heats lest it should shiver in pieces by a violent succeeding of air in the room of the fire for that being of greater parts then the fire would strain the pore of the glass too suddenly and break it all in pieces to get ingressions whereas in those nealing heats the air being rarer lesser parts of it succeed to the fire and leisurely stretch the pores without hurt And therefore we need not wonder that light passes so easily through glass and much less that it gets through other bodies seeing the experience of Alchymists assures us 't is hard to find any other body so impenitrable as glass But now to come to the answer of the first and in appearance most powerful objection against the corporeity of light which urges that its motion is perform'd in an instant and therefore cannot belong to what is material and cloth'd with quantity We will endeavour to shew how unable the sense is to judge of sundry sorts of motions of Bodies and how grosly it is mistaken in them And then when it shall appear that the motion of light must necessarily be harder to be observed then those others I conceive all that is rais'd against our opinion by so incompetent a judge will fall flat to the ground First then let me put the Reader in mind how if ever he mark'd children when they play with firesticks they move and whirle them round so fast that the motion will cosen their eyes and represent an entire circle of Fire to them and were it somewhat distant in a dark night that one play'd so with a lighted Torck it would appear a constant Wheele of fire without any discerning of motion in it And then let him consider how slow a motion that is in respect of what 't is possible a body may participate of and he may safely conclude that 't is no wonder though the motion of light be not descried and that indeed no argument can be made from thence to prove that light is not a body But let us examine this consideration a little further and compare it to the motion of the earth or heavens Let the appearing circle of the fire be some three foot Diameter and the time of one entire circulation of it be the sixtieth part of a minute of which minutes there are 60. in an hour so that in a whole day there will but be 86400. of these parts of time Now the Diameter of the wheel of fire being but of three foot the whole quantity of space that it moves in that atome of time will be at the most ten foot which is three paces and a foot of which parts there are near eleven millions in the compass of the earth so that if the earth be moved round in 24. hours it must go near 130. times as fast as the Boy 's stick which by its swift motion deceives our eye But if we allow the Sun the Moon and the fixed Stars to move how extreme swift must their flight be and how imperceptible would their motion be in such a compass as our sight would reach to And this being certain that whether the earth or they move the appearances to us are the same 't is evident that as now they cannot be perceiv'd to move as peradventure they do not so it would be the very same in shew to us although they did move If the Sun were near us and gallop'd at that rate surely we could not distinguish between the beginning and ending of his race but there would appear one permanent Line of light from East to West without any motion at all as the Torch seems to make with so much a slower motion one permanent immoveable wheel of fire But contrary to this effect we see that the Sun and Stars by onely being removed further from our eyes do cosen our sight so grossely that we cannot discern them to be moved at all One would imagine that so rapid and swift a motion should be perceiv'd in some sort or other which whether it be in the earth or in them is all one to this purpose Either we should see them change their places whiles we look upon them as Arrows and Birds do when they fly in the Aire or else they should make a stream of light bigger then themselvs as the Torch doth But none of all this happens Let us gaze upon them so long and so attentively that our eyes be dazled with looking and all that while they seem to stand immovable and our eyes can give us no account of their journey till it be ended They discern it not while it is in doing So that if we consult with no better counsellour then them we may wonder to see that body at night setting in the West which in the morning we beheld rising in the East But that which seems to be yet more strange is that these bodies move cross us and nevertheless are not perceiv'd to have any motion at all Consider then how much easier it is for a thing that moves towards us to be with us before we are aware A nimble Fencer will put in a thrust so quick that the â—oil will be in your bosome when you thought it a yard off because in the same moment you saw his point so far distant and could not discerne it to move towards you till you felt the rude salutation it gave you If then you will compare the body of light with
to which much more might be added but that we have already trespassed in length and I conceive enough is said to decide the matter an equal judge will find the ballance of the question to hang upon these termes that to prove the nature of light to be material corporeal are brought a company of accidents well known to be the proprieties of quantitie or bodies and as well known to be in light Even so far as that 't is manifest light in its beginning before it be dispersed is fire and if again it be gathered together it shews it self again to be fire And the receptacles of it are the receptacles of a body being a multitude of pores as the hardness and coldness of transparent things do give us to understand of which we shall hereafter have occasion to discourse On the contrary side whatever arguments are brought against lights being a body are only negative As that we see not any motion of light that we do not discern where the confines are between light and air that we see not room for both of them or for more lights to be together and the like which is to oppose negative proofs against affirmative ones and to build a doctrine upon the defect of our senses or upon the likeness of bodies which are extremely unlike expecting the same effects from the most subtile as from the most gross ones All which together with the authority of Aristotle his followers have turned light into darkness and made us almost deny the light of our own eyes Now then to take our leave of this important question let us return to the principles from whence we began and consider that Seeing Fire is the most rare of the Elements and very dry and that out of the former it hath that it may be cut into very small pieces and out of the later that it conserves its own figure and so is apt to divide what ever fluid body and joyning to these two principles that it multiplies extremely in its source It must of necessity follow that it sends out in great multitudes little small parts into the air and other bodies circumfused with great dilatation in a spherical manner And likewise that these little parts are easily broken and new ones still following the former are still multiplyed in straight lines from the place where they break Out of which 't is evident that of necessity it must in a manner fill all places and that no sensible place is so little but that fire wil be found in it if the medium be capacious As also that its extreme least parts will be very easily swallow'd up in the parts of the air which are humid and by their enfolding be as it were quite lost so as to lose the appearance of fire Again that in its reflections it will follow the nature of grosser bodies and have glidings like them which is that we call refractions That little streamings from it will cross one another in excessive great numbers in an unsensible part of space without hindering one another That its motion will be quicker then sense can judge of and therefore will seem to move in an instant or to stand still as in a stagnation That if there be any bodies so porous with little and thick pores as that the pores arrive near to equalling the substance of the body then such a body will be so fill'd with these little particles of fire that it will appear as if there were no stop in its passage but were all filled with fire and yet many of these little parts will be reflected And whatever qualities else we find in light we shall be able to derive them out of these principles and shew that fire must of necessity do what experience teaches us that light doth That is to say in one word it will shew us that fire is light But if fire be light then light must needs be fire And so we leave this matter CHAP. IX Of Local motion in common THough in the fifth Chapter we made only earth the pretender in the controversie aginst fire for superiority in activity and in very truth the greatest force of gravity appears in those bodies which are eminently earthy nevertheless both water and air as appears out of the 4. Chapter of the Elements do agree with earth in having gravity and gravity is the chief virtue to make them efficients So that upon the matter this plea is common to all the three Elements Wherfore to explicate this virtue wherby these three weighty Elements work let us call to mind what we said in the beginning of the last Chapter concerning local motion to wit that according as the body moved or the divider did more and more enter into the divided body so it joyn'd it self to some new parts of the Medium or divided body and did in like manner forsake others Whence it happens that in every part of motion it possesses a greater part of the Medium then it self can fill at once And because by the limitation and confinedness of every magnitude to just what it is and no more 't is impossible that a lesser body should at once equalize a greater it followes that this division or motion whereby a body attains to fill a place bigger then it self must be done successively that is it must first fill one part of the place it moves in then another and so proceed on till it have measur'd it self with every part of the place from the first beginning of the line of motion to the last period of it where the body rests By which discourse it is evident that there cannot in nature be a strength so great as to make the least or quickest moveable that is to pass in an instant or all together over the least place that can be imagin'd for that would make the moved body remaining what it is in regard of its bigness to equallize and fit a thing bigger then it is Therfore it is manifest that motion must consist of such parts as have this nature that whiles one of them is in being the others are not yet and as by degrees every new one comes to be all the others that were before do vanish and cease to be Which circumstance accompanying motion we call Succession And whatever is so done is said to be done in time which is the common measure of all succession For the change of situation of the Stars but especally of the Sun and Moon is observ'd more or less by all mankind and appears alike to every man and being the most known constant and uniform succession that men are used to is as it were by nature it self set in their way and offer'd them as fittest to estimate and judge all other particular successions by comparing them both to it and among themselves by it And accordingly we see all men naturally measure all other successions and express their quantities by comparing them to the
by descending so that as long as it boyls 't is in a perpetual confused motion up and down Now having formerly concluded that fire is light and light is fire it cannot be doubted but that the Sun serves instead of fire to our Globe of Earth and water which may be fitly compared to the boyling pot and all the day long draws vapours from those bodies that his beams strike upon For he shooting his little darts of fire in multitudes and in continued streams from his own center against the Python the earth we live on they there overtake one another and cause some degrees of heat as far as they sink in But not being able by reason of their great expansion in their long journey to convert it into their own nature and set it on fire which requires a high degree of condensation of the beams they but pierce and divide it very subtilly and cut some of the outwardparts of it into extreme little atomes To which sticking very close and being in a manner incorporated with them by reason of the moisture that is in them they in their rebound back from the earth carry them along with them like a ball that struck against a moist wall in its return from it brings back some of the mortar sticking upon it For the distance of the Earth from the Sun is not the utmost period of these nimble bodie 's flight so that when by this solid body they are stop'd in their course forwards on they leap back from it and carry some little parts of it with them som of them a farther some of them a shorter journey according to their littleness and rarity make them fit to ascend As is manifest by the consent of all Authors that write of the Regions of the Air who determine the Lower Region to reach as far as the reflection of the Sun and conclude this Region to be very hot For if we mark how the heat of fire is greatest when it is incorporated in some dense body as in Iron or in Sea-coal we shall easily conceive that the heat of this Region proceeds mainly out of the incorporation of light with those little bodies which stick to it in its reflection And experience testifies the same both in our soultry days which we see are of a gross temper and ordinarily go before rain as also in the hot Springs of extreme cold countrys where the first heats are unsufferable which proceed out of the resolution of humidity congeal'd in hot winds which the Spaniards call Bochornos from Boca de horno by allusion to the breathing stream of an Oven when it is open'd which manifestly shew that the heat of the Sun is incorporated in the little bodies which compose the steam of that wind And by the principles we have already laid the same would be evident though we had no experience to instruct us for seeing that the body of fire is dry the wet parts which are easiest resolved by fire must needs stick to them and accompany them in their return from the earth Now whiles these ascend the air must needs cause others that are of a grosser complexion to descend as fast to make room for the former and to fill the places they left that there may be no vacuity in nature And to find what parts they are and from whence they come that succeed in the room of light and atomes glew'd together that thus ascend we may take a hint from the Maxime of the Opticks that Light reflecting makes equal angles whence supposing the Superficies of the earth to be circular it will follow that a Perpendicular to the center passes just in the middle between the two rayes the incident and the reflected Wherefore the air between these two rayes and such bodies as are in it being equally pressed on both sides those bodies which are just in the middle are nearest and likeliest to succeed immediately in the room of the light and atomes which ascend from the Superficies of the earth and their motion to that point is upon the Perpendicular Hence 't is evident that the Air and all such bodies as descend to supply the place of light and atomes which ascend from the Earth descend perpendicularly towards the center of the earth And again such bodies as by the force of light being cut from the earth or water do not ascend in form of light but incorporate a hidden light and heat within them and thereby are rarer then these descending bodies must of necessity be lifted up by the descent of those denser bodies that go downwards because they by reason of their density are moved with a greater force And this lifting up must be in a perpendicular line because the others descending on all sides perpendicularly must needs raise those that are between them equally from all sides that is perpendicularly from the center of the earth And thus we see a motion set on foot of some bodies continually descending and others continually ascending all in perpendicular lines excepting those which follow the course of lights reflexion Again as soon as the declining Sun grows weaker or leaves our Horizon and his beams vanishing leave the little hors-men which rode upon them to their own temper and nature from whence they forced them they finding themselvs surrounded by a smart descending stream tumble down again in the night as fast as in the day they were carried up and crowding into their former habitations exclude those they find had usurped them in their absence And thus all bodies within reach of the Suns power but especially our air are in perpetual motion the more rarified ones ascending and the dense ones descending Now then because no bodies wherever they be as we have already shew'd have any inclination to move towards a particular place otherwise then as they are directed and impel'd by extrinsecal Agents let us suppose that a body were placed at liberty in the open air And then casting whether it would be moved from the place we suppose it in and which way it would be moved we shall find it must of necessity happen that it shall descend and fall down till it meet with some other gross body to stay and support it For though of it self it would move no way yet if we find that any other body strikes efficaciously enough upon it we cannot doubt but it will move that way which the striking body impels it Now it is strucken upon on both sides above and below by the ascending and the descending atoms the rare ones striking upon the bottome of it and driving it upwards and the denser ones pressing upon the top of it and bearing it downwards But if you compare the the impressions the denser atoms make with those that proceed from the rare ones 't is evident the dense ones must be the more powerful and therfore will assuredly determine the motion of the body in the air that way they go which is
downwards Nor need we fear lest the littlenessof the agents or the feebleness of their stroaks should not be sufficient to work this effect since there is no resistance in the body it self and the air is continually cut in pieces by the Sun-beams and by the motions of little bodies so that the adhesion to air of the body to be moved will be no hind'rance to this motion especially considering the perpetual new percussions and the multitude of them and how no force is so little but that with time and multiplication it will overcome any resistance But if any man desires to look on as it were at one view the whole chain of this doctrine of Gravity let him turn the first cast of his eyes on what we have said of fire when we explicated the nature of it To wit that it begins from a little source and by extreme multiplication and rarefaction extends it self into a great sphere And then hee 's perceive the reason why light is darted from the body of the Sun with that incredible celerity wherewith its beams fly to visit the remotest parts of the world and how of necessity it gives motion to all circumstant bodies since it is violently thrust forward by so extreme rarefaction and the further it goes is still the more rarified and dilated Next let him reflect how infinitely the quickness of lights motion prevents the motion of a moist body such an one as air is and then he wil plainly see that the first motion which light is able to give the air must needs be a swelling of that moist element perpendicularly round about the earth For the ray descendent and the ray reflectent flying with so great a speed that the air between them cannot take a formal pley any way before the beams of light be on both sides of it it followes that according to the nature of humide things it must first only swell for that is the beginning of motion in them when heat enters into and works on them And thus he may confidently resolve himself that the first motion which light causes in the air will be a swelling of it between the two rays towards the middle of them That is perpendicularly from the surface of the earth And out of this he will likewise plainly see that if there be any other little dense bodies floating in the air they must likewise mount a little through this swelling and rising of the air But that mounting will be no more then the immediate parts of the air themselvs move Because this motion is not by way of impulse or stroke that the air gives those denser bodies but by way of containing them in it and carrying them with it so that it gives them no more celerity then to make them go with it self and as parts of it self Then let him consider that light or fire by much beating upon the earth divides some little parts of it from others wherof if any become so small and tractable as not to exceed the strength which the rays have to manage them the returning rays will at their going back carry away with or drive before them such little atomes as they made or met with and so fill the air with little bodies cut out of the earth After this let him consider that when light caries up an atome with it the light and the atome stick together and make one ascending body in such sort as when an empty dish lies upon the water the air in the dish makes one descendent body together with the dish it self so that the density of the whole body of air and dish which in this case are but as one body is to be esteem'd according to the density of the two parts one of them being allay'd by the other as if the whole where thrughout of such a proportion of density as would arise out of the composition and kneading together the several densities of those two parts Now then when these little compounded bodies of light and earth are carryed up to a determinate height the parts of fire or light by little and little break away from them and therby the bulk of the part which is left becoms of a different degree of density quantity for quantity from the bulk of the entire atome when light was part of it and consequently it is denser then it was Besides let him consider that when these bodies ascend they go from a narrow room to a large one that is from the centrewards to the circumference but when they come down again they go from a larger part to a narrower Whence it followes that as they descend they draw closer and closer together and by consequence are subject to meet and fall in one with another and therby to increase their bulk and become more powerful in density not only by the loss of their fire but also by the encrease of their quantity And so 't is evident that they are denser coming down then going up Lastly let him consider that those atoms which went up first and are parted from their volative companions of fire or light must begin to come down apace when other new atoms which still have their light incorporated with them ascend to where they are and go beyond them by reason of their greater levity And as the latter atoms come up with a violence and great celerity so must the first go down with a smart impulse and by consequence being more dense then the air in which they are carryed must of necessity cut their way through that liquid and rare Medium and go the next way to supply the defect and room of the atoms which ascend that is perpendicularly to the earth and give the like motion to any body they find in their way if it be susceptible of such a motion Which 't is evident that all bodies are unless they be strucken by some contrary impulse For since a bodies being in a place is nothing else but the continuity of its outside to the inside of the body that contains it and is its place it can have no other repugnance to local motion which is nothing else but a successive changing of place besides this continuity Now the nature of density being the power of dividing and every least power having some force efficacy as we have shew'd above it follows that the stroke of every atome either descending or ascending will work somthing upon any body though never so big it chances to incounter with and strike upon in its way unless there be as strong an impulse the contrary way to oppose it But it being determin'd that the descending atoms are denser then those that ascend it follows that the descending ones will prevail And consequently all dense bodies must necessarily tend downwards to the center which is to be heavy if some other more dense body do not hinder them Out of this discourse we may conclude that there is no such thing among bodies
an aptitude the better to cut the medium and from the mltitude of little atomes descending that strike upon it and press it the way they go which is downwards then it would not import whether the inner part of that body were as solid as the outward parts for it cuts with only the outward and is smitten only upon the outward And yet experience shews us the contrary for a great bullet of lead that is solid and lead throughout descends faster then if three quarters of the Diameiter were hollow within and such a one falling upon any resisting substance works a greater effect then a hollow one And a ball of brass that hath but a thin outside of metal will swim upon the water when a massie one sinks presently Whereby it appears that it is rather some other quality belonging to the very bulk of the metal in it self and not these outward causes that occasion gravity But this difficulty is easily overcome if you consider how subtile those atomes are which descending downwards striking upon a body in their way cause its motion likewise downwards for you may remember how we have shew'd them to be the subtilest and the minutest divisions that Light the subtilest and sharpest divider in nature can make It is then easie to conceive that these extreme subtile bodies penetrate all others as light doth glass and run through them as sand through a small sieve or as water through a spunge so that they strike not only upon the Superficies but as well in every most interiour part of the whole body running quite through it all by the pores of it And then it must needs follow that the solider it is and the more parts it has within as well as without to be strucken upon the faster it go and the greater effect it must work in what falls upon whereas if three quarters of the Diameter of it within should be fill'd with nothing but air the atoms would fly without any considerable effect through all that space by reason of the rarity cessibility of it And that these atoms are thus subtile is manifest by several effects which we see in nature Divers Authors that write of Egypt assure us that though their houses be built of strong stone nevertheless a clod of earth laid in the inmost rooms and shut up from all appearing communication with air will encrease its weight so notably as therby they can judge the change of weather which will shortly ensue Which can proceed from no other cause but a multitde of little atoms of Saltpeter which floating in the air penetrate through the strongest wals and all the massie defences in their way and settle in the cold of earth as soon as they meet with it because it is of a temper fit to entertain and conserve embody them Delights have shewed us the way how to make the spirits or atoms of Snow and Saltpeter pass through a glass vessel which Alchimists hold to be the most impenetrable of all they can find to work with In our own bodies the aches which feeble parts feel before change of weather and the heaviness of our heads and shoulders if we remain in the open air presently after sunset abundantly testifie that even the grosser of these atoms which are the first that fall do vehemently penetrate our bodies so as sense will make us believe what reason peradventure could not But besides all this there is yet a more convincing reason why the descending atomes should move the whole density of a body even though it were so dense that they could not penetrate it and get into the bowels of it but must be content to strike barely upon the outside of it For nature has so order'd the matter that when dense parts stick close together and make the length composed of them to be very stiff one cannot be moved but that all the rest which are in that line must likewise be thereby moved so that if all the world were composed of atoms closse sticking together the least motion imaginable must drive on all that were in a straight line to the very end of the world This you see is evident in reason and experience confirms it when by a little knock given at the end of a long beam the shaking which makes sound reaches sensibly to the other end The blind man that governs his steps by feeling in defect of eyes receives advertisements of remote things through a staff which he holdeth in his hands peradventure more particularly then his eyes could have directed him And the like is of a deaf man that hears the sound of an Instrument by holding one end of a stick in his mouth whiles the other end rests upon the Instrument And some are of opinion and they not of the rank of vulgar Philosophers that if a staff were as long as to reach from the Sun to us it would have the same effect in a moment of time Although for my part I am hard to believe we could receive an advertisement so far unless the staff were of such a thickness as being proportionable to the length might keep it from facile bending for if it should be very plyant it would do us no service as we experience in a thrid which reaching from our hand to the ground if it knock against any thing makes no sensible impression in our hand So that in fine reason sense and authority all of them shew us that the less the atomes should penetrate into a moving body by reason of the extreme density of it the more efficaciously they would work and the greater celerity they would cause in its motion And hence we may give the fullest solution to the objection above Which was to this effect that seeing division is made only by the superficies or exteriour part of the dense body and the virtue whereby a dense body works is onely its resistance to division which makes it apt to divide it would follow that a hollow bowl of brass or iron should be as heavy as a solid one For we may answer that seeing the atoms must strike through the body and a cessible body doth not receive their strokes so firmly as a stiffe one nor can convey them so far if to a stiff superficies there succeed a yielding inside the strokes must of necessity lose much of their force and consequently cannot move a body full of air with so much celerity or with so much efficacy as they may a solid one But then you may peradventure say that if these strokes of the descending atomes upon a dense body were the cause of its motion downwards we must allow the atomes to move faster then the dense body that so they may still overtake it and drive it along and enter into it whereas if they should move slower then it none of them could come in their turn to give it a stroke but it would be past them and out of their reach before they
could strike it But it is evident say you out of these pretended causes of this motion that such atomes cannot move so swiftly downwards as a great dense body since their littleness and their rarity are both of them hindering to their motion Therefore this cannot be cause of that effect which we call gravity To this I reply That to have the atoms give these blows to a descending dense body 't is not requir'd that their natural and ordinary motion should be swifter then the descent of such a dense body but the very descent of it occasions their striking it for as it falls and makes it self a way through them they divide themselves before it and swell on the sides and a little above it and presently close again behind it and over it assoon as it is past Now that closing to hinder vacuity of space is a sudden one and thereby attains great velocity which would carry the atoms in that degree of velocity further than the descending body if they did not encounter with it in their way to retard them which encounter and tarding implyes such strokes upon the dense body as we suppose to cause this motion And the like we see in water into which letting a stone fall presently the water that was divided by the stone and swells on the sides higher then it was before closes upon the back of the descending stone and follows it so violently that for a while after it leaves a purling hole in the place where the stone went down till by the repose of the stone the water returns likewise to its quiet and so its superficies becomes even In the third place an enquiry occurs emergent out of this doctrine of the cause of bodies moving upwards and downwards Which is Whether there would be any natural motion deep in the earth beyond the activity of the Sun beams for out of these principles it follows that there would not and consequently there must be a vast Orb in which there would be no motion of gravity or levity For suppose the Sun beams might pierce a thousand miles deep into the body of the earth yet there would still remain a mass whose Diameter would be near 5000 miles in which there would be no gravitation nor the contrary motion For my part I shall make no difficulty to grant the inference as far as concerns motion caused by our Sun for what inconvenience would follow out of it But I will not offer at determining whether there may not be enclosed within that great sphere of earth some other fire such as the Chymists talk of an Archeus a Demogorgon seated in the centre like the heart in animals which may raise up vapours and boyl an air out of them and divide gross bodies into atoms and accordingly give them motions answerable to ours but in different lines from ours according as that fire or Sun is situated Since the far-searching Authour of the Dialogues de Mundo hath left that speculation undecided after he had touched upon it in the Twelfth knot of his first Dialogue Fourthly it may be objected that if such descending atoms as we have described were the cause of a bodies gravity and descending towards the center the same body would at divers times descend more and less swiftly for example after midnight when the atoms begin to descend more slowly the same body would descend more slowly in a like proportion and not weigh so much as it did in the heat of the day The same may be said of Summer and Winter for in Winter time the atoms seem to be more gross and consequently to strike more strongly upon the bodies they meet with in their way as they descend yet on the other side they seem in the Summer to be more numerous as also to descend from a greater height both which circumstances will be cause of a stronger stroke and more vigorous impulse on the body they hit And the like may be objected of divers parts of the World for in the Torrid Zone it will always happen as in Summer in places of the Temperate Zone and in the Polar times as in deepest winter so that no where there should be any standard or certainty in the weight of bodies if it depended upon so mutable a cause And it makes to the same effect that a body which lies under a thick rock or any other very dense body that cannot be penetrated by any great store of atoms should not be so heavy as it would be in the open and free air where the atoms in their compleat numbers have their full strokes For answer to these and such like instances we are to note first that 't is not so much the number or violence of the percussion of the striking atoms as the density of the thing strucken which gives the measure to the descending of a weighty body and the chief thing which the stroak of the atoms gives to a dense body is a determination of the way which a dense body is to cut to it self therfore multiplication or lessening of the atoms will not make any sensible difference betwixt the weight of one dense body where manya toms strike and an other body of the same density where but a few strike so that the stroak downwards of the descending atoms be greater then the stroke upwards of the ascending atoms and therby determines it to weigh to the Centrewards and not rise floating upwards which is all the sensible effect we can perceive Next we may observe that the first particulars of the objection do not reach home to enfeeble our doctrine in this particular although we admit them to be in such sort as they are proposed for they withal imply such a perpetual variation of causes ever favourable to our position that nothing can be infer'd out of them to repugne against it As thus When there are many atoms descending in the air the same general cause which makes them be many makes them also be light in proportion to their multitude And so when they are few they are heavy likewise when the atoms are light the air is rarified and thin and when they are heavy the air is thick And so upon the whole matter 't is evident that we cannot make such a precise and exact judgement of the variety of circumstances as to be able to determine when there is absolutely more cause of weight and when less And as we find not weight enough in either side of these opposite circumstances to turn the scales in our discourse so likewise we find the same indifference in experience it self for the weights we use do weigh equally in mysty weather and in clear and yet in rigor of discourse we cannot doubt but that in truth they do not gravitate or weigh so much though the difference be imperceptible to sense when the air is thick and foggy as when its pure and rarified Which thickness of the Medium when it arrives to a very
violently upon it as in the first measure when the string parting from it did beat it forwards for till then the velocity encreases in the arrow as it does in the string that carries it along which proceeds from rest at the fingers loose from it to its highest degree of velocity which is when it arrives to the utmost extent of its jerk where it quits the arrow And therfore the air now doth not so swiftly nor so much of it rebound back from before and clap it self behind the arrow to fill the space that else would be left void by the arrows moving forward and consequently the blow it gives in the third measure to drive the arrow on cannot be so great as the blow was immediately after the strings parting from it which was in the second measure of time and therefore the arrow must needs move slower in the third measure than it did in the second as formerly it moved slower in the second which was the airs first stroke than it did in the first when the string drove it forwards And thus successively in every moment of time as the causes grow weaker weaker by the encrease of resistance in the air before and by the decrease of force in the subsequent air so the motion must be slower and slower till it come to pure cessation As for Galileu's second argument that the air has little power over heavy things and therfore he will not allow it to be the cause of continuing forced motions in dense bodies I wish he could as well have made experience what velocity of motion a mans breath might produce in an heavy bullet lying upon an even hard and slippery plain for a table would be too short as he did how admirable great a one it produced in pendants hanging in the air and I doubt not but he would have granted it as powerful in causing horizontal motions as he found it in the undulations of his pendants Which nevertheless sufficiently convince how great a power air has over heay bodies As likewise the experience of wind-guns assures us that air duly applyed is able to give greater motion to heavy bodies than to light ones For how can a straw or feather be imagin'd possibly to fly with half the violence as a bullet of lead doth out of one of those Engines And when a man sucks a bullet upwards in a perfectly bored barrel of a Gun which the bullet fits exactly as we have mention'd before with what a violence doth it follow the breath and ascend to the mouth of the barrel I remember to have seen a man that was uncautious and sucked strongly that had his foreteeth beaten out by the blow of the bullet ascending This experiment if well look'd into may peradventure make good a great part of this Doctrine we now deliver For the air pressing in behind the bullet at the touch-hole gives it its impulse upwards to which the density of the bullet being added you have the cause of its swiftness and violence for a bullet of wood or cork would not ascend so fast and so strongly and the sucking away of the air before it takes away that resistance which otherwise it would encounter with by the air lying in its way and its following the breath with so great ease shews as we touch'd before that of it self 't is indifferent to any motion when nothing presses upon it to determine it a certain way Now to Galileo's last argument that an arrow should fly faster broad-ways than long-ways if the air were cause of its motion there needs no more to be said but that the resistance of the air before hinders it as much as the impulse of the air behind helps it on So that nothing is gain'd in that regard but much is lost in respect of the figure which makes the arrow unapt to cut the air so well when it flyes broad-ways as when 't is shot long-ways and therfore the air being weakly cut so much of it cannot clap in behind the arrow and drive it on against the resistance before which is much greater Thus far with due respect and with acknowledging remembrance of the many admirable mysteries of nature which that great man hath taught the world we have taken liberty to dipute against him because this difficulty seems to have driven him against his Genius to believe that in such motions there must be allow'd a quality imprinted into the moved body to cause them which our whole scope both in this and all other occasions where like qualities are urged is to prove superfluous and ill grounded in nature and to be but meer terms to confound and leave in the dark whoever is forced to fly to them CHAP. XIII Of three sorts of violent motion Reflection Undulation and Refraction THe motion we have last spoken of because 't is ordinarily either in part or wholy contrary to gravity which is accounted the natural motion of most bodies uses to be call'd violent or forced And thus you have deliver'd you the natures and causes both of Natural and of Forced Motion yet it remains that we advertise you of some particular kinds of this forced motion which seem to be different from it but indeed are not As first the motion of Reflection which if we but consider how forced motion is made we shall find it is nothing else but a forced motion whose line whereon 't is made is as it were snapp'd in two by the encounter of a hard body For even as we see in a spout of water strongly shot against a wall the water following drives the precedent parts first to the wall and afterwards coming themselves to the wall forces them again another way from the wall so the latter parts of the torrent of air which is caused by the force that occasion'd the forced motion drives the former parts first upon the resistant body and afterwards again from it But this is more eminent in light than in any other body because light doth less rissent gravity and so observes the pure course of the stroke better than any other body from which others for the most part decline some way by reason of their weight Now the particular law of reflection is that the line incident the line of reflection must make equal angles with that line of the resistent superficies wch is in the same superficies with themselvs The demonstration wherof that great wit Renatus des Cartes hath excellently set down in his book of Dioptricks by the example of a ball strucken by a Racket against the earth or any resisting body the substance wherof is as follows The motion which we call Undulation needs no further explication for 't is manifest that since a Pendent when 't is removed from its perpendicular will restore it self therto by the natural force of gravity and that in so doing it gains a velocity and therefore cannot cease on a suddain it must needs be
same point of incidence in a shorter line and a greater angle than another does In both these wayes 't is apparent that a body composed of greater parts and greater pores exceeds bodies of the opposite kind for by reason that in the first kind more light may beat against one part a body in which that happens will wake an appearance from a further part of its superficies wheras in a body of the other sort the light that beats against one of the little parts of it will be so little as 't will presently vanish Again because in the first the part at the incidence is greater the surface from which the reflection is made inwards has more of a plain and straight superficies and consequently reflects at a greater angle than that whose superficies hath more of inclining But we must not pass from this question without looking a little into the nature of those bodies in which refraction is made for if they as well as the immediate causes of refraction likewise favour us it will not a little advance the certainty of our determination To this purpose we may call to mind how experience shews us that great refractions are made in smoke and mists and glasses and thick-bodied waters and Monsir des Cartes adds certain Oyls and Spirits or strong Waters Now most of these we see are composed of little consistent bodies swimming in another liquid body As is plain in smoke and mists for the little bubbles which rise in the water before they get out of it and that are smoke when they get into the air assure us that smoke is nothing else but a company of little round bodies swimming in the air and the round consistence of water upon herbs leavs twigs in a rind or dew gives us also to understand that a Mist is likewise a company of little round bodies that sometimes stand sometimes float in the air as the wind drives them Our very eyes bear witness to us that the thicker sort of waters are full of little bodies which is the cause of their not being clear As for Glass the blowing of it convinces that the little darts of fire which pierce it every way do naturally in the melting of it convert it into little round hollow bodies which in their cooling must settle into parts of the like figure Then for Chrystal and other transparent stones which are found in cold places it cannot be otherwise but that the nature of cold piercing into the main body and contracting every little part in it self this contraction must needs leave vacant pores between part and part And that such transparent stones as are made by heat have the like effect and property may be judg'd out of what we see in Bricks and Tiles which are left full of holes by the operation of the fire And I have seen in bones that have lain a long time in the Sun a multitude of sensible little pores close to one another as if they had been formerly stack all over with subtile sharp needles as close as they could be thrust in by one another The Chymical Oyles and Spirits which Monsir des Cartes speaks of are likely to be of the same composition since such use to be extracted by violent fires for a violent fire is made by the conjunction of many rayes together and that must needs cause great pores in the body it works on and the sticking nature of these spirits is capable of conserving them Out of all these observations it follows that the bodies in which greatest refractions happen are compounded as we have said of great parts and great pores and therfore by only taking light to be such a body as we have described it where we treated of its nature 't is evident the effect we have exprest must necessarily follow by way of reflection and refraction is nothing else but a certain kind of reflection Which last assertion is likewise convinced out of this that the same effects proceed from reflection as from refraction for by reflection a thing may be seen greater than it is in a different place from the true one where it is colours may be made by reflection as also gloating light and fire likewise and peradventure all other effects which are caused by refraction may as well as these be perform'd by reflection And therfore 't is evident they must be of the same nature since children are the resemblances of their parents CHAP. XIV Of the composition qualities and generation of mixed bodies HAving now declar'd the vertues by which Fire and Earth work upon one another and upon the rest of the Elements which is by Light and the motions we have discours'd of Our task shall be in this Chapter first to observe what will result out of such action of theirs and next to search into the ways and manner of compassing and performing it Which latter we shall the more easily attain to when we first know the end that their operation levels at In this pursuit we shall find that the effect of the Elements combinations by means of the motions that happen among them is a long pedegree of compounded qualities and bodies wherein the first combinations like marriages are the breeders of the next more-composed substances and they again are the parents of others in greater variety and so are multiplied without end for the further this work proceeds the more subjects it makes for new business of the like kind To descend in particular to all these is impossible And to look further then the general heads of them were superfluous and troublesome in this discourse wherin I aim only at shewing what sorts of things in common may be done by Bodies that if hereafter we meet with things of another nature and strain we may be sure they are not the off-spring of bodies and quantity which is the main scope of what I have design'd here And to do this with confidence certainty requires of necessity this leisurely and orderly proceeding we have hitherto used and shall continue to the end For walking thus softly we have always one foot upon the ground so as the other may be sure of firm footing before it settle Wheras they that for more hast will leap over rugged passages and broken ground when both their feet are in the air cannot help themselvs but must light as chance throws them To this purpose then we may consider that the qualities of bodies in common are of three sorts For they are belonging either to the Constitution of a compounded body or else to the Operation of it and the Operation of a body is of two kinds one upon Other Bodies the other upon Sense The last of these three sorts of qualities shall be handled in a peculiar Chapter by themselvs Those of the second sort wherby they work upon Other bodies have been partly declar'd in the former chapters and will be further discours'd of in the rest of this first
soft and liquid bodies easily joyn and incorporate into one continued body but hard and dry bodies so difficultly as by experience we find to be true Water with water or wine either with other wine or with water so unites that 't is very hard to part them but sand or stones cannot be made to stick together without very great force and industry The reasons whereof must necessarily depend of what we have said above To wit that two bodies cannot touch one another without becoming one and that if two bodies of one degree of density do touch they must stick together according to the force of that degree of density Out of which two is manifestly infer'd that if two hard things should come to touch they must needs be more difficultly separated then two liquid things And consequently they cannot come to touch without as much difficulty as that wherby they are made one But to deduce this more particularly let us consider that all the little surfaces by which one hard body may be conceiv'd to touch another as for example when a stone lies upon a stone must of necessity be either plain or concave or convex Now if a plain superficies should be supposed to touch another plain one coming perpendicularly to it it must of necessity be granted to touch it as soon in the middle as on the sides Wherfore if there were any air as of necessity there must be betwixt the two surfaces before they touch'd it will follow that the air which was in the midle must have fled quite out from between the two surfaces as soon as any part of the surfaces touch that is as soon as the air which was between the utmost edges of the surfaces did fly out and by consequence it must have moved in an instant But if a plain surface be said to touch a convex surface it touches it only by a line as Mathematicians demonstrate or a point But to touch by a line or a point is in truth not to touch by the form or motion of Quantity which requires divisibility in all that belongs to it and by consequence among bodies it is not-to-touch and so one such surface doth not touch the other Now for a plain surface to touch a concave every man sees is impossible Likewise for two convex surfaces to touch one another they must be allow'd to touch either in a line or in a point which we have shew'd not to be a physical touching And if a convex surface should be said to touch a concave they must touch all at once as we said of plain surfaces and therfore the same impossibility will arise therein So that 't is evident no two surfaces moving perpendicularly towards one another can come to touch one another if neither of them yields and changes its hew Now then if it be supposed they come slidingly one over another in the same line wherby first the very tips of the edges come to touch one another and still as you shove the uppermost on forwards and it slides over more of the nether surface it gains to touch more of it I say that neither in this case do they touch immediately one another For as soon as the two first parts should meet if they did touch and there were no air between them they must presently become one quantity or body as we have declared and must stick firmly together according to their degree of density and consequenly could not be moved on without still breaking asunder at every impulse as much of the massie body as were already made one by their touching And if you should say they did not become one and yet allow them to touch immediately one another without having any air or fluid body between them then if you suppose them to move onwards upon these terms they would be changed locally without any intrinsecal change which in the book De Mundo as we have formerly alledg'd is demonstrated impossible There remains only a third way for two hard surfaces to come together which is that first they should rest sloping one upon another and make an angle where they meet as two lines that cut one another doe in the point of their intersection and so contain as it were a wedge of air between them which wedge they should lessen by little and little through their moving towards one another at their most distant edges whiles the touching edges are like immoveable centers that the others turn upon till at length they shut out all the air and close together like the two legs of a compass But neither is it possible that this way they should touch For after their first touch by one line which neither is in effect a touching as we have shewed no other parts of them can touch though still they approach nearer and nearer till their whole surfaces entirely touch at once and therefore the air must in this case leap out in an instant a greater space then if the surfaces came perpendicularly to one another for here it must flie from one extremity to the other whereas in the former case it was to go but from the middle to each side And thus 't is evident that no two bodies can arrive to touch one another unless one of them at the least have a superficies plyable to the superficies of the other that is unless one of them be soft which is to be liquid in some degree Seeing then that by touching bodies become one and liquidity is the cause and means whereby bodies arrive to touch we may boldly conclude that two liquid bodies most easily and readily become one and next to two such a liquid and a hard body are soonest united but two hard ones most difficultly To proceed then with our reflections upon the composition of Bodies and upon what results out of the joyning and mixture of their first differences Rarity and Density we see how if a liquid substance happens to touch a dry body it sticks easily thereto Then consider there may be so small a quantity of such a liquid body as it may be almost impossible for any natural agent to divide it further into less parts and suppose that such a liquid part is between two dry parts of a dense body and sticking to them both becomes like a glew to hold them together will it not follow out of what we have said that these two dense parts will be as hard to be severed from one another as the small liquid part by which they stick together is to be divided So that when the viscuous ligaments which in a body hold together the dense parts are so small and subtile as no force we can apply can divide them the adhesion of the parts must needs grow then inseparable And therefore we use to moisten dry bodies to make them more easily be divided whereas those that are over-moist are of themselves ready to fall in pieces And thus you see how in general
bodies are framed Out of which discourse we may ballance the degrees of solidity in bodies For all bodies being composed of humide and dry parts we may conceive either kind of those parts to be bigger or lesser or to be more rare or more dense Now if the dry parts of any body be extreme little and dense and the moist parts that joyn the dry ones together be very great and rare then that body will be very easie to be dissolv'd But if the moist parts which glew together such extreme little and dense dry parts be either lesser in bulk or not so rare then the body composed of them will be in a stronger degree of consistence And if the moist parts which serve for this effect be in an excess of littleness and withal dense then the body they compose will be in the highest degree of consistence that nature can frame On the other side if you glew together great dry parts which are moderately dense great by the admixtion of humid parts that are of the least size in bulk and dense withal then the consistence will decrease from its height by how much the parts are greater and the density less But if to dry parts of the greatest size and in the greatest remisness of density you add humid parts both very great and very rare then the composed body will prove the most easily dissolveable of all that nature affords After this casting our eyes a little further towards the composition of particular bodies we shall find still greater mixtures the further we go for as the first and simplest compounded bodies are made of the four Elements so others are made of these and again a third sort of them and so on-wards according as by motion the parts of every one are broken in sunder and mingled with others Those of the first order must be of various tempers according to the proportions of the Elements whereof they are immediatly made As for example such a proportion of Fire to the other three Elements will make one kind of simple body and another proportion will make another kind and so throughout by various combinations and proportions among all the Elements In the effecting of which work it will not be amiss to look a little upon nature and observe how she mingles and tempers different bodies one with another wherby she begets that great variety of creatures we see in the World But because the degrees of composition are infinite according to the encrease of number we will contain our selves within the common notions of excess in the four primary components for if we should descend once to specifie any determinate proportions we should endanger losing our selvs in a wood of particular natures which belong not to us at present to examin Then taking the four Elements as materials to work upon let us first consider how they may be varied that differing compositions may result out of their mixtures I conceive that all the ways of varying the Elements in this regard may be reduced to the several sizes of Bigness of the Parts of each Element that enter into the composition of any body and to the Number of those Parts for certainly no other can be imagin'd unless it were variety of Figure But that cannot be admited to belong in any constant manner to those least particulars wherof bodies are framed as if determinate figures were in every degree of quantity due to the natures of Elements and therfore the Elements would conserve themselves in those figures as well in their least atoms as massie bulk For seeing how these little parts are shuffled together without any order and that all liquids easily joyn and take the figures which the dense ones give them and that they again justling one another crush themselves into new shapes to which their mixture with the liquid ones makes them yield the more easily t is impossible the elements should have any other natural figure in these their least parts then such as chance gives them But that one part must be bigger then another is evident for the nature of rarity and density gives it the first of them causing divisibility into little parts and the latter hindring it Having then settled in what manner the Elements may be varied in the composition of bodies let us now begin our mixture In which our ground to work upon must be Earth and Water For only these two are the Basis of permanent bodies that suffer our senses to take hold of them and submit themselvs to trial Wheras if we should make the predominant Element to be Air or Fire and bring in the other two solid ones under their jurisdiction only to make up the mixture the compound resulting out of them would be either in continual consumption as ordinary fire is or else through too much subtlety imperceptible to our eyes or touch therfore not a fit subject for us to discourse of especially since the other two Elements afford us enough to speculate on Peradventure our Smel might take some cognisance of a body so composed or the effect of it taken in by respiration might in time shew it self upon our health but it concerns not us now to look so far our design requires more maniable substances Of these then let Water be the first and with it we will mingle the other three elements in excess over one another by turns but stil all of them oversway'd by a predominant quantity of water and then let us see what kind of bodies will result out of such proportions First if earth prevail above fire and air and arrive next in proportion to the water a body of such a composition must needs prove hardly liquid and not easie to let its parts run a sunder by reason of the great proportion of so dense a body as earth that holds it together Yet some inclination it will have to fluidness by reason the water is predominant over all which also will make it be easily divisible and give every little resistance to any hard thing that shall be apply'd to make way through it In a word this mixture makes the constitution of Mud Dirt Honey Butter and such like things where the main parts are great ones And such are the parts of earth and water in themselvs Let the next proportion of excess in a watry compound be of air which when it prevails incorporates it self chiefly with earth for the other Elements would not so well retain it Now because its parts are subtile by reason of the rarity it hath and sticking because of its humidity it drives the earth and water likewise into lesser parts The result of such a mixture is that the parts of a body compounded by it are close catching flowing slowly glibb and generally it will burn and be easily converted into flame Of this kind are those we call Oyly or unctuous bodies whose great parts are easily separated that is easily divisible
if afterwards by any accident there comes a great compression they force them to lose their natural rarity and to become some other Element Thus it fares with fire both in acting and suffering And the same course we have in both these regards expressed of it passes likewise in the rest of the Elements to the proportion of their contrarieties Hence it follows that when fire meets with humidity in any body it divides and subtilises it and disperses it gently and in a kind of equal manner through the whole body it is in if the operation of it be a natural and a gentle one and so drives it into other parts which at the same time it prepares to receive it by subtilising likewise those parts And thus moderate fire makes humour in very smal parts to incorporate it self in an even or uninform manner with the dry parts it meets with which being done whether the heat afterwards continues or the cold succeeds in lieu of it the effect must of necessity be that the body thus compos'd be bound up and fastn'd more or less according to the proportion of the Matter 't is made of of the Agents that work upon it and of the Time they employ about it This is every day seen in the ripening of fruits and in other frequent works as well of art as of nature and is so obvious and sensible to any reasonable observation that t is needless to enlarge my self much upon this subject Only it will not be amiss for examples sake to consider the progress of it in the composing or augmenting of metals or earths of divers sorts First heat as we have said draws humour out of all the bodies it works on then if the extracted humour be in quantity and the steams of it happen to come together in some hollow place fit to assemble them into greater parts they are condens'd and fall down in a liquid and running body These streams being corporified the body resulting out of them makes it self in the earth a channel to run in and if there be any loose parts in the channel they mingle themselvs with the running liquor and though there be none such yet in time liquor it self loosens the channel all about and imbibes into its own substance the parts it raises And thus all of them compacted together roll along till they tumble into some low place out of which they cannot so easily get to wander further When they are thus settled they the more easily receive into them and retain such heat as is every where to be met withal because it is diffused more or less through the earth This heat if it be sufficient digests it into a solid body the temper of cold likewise concurring in its measure to this effect And according to the variety of the substances wherof the first liquor was made and which it afterwards drew along with it the body that results out of them is diversifyed In confirmation of all which they that deal in Mines tell us they use to find metalls oftentimes mingled with stones as also coagulated juyces with both and earths of divers natures with all three and they with it and one with another among themselvs And that sometimes they find the mines not yet consolidated and digested throughly into metal when by their experience knowing after how many years they will be ripe they shut them up again till then Now if the hollow place wherin the body stay'd which at first was liquid and rolling be not at once filled by it but it takes up only part of it and the same liquor continues afterwards to flow thither then this body is augmented and groweth bigger and bigger And though the liquors should come at several times yet they become not therfore two several bodies but both grow into one body for the wet parts of the adventititious liquor mollifie the sides of the body already baked and both of them being of a like temper and cognation they easily stick and grow together Out of this discourse it follows evidently that in all sorts of compounded bodies whatever there must of necessity be actually comprised sundry parts of divers natures for otherwise they would be but so many pure degrees of rarity and density that is they would be but so many pure Elements and each of them have but one determinate virtue or operation CHAP. XV. Of the dissolution of mixed bodies THus much for composition of Bodies Their dissolution is made three wayes either by fire or by water or by some outward violence We will begin with examining how this last is done To which end we may consider that the unity of any body consisting in the connexion of its parts 't is evident the force of motion if it be exercised upon them must of necessity separate them as we see inbreaking cutting filing drawing asunder and the like All these motions because they are done by gross bodies require great parts to work upon are easily discern'd how they work so that it is not difficult to find the reason why some hard bodies break easily and others with much ado The first of which are called brittle the others tough For if you mark it all breaking requires that bending should precede which on the one side compresses the parts of the bended body and condenses them into a lesser room then they possess'd before and on the other side stretches them out and makes them take up more place This requires some fluid or moveable substance to be within the body else it could not be done for without such help the parts could not remove Therfore such hard bodies as have most fluid parts in them are most flexible that is are toughest and those whcih have fewest though they become therby hardest to have impression made upon them yet if the force be able to do it they rather yield to break then to bend and thence are called brittle Out of this we may infer that some bodies may be so suddenly bent as that therby they break afunder wheras if they were leisurely and gently dealt withal they would take what play one desires And likewise that there is no body be it never so brittle and hard but it will bend a little and indeed more then one would expect if it be wrought upon with time dexterity for there is none but contains in it some liquid parts more or less even glass and brick Upon which occasion I remember how once in a great storm of wind I saw the high slender brick Chimneys of the Kings house at S. James's one winter when the Court lay there bend from the wind like boughs and shake exceedingly and totter And at other times I have seen some very high and pointy Spire Steeples do the like And I have been assured the like of the whole pile of a high castle standing in a gullet in the course of the winde namely the castle of Wardour who have often seen it
shake notably in a fierce wind The reason of all which may be deduced out of what we have said above For since the bending of a body makes the spirits or humours within it to sally forth 't is clear if the violence which forces it be not so sudden nor the motion it receives so quick but that the moisture may oose gently out the body will bend stil more and more as their absence gives it leave But if the motion wrought in it be too quick then the spirits not having time allow'd them to go leisurely and gently out force their prison and break out with a violence and so the body is snap'd in two Here peradventure some remembring what we have said in another place namly that it is the shortness and littleness of the humid parts in a body which makes it stick together and that this shortness may be in so high a degree as nothing can come between the parts they glew together to divide them may ask how a very dense body of such a strain can be broken or divided But the difficulty is not great for since the humid parts in whatever degree of shortness they be must necessarily have stil some latitude it cannot be doubted but there may be some force assign'd greater then their resistance can be All the question is how to apply it to work its effect upon so close a compacted body in which peradventure the continuity of the humid parts that bind the others together may be so small as no other body whatever no not fire can go between them so as to separate part from part At the worst it cannot be doubted but that the force may be so apply'd at the outside of that body as to make the parts of it press and fight one against another and at length by multiplication of the force constrain it to yield and suffer division And this I conceive to be the condition of gold and some precious stones in which the elements are united by such little parts as nothing but a civil war within themselvs stir'd up by some subtile outward enemy wherby they are made to tear their own bowels could bring to passe their destruction But this way of dissolving such bodies more properly belongs to the next way of working upon them by fire yet the same is done when some exteriour violence pressing upon those parts it touches makes them cut a way betwixt their next neighbours and so continuing the force divide the whole body As when the chisel or even the hammer with beating breaks gold asunder for it is neither the chisel nor the hammer that doth that effect immediately but they make those parts they touch cut the others that they are forced upon As I remember hap'ned to a Gentleman that stood by me in a Sea-fight I was in with a coat of mail upon his body when a bullet coming against a bony part in him made a great wound and shatter'd all the bones near where it struck and yet the coat of mail was whole it seems the little links of the mail yielding to the bullets force made their way into the flesh and to the bone But now 't is time to come to the other two instuments of separation of bodies Fire and water and to examine how they dissolve compounds Of these two the way of working of fire is the easiest and most apparant to be discerned We may readily observe how it proceeds if we but set a piece of wood on fire in which it makes little holes as if with bodkins it pierced it So that the manner of its operation in common being plain we need but reflect a little upon the several particular degrees of it Some bodies it seems not to touch as clothes made of Asbestus which are only purifyed by it Others it melts but consumes not as gold Others it turns into powder suddenly dissolving their body as lead and such metalls as are calcined by pure fire Others again it separates into a greater number of differing parts as into Spirits Waters Oyls Salt Earth and Glass of which rank are all vegetables And lastly others it converts into pure fire as strong Waters or Aquavites called Aquae ardentes and some pure Oyls for the smoak that is made by their setting on fire and peradventure their salt is so little as is scarce discernable These are in sum the divisions which fire makes upon bodies according to their nature and its due application to them for by the help and mediation of other things it may peradventure work other effects Now to examine a little in particular how the same fire in differing subjects produces such different effects Limus ut hic durescit haec ut câ—ra liquescit Uno eodemque igni We will consider the nature of every one of the subjects apart by it self First for the Asbestus 't is clear it is of a very dry substance so that to look upon it when it is broken into very little pieces they seem to be little bundles of short hairs the liquidity within being so little as it affords the parts neither length nor breadth and therefore fire meets with little there that it can dilate But what it cannot dilate it cannot separate nor carry away any thing of it but what is accidentally adherent to the outsides of it And so it seems only to pass through the pores and cleanse the little thrids but brings no detriment at all to the substance of it In this I speak only of an ordinary fire for I doubt not but such a one it might be as would perfectly calcine it The next body we spake of is Gold This abounds so much in liquidity that it stickes to the fire if duly apply'd but its humidity is so well united to its earthy parts and so perfectly incorporated with them as it cannot carry away one without both but both are too heavy a weight for the little agile parts of fire to remove Thus it is able to make Gold swell as we see in melting it in which the Gold receives the fire into its bowels and retains it a long time with it but at its departure it permits the fire to carry nothing away upon its wings as is apparant by the Golds no whit decay of weight after never so long fusion And therefore to have fire make any separation in Gold requires the assistance of some other moist body that on the one side may stick closely to the Gold when the fire drives it into it and on the othe rside may be capable of dilatation by the action of the fire upon it As in some sort we see in Strong Waters made of Salts being a proper subject for the fire to dilate which by the assistance of fire mingling themselves closely with little parts of the Gold pull them away from their whole substance and force them to bear them company in their journey upwards in which multitudes of little parts of fire
concur to press on and hasten them and so the weight of gold being at length overcome by these two powerful Agents whereof one supplies what the other wants the whole substance of the metal is in little atomes diffused through the whole body of the water But this is not truly a dissolution or separation of the substantial parts of Gold one from another 't is only a corrosion which brings it into a subtile powder when the water salts are separated from it much like what filing though far smaller or grinding of leaf gold upon a porphyre stone may reduce it into for neither the parts of the water nor of the fire that make themselvs a way into the body of the gold are small and subtile enough to get between the parts that compose the essence of it and therefore all they can attain to is to divide it only in its quantity or bulk not in the composition of its nature Yet I intend not to deny but this is possible to be arrived to either by pure fire duly apply'd or by some other assistance as peradventure by some kind of Mercury which being of a nearer cognation to Metals then any other Liquor is may happily have a more powerful ingression into gold then any other body whatever and being withal very subject to rarefaction may after it is inter'd so perfectly penetrate the gold as it may separate every least part of it and so reduce it into an absolute calx But in this place I explicate no more then what ordinarily passes leaving the mysteries of this Art to those who profess it To go on then with what we have in hand Lead hath abundance of water overmingled with its earth as appears by its easie yielding to be bent any way and by its quiet standing bent in the same position that the force which bowed it leaves it in And therefore the liquid parts of Lead are easily separated from its dry and earthy ones and when it is melted the very shaking of it causes the gross parts to descend and many liquid ones to flie away with the fire so that suddenly it is thus converted into powder But this powder is gross in respect of other metals unless this operation be often reiterated or the fire more powerfully apply'd then what is just enough to bring the body of the Lead into powder The next consideration of bodies that fire works upon is of such as it divides into Spirits Salts Oyls Waters or Phlegms and Earth Now these are not pure and simple parts of the dissolv'd body but new compounded bodies made of the first by the operation of heat As Smoak is not pure water but water and fire together and therefore becomes not water but by cooling that is by the fire flying away from it So likewise those Spirits Salts Oyls and the rest are but degrees of things which fire makes of diverse parts of the dissolved body by separating them one from another and incorporating it self with them And so they are all of them compounded of the four Element and are further resolvable into them Yet I intend not to say that there are not originally in the body before its dissolution some loose parts which have the properties of these bodies that are made by the fire in the dissolving of it For seeing that nature works by the like instruments as art uses she must need in her excesses and defects produce like bodies to what art doth in dissolution which operation of art is but a kind of excess in the progress of nature But my meaning is that in such dissolution there are more of these parts made by the working of fire then were in the body before Now because this is the natural and most ordinary dissolution of things let us see in particular how it is done Suppose then that fire were in a convenient manner apply'd to a body that hath all sorts of parts in it and our own discourse will tell us the first effect it works will be that as the subtile parts of fire divide and pass through that body they will adhere to the most subtile parts in it which being most agile and least bound and incorporated to the bowels of the body and lying as 't were loosly scatter'd in it the fire will carry them away with it These will be the first that are separated from the main body which being retain'd in a fit receiver will by the coldness of the circumdant air grow outwardly cool themselves and become first a dew upon the sides of the glass and then still as they grow cooler condense more and more till at length they fall down congeal'd into a palpable liquor which is composed as you see of the hotest parts of the body mingled with the fire that carried them out and therfore this liquor is very inflamable and easily turn'd into actual fire as you see all Spirits and aquae ardentes of vegetables are The hot and loose parts being extracted and the fire continuing and encreasing those that will follow next are such as though they be not of themselvs loose yet are easiest to be made so and are therfore most separable These must be humide and those little dry parts which are incorporated with the overflowing humide ones in them for no parts that we can arrive to are of one pure simple nature but all mixed and composed of the four Elements in some proportion must be held together with such gross glew as the fire may easily penetrate and separate them And then the humide parts divided into little atoms stick to the lesser ones of the fire which by their multitude of number and velocity of motion supplying what they want of them in bulk carry them away with them And thus these Phlegmatick parts flie up with the fire and are afterwards congeal'd into an insipide water which if it have any savour 't is because the first ardent spirits are not totally separated from it but some few of them remain in it and give some little life to the whole body of that otherwise flat liquor Now those parts which the fire separates next from the remaining body after the fiery and watry ones are carryed away must be such as it can work upon and therfore must abound in humidity But since they stir not till the watry ones are gone 't is evident they are composed of many dry parts strongly incorporated and very subtilly mixed with the moist ones and that both of them are exceeding small and so closely and finely knit together that the fire hath much ado to get between and cut the thrids that tie them together and therfore they require a very great force of fire to carry them up Now the composition of these shewes them to be Aerial and together with the fire that is mingled with them they congeal into that consistence which we call Oyl Lastly it cannot be otherwise but that the fire in all this while of
where they are little holes or pores in the places they are compressed driven from which pores they filled up when they were dilated at their own natural liberty But being thus forcibly shrunk up into less room afterwards they squees again out of their croud all such very loose and subtile parts residing till then with them as can find their way out from among them And these subtile parts that thus are deliver'd from the colds compressions get first into the pores that we have shew'd were made by this compression But they cannot long stay there for the atoms of advenient cold that obsess the compressed body do likewise with all their force throng ito those pores and soon drive out the subtile guests they find there because they are more in number bigger in bulk and more violent in their course then they Who therfore must yield to them the little channels and capacities they formerly took up Out of which they are thrust with such an impetuositie that they spin from them with a vehemence as Quick silver doth through leather when to purifie it or bring an Amalgame to a due consistence it is strained through the sides of it Now these showrs or streams of atomes issuing from the compressed body are on all sides round about it at exceeding little distances because the pores out of which they are driven are so likewise And consequently there they remain round about besieging it as though they would return to their original homes as soon as the usurping strangers that were too powerful for them will give them leave And according to the multitude of them and to the force with which they are driven out the compass they take up round about the compressed body is greater or lesser Which besieging atomes are not so soon carried away by any exterior and accidental causes but they are supplied by new emanations succeeding them out of the said compressed body Now this which we have declared by the example of cold compressing a particular body happens in all bodies wherever they be in the world For this being the unavoidable effect of heat and of cold wherever they reside which are the active qualities by whose means not only fire and water and the other two Elements but all other mixed bodies composed of the Elements have their activity and they being in all bodies whatever as we have proved above it follows evidently that there is not a body in the world but has about it self an orbe of emanations of the same nature which that body is of Within the compass of which orbe when any other body comes that receives an immutation by the little atomes whereof that orbe is composed the advenient body seems to be affected and as it were replenished with the qualities of the body from whence they issue Which is then said to work upon the body that imbibes the emanations that flow from it And because this orbe regularly speaking is in the form of a Sphere the passive body is said to be within the Sphere of the others activity Secondly when Philosophers pronounce that No corporeal nature can operari in distans that is that no body can work upon another remote from it without working first upon the body that lies between them which must continue and place up the operation from the agent to the patient The reason and truth of this maxime is in our Philosophy evident For we having shew'd that action among bodies is performed for the most part by the emission of little parts out of one body into another as also that such little parts cannot stream from the body that is their fountain and settle upon a remote body without passing through the interjacent bodies which must furnish them as it were with channels and pipes to convey them whither they are to go it follows manifestly that the active emissaries of the working body can never reach their distant mark unless they be successively ferried over the medium that lies between them in which they must needs leave impressions of their having been there and so work upon it in their passe and leave in it their qualities and complexions as a payment for their wastage over But peradventure some may contend that these invisible Serjeants and workmen are too feeble and impotent to perform those visible great effects we daily see As when fire at the length burns a board that has been a great while opposed to it though it touch not the body of the fire or when a loadstone draws to it a great weight of Iron that is distant from it To whom we shall reply that if he will not grant these subtile emanations from the agent body to be the immediate workers of these effects he must allot that efficacy to the whole corpulency of all the Agent working in bulk for besides the whole the parts there is no third thing to be consider'd in bodies since they are constituted by quantity But the whole cannot work otherwise then by local motion which in this case it cannot do because by the supposition it is determin'd to keep its distance from the passive body and not to move towards it Therfore this is impossible whereas the other can appear but difficult at the worst and therefore must be admitted when no better and more intelligible solution can be found But withal we must note that it is not our intention to say but it may in some circumstances happen that some particular action or effect may be wrought in a remote part or body which shall not be the same in the intermediate body that lies between the agent and the patient and conveyes the agents working atomes to the others body As for example when tinder or Naphtha is by fire made to burn at a yard distance from it when the interjacent air is but warm'd by that fire Or when the Sun by means of a burning-glass or some other reflection sets some bodies on fire and yet only enlightens the glass and the air that are in the way The reason of which is manifest to be the divers dispositions of the different subjects in regard of the Agent and therfore 't is no wonder that divers effects should be produced according to those divers dispositions A third position among Philosophers is that All bodies which work upon others at the same time suffer from those they work upon and contrariwise all bodies which suffer from others at the same time work back again upon them For the better understanding wherof let us consider that all action among bodies is either purely local motion or else local motion with certain particularities which give it a particular name As when we express the local motion of little atomes of fire or of earth or water upon and into other bodies by the words of heating or cooling and so of the like Now if the action be pure local moâ—on and consequently the effect produced by that action be meerly
away all the palpable moisture And so when wet cloathes are hang'd either in the Sun or at the fire we see a smoake about the cloathes and heat within them which being all drawn out from them they become dry And this deserves a particular note that although they should be not quite dry when you take them from the fire yet by that time they are cool they will be dry for the fire that is in them when removed from the main stock of fire flying away carries with it the moisture that was incorporated with it And therfore whiles they were hot that is whiles the fire was in them they must also be moist because the fire and the moisture were grown to be one body and could not become through dry with that measure of fire for more would have dry'd them even whiles they were hot until they were also grown through cold And in like manner Syrups Hydromels Gellies and the like grow much thicker after they are taken off from the fire than they were upon the fire and much of their humidity flies away with the fire in their cooling wherby they lessen much of their quantity even after the outward fire hath ceased from working upon them Now if the moist parts that remain after the drying be by the heat well incorporated in the dry parts and so occasion the dry parts to stick close together then that body is condensed and will to the proportion of it be heavier in a less bulk as we see that Metals are heavier than Stones Although this effect be in those examples wrought by heat yet generally speaking it is more proper to cold which is the Second Way of drying a moist body As when in Greenland the extreme cold freeses the Whalefishes Beer into Ice so that the stewards divide it with Axes and Wedges and deliver their portions of drinks to their ships company and their Shallops gings in their bare hands but in the innermost part of the Butt they find some quantity of very strong liquor not inferiour to moderate spirit of Wine At first before custome had made it familiar to them they wonder'd that every time they drew at the tap when first it came from their ships to the shore for the heat of the hold would not let it freese no liquor would come unless they new tap'd it with a longer gimlet but they thought that pains well recompen'd by finding it in the tast to grow stronger and stronger till at last their longest gimlets would bring nothing out and yet the vessel not a quarter drawn off which obliged them then to stave the Cask that so they might make use of the substance that remain'd The reason of this is evident That cold seeking to condense the beer by mingling its dry and cold parts with it those that would indure this mixture were imbibed and shrunk up by them But the other rare and hot parts that were squees'd out by the dense ones which enter'd to congeal the beer and were forced into the middle of the vessel which was the furthest part for them to retire to from their invironing enemies conserv'd themselvs in their liquid form in defiance of the assaulting cold whiles their fellows remaining by their departure more gross and earthy then they were before yielded to the conquerour they could not shift away from and so were dry'd and condens'd in ice which when the Marriners thaw'd they found like fair water without any spirits in it or comforting heat to the stomack This manner of condensation which we have described in the freezing of Beer is the way most practis'd by nature I mean for immediate condensation for condensation is secondarily wherever there is rarefaction which we have determin'd to be an effect of heat And the course of it is that a multitude of earthy and dry bodies being driven against any liquor easily divide it by means of their density their driness and their littleness all which in this case accompany one another and are by us determin'd to be powerful dividers and when they are gotten into it they partly suck into their own pores the wet and diffused parts of the liquid body and partly they make them when themselvs are full stick fast to their dry sides and become as a glew to hold themselves strongly together And thus they dry up the liquor and by the natural pressing of gravity contract it into a lesser room No otherwise then when we force much wind or water into a bottle and by pressing it more and more make it lye closser then of its own nature it would do Or rather as when ashes are mingled with water both those substances stick so close to one another that they take up less room theâ— they did each apart This is the method of Frosts and Snow and Ice both natural and artificial For in natural freezing ordinarily the North or Northeast Wind by its force brings and drives into our liquors such earthy bodies as it has gather'd from rocks cover'd with snow which being mix'd with the light vapours whereof the wind is made easily find way into the liquors and then they dry them into that consistence we call Ice Which in token of the wind it has in it swims upon the water and in the vessel where it is made rises higher then the water did wherof it is composed and ordinarily it breaks from the sides of the vessel so giving way to more wind to come in and freeze deeper and thicker But because Galileus In his Discourses Intorno alle cose che stanno in su l' accqua pag. 4. was of opinion that Ice was water rarified and not condens'd we must not pass over this verity without maintaining it against the opposition of so powerful an adversary His arguments are first that Ice takes up more place then the water did of which it was made which is against the nature of condensation Secondly that quantity for quantity Ice is lighter then water wheras things that are more dense are proportionally more heavie And lastly that Ice swims in water wheras we have aften taught that the more dense desends in the more rare Now to reply to these arguments we say first that We would gladly know how he did to measure the quantity of the Ice with the quantity of the Water of which it was made and then when he hath shew'd it and shew'd withall that Ice holds more place then water we must tell him that his experiment concludes nothing against our doctrine because there is an addition of other bodies mingled with the water to make Ice of it as we touch'd above and therefore that compound may well take up a greater place then the water alone did and yet be denser then it and the water also be denser then it was And that other bodies do come into the water and are mingled with it is evident out of the exceeding coldness of the aire or some very old wind one of
air or other cold bodies to thicken and condense as above we mentioned of Syrups and Jellies and so they are brought to stick firmly together In like manner we see that when two metals are heated till they be almost brought to running and then are pressed together by the hammer they become one continued body The like we see in glass the like in wax and in divers other things Onthe contrary side when a broken stone is to be pieced together the pieces of it must be wetted and the cement must be likewise moistned and then joyning them aptly and drying them they stick fast together Glew is moistned that it may by drying afterwards hold pieces of wood together And the Spectale-makers have a composition which must be both heated and moistned to joyn to handles of wood the glasses they are to grind And broken glasses are cemented with cheese and chalk or with garlick All these effects our sense evidently shews us arise out of condensation but to our reason it belongs to examine particularly by what steps thy are perform'd First then we know that heat subtilizes the little bodies which are in the pores of the heated body and partly also it opens the pores of the body it self if it be of a nature that permits it as it seems those bodies are which by heat are mollified or are liquofactable Again we know that moisture is more subtile to enter into small creeks then dry bodies are especially when it is pressed for then it will be divided into very little parts and will fill up every little chinck and nevertheless if it be of a gross and viscuous nature all the parts of it will stick together Out of these two properties we have that since every body has a kind of orb of its own exhalations or vapours round about it self as is before declared the vapours which are about one of the bodies will more strongly and solidly that is in more abundant and greater parts enter into the pores of the other body against which it is pressed when they are opened and dilated and thus they becoming common to both bodies by flowing from the one and streaming into the other and sticking to them both will make them stick to one another And then as they grow cold dry these little parts shrink on both sides and by their shrinking draw the bodies together and withal leave greater pores by their being compressed together then were there when by heat and moysture they were dilated into which pores the circumstant cold parts enter and therby as it were wedge in the others and consequently make them hold firmly tostether the bodies which they joyn But if art or nature should apply to this juncture any liquor or vapour which had the nature and power to insinuate it self more efficaciously to one of these bodier then the glew which was between them did of necessity in this case these bodies must fall in pieces And so it happens in the separation of metals by corrosive waters as also in the precipitation of metals or salts when they are dissolv'd into such corrosive waters by means of other metals or salts of a different nature in both which cases the entrance of a latter body that penetrates more strongly and unites it self to one of the joyn'd bodies but not to the other tears them asunder and that which the piercing body rejects falls into little pieces and if formerly it were joyn'd with the liquor 't is then precipitated down from it in a dust Out of which discourse we may resolve the question of that learned and ingenious man Petrus Gassendus who by experience found that water impregnated to fulness with ordinary salt would yet receive a quantity of other salt and when it would imbibe no more of that would neverthless take into it a proportion of a third and so of several kinds of salts one after another which effect he attributed to Vacuities or porous spaces of divers figures that he conceived to be in the water wherof some were fit for the figure of one salt and some for the figure of another Very ingeniously yet if I miss not my mark most assuredly he hath missed his For first how could he attribute divers sorts of Vacuities to water without giving it divers figures And this would be against his own discourse by which every body should have one determinate natural figure Secondly I would ask him if he measured his water after every salting and if he did whether he did not find the quantity greater then before that salt was dissolv'd in it Which if he did as without doubt he must then he might safely conclude that his salts were not receiv'd in vacuities but that the very substance of the water gave them place and so encreas'd by the receiving them Thirdly seeing that in his doctrine every substance has a particular figure we must allow a strange multitude of different shapes of vacuities to be naturally in water if we will have every different substance wherwith it may be impregnated by making decoctions extractions solutions and the like to find a fit vacuity in the water to lodg it self in What a difform net with a strange variety of mashes would this be And indeed how extremely uncapable must it be of the quantity of every various kind of vacuity that you will find must be in it if in the dissolution of every particular substance you calculate the proportion between it and the water that dissolveth it and then multiply it according to the number of several kinds of substances that may be dissolved in water By this proceeding you will find the vacuities to exceed infinitely the whole body of the water even so much that it could not afford subtile thrids enough to hold it self together Fourthly if this doctrine were true it would never happen that one body or salt should precipitate down to the bottom of the water by the solution of another in it which every Alchymist knows never fails in due circumstances for seeing that the body which precipitates and the other which remains dissolv'd in the water are of different figures and therfore require dâ—fferent vacuities they might both of them have kept their places in the water without thrusting one another out of it Lastly this doctrine gives no account why one part of salt is separated from another by being put in the water and why the parts are there kept so separated which is the whole effect of that motion we call dissolution The true reason therfore of this effect is as I conceive that one salt makes the water apt to receive another for the lighter salt being incorporated with the water makes the water more proper to stick to an heavier and by dividing the small parts of it to bear them up that otherwise would have sunk in it The truth and reason of which will appear more plain if at every joynt we observe the particular steps of every
salts solution As soon as you put the first salt into the water it falls down presently to the bottome of it and as the water by its humidity pierces by degrees the little joynts of this salt so the small parts of it are by little and little separated from one another and united to parts of water And so infusing more and more salt this progress will continue till every part of water is incorporated with some part of salt and then the water can no longer work of it self but in conjunction to the salt with which it is united After which if more salt of the same kind be put into the water that water so impregnated will not be able to divide it because it has not any so subtile parts left as are able to enter between the joynts of a salt so closely compacted but may be compared to that salt as a thing of equal driness with it and therfore is unapt to moisten and pierce it But if you put into this compound of salt and water another kind of salt that is of a stronger and drier nature then the former and whose parts are more grosly united then the first salt dissolv'd in the water will be able to get in betwixt the joynts of the grosser salt and divide it into little parts and will incorporate his already-composed parts of salt and water into a decompound of two salts and water till all his parts be anew impregnated with second grosser salt as before the pure water was with the first subtiler salt And so it will proceed on if proportionate bodies be joyn'd till the dissolving composition grow into a thick body To which discourse we may add that when the water is so fully impregnated with the first salt as it will receive no more remaining in the temper 't is in yet if it be heated it will then afresh dissolve more of the same kind Which shews that the reason of its giving over to dissolve is for want of having the water divided into parts little enough to stick to more salt which as in this case the fire doth so peradventure in the other the acrimoniousness of the salt doth it And this is sufficient to give curious wits occasion by making further experiments to Search out the truth of this matter Only we may note what happens in most of the experiencies we have mention'd to wit that things of the same nature joyn better and more easily then others that are more estranged from one another Which is very agreeable to reason seeing that if nature intends to have things consist long together she must fit them for such consistence Which seems to proceed out of their agreement in four qualities First in weight for bodies of divers degrees in weight if they be at liberty seek divers places and consequently substances of like weight must of necessity find one another out and croud together as we have shew'd it is the nature of heat to make them do Now it is apparent that things of one nature must in equal parts have the same or a near proportion ofweight seeing that in their composition they must have the same proportion of Elements The second reason of the consistence of bodies together that are of the same nature is the agreement of their liquid parts in the same degree of rarity and density For as it is the nature of quantity in common to make all parts be one quantity so it is the nature of the degrees of quantity when two parts meet that are of the same degree to make them one in that degree of quantity which is to make them stick together in that degree of sticking which the degree of density that is common to them both makes of its own nature Wheras parts of different densities cannot have this reason of sticking though peradventure they may upon some other ground have some more efficatious one And in this manner the like humide parts of two bodies becomming one the holes or receptacles in which those humide parts are contain'd must also needs be united The third reason is the agreeable proportion which their several figures have in respect of one another For if any humidity be extracted out of a mixed body especially by the virtue of fire it must have left pores of such figures as the humidity that is drawn out of them is apt to be cut into for every humide body not being absolutely humide but having certain dry parts mixed with it is more apt for one kind of figure and greatness then for another and by consequence whenever that humidity shall meet again with the body it was severed from it will easily run through and into it all and fill exactly the cavities pores it passed before The last quality in which bodies that are to consist long together agree is the bigness of the humide dry parts of the same body For if the humide parts be too big for the dry ones 't is clear that the dry ones must needs hang loosly together by them because their glew is in too great a quantity But if the humide parts be too little for the dry on s then of necessity some portion of every little dry part must be unfurnish of glew by means wherof to stick to his fellow and so the sticking parts not being conveniently proportion'd to one another their adhesion cannot be so solid as if each of them were exactly fitted to his fellow CHAP. XVIII Of another motion belonging to particular bodies call'd Atraction and of certain operations term'd Magicall HAving thus ended the two motions of rarefaction and condensation the next that offer themselvs are the locall motions which some bodies have to others These are somtimes perform'd by a plain force in the body towards which the motion is and other whiles by a hidden cause which is not so easily discern'd The first is chiefly that which is ordinarily said to be done by the force of nature to hinder vacuum and is much practis'd by nature as in drawing our breath in sucking and many other natural operations which are imitated by art in making of Pumps Syphons and such other instuments and in that admirable experiment of taking up a heavy Marble stone merely by another lying flat and smoothly upon it without any ther connexion of the two stones together as also by that sport of boyes when they spread a thin moistned leather upon a smooth broad stone press it all over close to it and then by pulling of a string fastned at the middle of the leather they draw up likewise the heavy stone In all which the first cause of the motion proceeds from that body towards which the motion is made and therfore is properly called Attraction For the better understanding and delaring of which let us suppose two marble stones very broad and exceeding smoothly polished to be laid one flat upon the other and let there be a ring fastned at the back part of the
is drawn the more must needs follow Now if there be floating in this air any other atoms subject to the current which the air takes they must also come with it to the fire and by it be rarified and exported out of that little orb Hence it is that men with very good reason hold that fire airs a chamber as we term it that is purifies it both because it purifies it as wind doth by drawing a current of air into it that sweeps through it or by making it purifie it self by motion as a stream of water doth by running as also because those vapours which approach the fire are burned dissolv'd So that the air being noisome and unwholesome by reason of its grossness proceeding from its standing unmoved like a stagnation of dead water in a marish place the fire takes away that cause of annoyance By this very rule we learn that other hot things which participate the nature of fire must likewise in other respects have a resemblance in this quality And accordingly we see that hot loaves in a Bakers shop newly drawn out of the Oven are accounted to draw to them any infection which is in the air The like we say of onyons and other strong breathing substances which by their smel shew much heat in them In like manner 't is conceiv'd that Pigeons and Rabbets and Cats easily take infection by reason of their extraordinary warmth which they have in themselvs And this is confirm'd by the practise of Physitians who use to lay warm Pigeons newly killed to the feet wrists or heads of sick persons and young Puppies to their stomacks and somtimes certain hot gums to their navels to draw out such vapours or humours as infest the body for the same reason they hang amulets of arsenick sublimate dryed Toads or Spiders about their patients necks to draw to them venimous qualities from their bodie Hence also it is that if a man be strucken by a Viper or a Scorpion they use to break the body of the beast it self that stung him if they can get it upon the wound but if the beast be crawl'd out of their finding they do the like by some other venimous creature as I have seen a bruised Toad laid to the biting of a Viper And they manifestly perceive the apply'd body to swel with the Poyson suck'd out from the wound the patient to be reliev'd have less poyson in the same manner as by cupping-glasses the poyson is likewise drawn out from the wound so that you may see the reason of both is the very same or at least very like one another Only we are to note that the proper body of the beast out of which the venome was driven into the wound is more efficacious than any other to suck it out And the like is to be observ'd in all other kinds that such vapours as are to be drawn come better and incorporate faster in bodies of like nature then in those which have only the common conditions of heat and dryness the one of which serves to attract the other to fasten and incorporate into itself the moisture which the first draws to it So we see that water soaks into a dry body whence it was extracted almost inseparably and is hidden in it as when it rains first after hot weather the ground is presently dried after the shower Likewise we see that in most cements you must mingle a dust of the nature of the things which are to be cemented if you will have them bind strongly Out of this discourse we may yield a reason for those Magical operations which some attribute to the Devils assistance peradventure because mans wickedness hath bin more ingenious then his good will and so has found more means to hurt then to help nay when he hath arrived some way to help those very helps have undergone the same calumny because of the likeness which their operations have to the others Without doubt very unjustly if there be truth in the effects For where have we any such good suggestions of the enemy of mankind proposed to us that we may with reason believe he would duly settledly and constantly concur to the help and service of all those he so much hates as he must needs do if he be the Author of such effects Or is it not a wrong to Almighty God and to his careful instruments rather to impute to the Devil the aids which to some may seem supernatural then to them of whom we may justly believe and expect such good Offices and assistances I mean those operations both good and bad which ordinarily are called Magnetical though peradventure wrongfully as not having that property whcih denominates the loadstone One thing I may assure that if the reports be true they have the perfect imitation of nature in them As for example that the Weapons-Salve or the Sympathetick-Powder requires in the using it to be conserved in an equal moderate temper and that the weapon which made the wound or the cloth upon which the blood remains that issued from it be orderly and frequently dressed or else the wounded person will not be cured Likewise the steam or spirits which at the giving of the wound enter'd into the pores of the weapon must not be driven out of it which will be done by fire and so when it is heated by holding over coals you may see a moisture sweat out of the blade at the opposite side to the fire as far as it entred into the wounded persons body which being once all sweated out you shall see no more the like steam upon the sword neither must the blood be washed out of the bloudy cloth for in these cases the powder or salve will work nothing Likewise if there be any excess either of heat or cold in keeping the medicated weapon or cloth the patient feels that as he would do if the like excess where in any remedy that were applyed to the wound it self Likewise if the medicated weapon or bloudy cloth be kept too close no effect follows Likewise the natures of the things used in these cures are of themselves soveraign for healing the like griefs though peradventure too violent if they were apply'd in body without much attenuation And truly if we will deny all effects of this kind we must in a manner renounce all humane faith men of all sorts and qualities and many of them such in my own knowledge as I cannot question their prudence in observing or their sincerity in relating having very frequently made experience of such medicines and all affirming after one fashion to have found the same effects Adde to these the multitude of other like effects appearing or conceited to appear in other things In some Countries 't is a familiar disease with Kine to have a swelling in the soles of their feet and the ordinary cure is to cut a turf upon which they have troden with their sore foot and to hang
in some countries where some one wind has a main predominance and reigns most continually as near the Seashore upon the western coast of England where the South-West wind blows constantly the greatest part of the year may be observed but this effect proceeding from a particular and extraordinary cause concerns not our matter in hand We are to examine the reason of the motion of Restitution which we generally see in young trees and branches of others as we said before In such we see that the earthy part which makes them stiff or rather stark abounds more then in the others that stand as they were bent at least in proportion to their natures but I conceive this is not the cause of the effect we enquire about but that 't is a subtile spirit which hath a great proportion of fire in it For as in rarefaction we found that fire which was either within or without the body to be rarified did cause the rarefaction either by entring into it or by working within it so seeing here the question is for a body to go out of a lesser superficies into a greater which is the progress of rarefaction and hapen's in the motion of restitution the work must needs be done by the force of heat And because this effect proceeds evidently out of the nature of the thing in which it is wrought and not from any outward cause we may conclude it has its origine from a heat within the thing it self or else that was in it and may be press'd to the outward parts of it and would sink into it again As for example when a young tree is bended both every mans conceit is and the nature of the thing makes us believe that the force which brings the tree back again to its figure comes from the inner side that is bent which is compress'd together as being shrunk into a circular figure from a straight one for when solid bodies that were plain on both sides are bent so as on each side to make a portion of a Circle the convex superficies will be longer then it was before when it was plain but the concave will be shorter And therfore we may conceive that the spirits which are in the contracted part being there squeez'd into less room then their nature well brooks work themselvs into a greater space or else that the spirits which are crush'd out of the convex side by the extension of it remain besieging it and strive to get in again in such manner as we have declared when we spoke of attraction wherin we shew'd how the emited spirits of any body will move to their own source and settle again in it if they be within a convenient compass and accordingly bring back the extended parts to their former situation or rather that both these causes in their kinds concur to drive the tree into its natural figure But as we see when a stick is broken 't is very hard to replace all the splinters every one in its proper situation so it must of necessity fall out in this bending that certain insensible parts both inward and outward are therby displaced and can hardly be perfectly rejoynted Whence it follows that as you see the splinters of a half broken stick meeting with one another hold the stick somwhat crooked so these invisible parts do the like in such bodies as after bending stand a little that way but because they are very little ones the tree or branch that has been never so much bended may so nothing be broken in it be set strait again by pains without any notable detriment of its strength And thus you see the reason of some bodies returning in part to their natural figures after the force leaves them that bent them Out of which you may proceed to those bodies that restore themselvs entirely whereof steel is the most eminent And of it we know that there is a fiery spirit in it which may be extracted out of it not only by the long operations of calcining digesting and distilling it but even by gross heating and then extinguishing it in wine and other convenient Liquors as Physicians use to do Which is also confirm'd by the burning of steel-dust in the flame of a candle before it has been thus wrought upon which after-wards it will not do wherby we are taught that originally there are store of spirits in steel till they are sucked out Being then assured that in steel there is such abundance of spirits and knowing that it is the nature of spirits to give a quick motion and seeing that duller spirits in trees make this motion of Restitution we need seek no further what it is that doth it in steel or in any other things that have the like nature which through the multitude of spirits that abound in them especially steel returns back with so strong a jerk that their whole body will tremble a great while after by the force of its own motion By what is said the nature of those bodies which shrink and stretch may easily be understood for they are generally composed of stringy parts to which if humidity happen to arrive they grow therby thicker and shorter As we see that drops of water getting into a new rope of a well or into a new cable will swell it much thicker and by consequence make it shorter Galileus notes such wetting to be of so great efficacy that it will shrink a new cable and shorten it notably notwithstanding the violence of a tempest the weight and jerks of a loaden ship strain it what is possible for them to stretch it Of this nature leather seems to be and parchment and divers other things which if they be proportionably moistned and no exteriour force apply'd to extend them will shrink up but if they be overweted they will become flaccide Again if they be suddenly dryed they 'l shrivel up but if they be fairly dried after moderate weting they will extend themselvs again to their first length The way having been open'd by what we have discoursed before we came to the motion of Restitution towards the discovery of the manner how heavy bodies may be forced upward contrary to their natural motion by very smal means in outward appearance let us now examine upon the same grounds if like motions to this of water may not be done in some other bodies in a subtiler manner In which more or less needs not trouble us since we know that neither quantitâ—â—or the operations of it consist in an indivisible or are limited or determin'd by periods they may not pass 'T is enough for us to find a ground for the possibility of the operation and then the perfecting and reducing of it to such a height as at first might seem impossible incredible we may leave to the Oeconomy of wise nature He that learns to read write or play on the Lute is in the beginning ready to lose heart at every step
the air in this our Hemisphere is as it were strew'd over and sow'd with abundance of Northern atoms and that some brooks of them are in station others in a motion of retrogradation back to their own North Poles the Southern atoms which coming upon them at the Equator do not only press in among them wherever they can find admittance but also go on forwards to the North Poles in several files by themselvs being driven that way by the same accidental causes which make the others retire back seizing in their way upon the northern ones in such manner as we described in filtration and therby creeping along by them wherever they find them standing stil and going along with them wherever they find them going back must of necessity find passage in great quantites towards and even to the North Pole though some parts of them will ever and anon be check'd in this their journey by the main current prevailing over some accidental one and so be carried back again to the Equator whose line they had crossed And this affect cannot choose but be more or less according to the seasons of the year For when the Sun is in the Tropick of Capricorn the southern atoms will flow in much more abundance and with far greater speed into the Torrid Zone then the northern atoms can by reason of the Suns approximation to the South and his distance from the North Pole since he works faintest where he is furthest off and therfore from the North no more emanations or Atoms will be drawn but such as are most subtilised and duly prepared for that course And since only these selected bands do now march towards the Equator their files must needs be thinner then when the Suns being in the Equator or Tropick of Cancer wakens and musters up all their forces And consequently the quiet parts of air between their files in which like Atoms are also scatter'd are the greater wherby the advenient Southern Atoms have the larger filter to climb up by And the like happens in the other Hemisphere when the Sun is in the Tropick of Cancer as who will bestow the pains to compare them will presently see Now then let us consider what these two streams thus incorporated must of necessity do in the surface or upper parts of the Earth First 't is evident they must needs penetrate a pretty depth into the Earth for so freezing perswades us and much more the subtile penetration of divers more spiritual bodies of which we have sufficiently discoursed above Now let us conceive that these steams find a body of a convenient density to incorporate themselvs in in the way of density as we see fire doth in iron and in other dense bodies and this not for an hour or two as happens in fire but for years as I have been told that in the extreme cold hills in the Peak in Darbyshire happens to the dry Atoms of cold which are permanently incorporated in water by long continual freezing and so make a kind of Chrystal In this case certainly it must come to pass that this body will become in a manner wholly of the nature of these steams which being drawn from the Poles that abound in cold and driness for others that have not these qualities do not contribute to the intended effect the body is aptest to become a stone for so we see that cold and drought turns the superficial parts of the earth into stones rocks accordingly wherever cold dry winds reign powerfully all such Countries are mainly rocky Now then let us suppose this stone to be taken out of the earth and hang'd in the air or set conveniently on some little pin or otherwise put in liberty so as a small impulse may easily turn it any way it will in this case certainly follow that the end of the stone which in the earth lay towards the North pole will now in the air convert it self in the same manner towards the same point and the other end which lay towards the South turn by consequence to the South I speak of these Countries which lie between the Equator and the North in which of necessity the stream going from the North to the Equator must be stronger then the opposite one Now to explicate how this is done Suppose the stone hang'd East and West freely in the air the steam which is drawn from the North Pole of the earth ranges along by it in its course to the Equator and finding in the stone the South steam which is grown innate to it very strong it must needs incorporate it self with it and most by those parts of the steam in the stone which are strongest which are they that come directly from the North of the stone by which I mean that part of the stone that lay Northward in the Earth and that still looks to the North pole of the Earth now it is in the air And therfore the great floud of atoms coming from the North pole of the earth will incorporate it self most strongly by the North end of the stone with the little floud of Southern atomes it findes in the stone for that end serves for the coming out of the Southern atomes and sends them abroad as the South end doth the Northern steam since the steams come in at one end and go out at the other From hence we may gather that this stone will joyn and cleave to its attractive whenever it happens to be within the Sphere of its activity Besides if by some accident it should happen that the atomes or steams which are drawn by the Sun from the Polewards to the Equator should come stronger from some part of the earth which is on the side hand of the Pole then from the very Pole it self in this case the stone will turn from the Pole towards that side Lastly whatever this stone will do towards the Pole of the earth the very same a lesser stone of the same kind will do towards a greater And if there be any kind of other substance that has participation of the nature of this stone such a substance will behave it self towards this stone in the same manner as such a stone behaves it self towards the earth all the Phenomens whereof may be the more plainly observed if the stone be cut into the form of the earth And thus we have found a perfect delineation of the Loadstone from its causes For there is no man so ignorant of the nature of a Loadstone but he knows that the properties of it are to tend towards the North to vary somtimes to joyn with another Loadstone to draw iron to it and such like whose causes you see deliver'd But to come to experimental proofs and observations on the Loadstone by which it will appear that these causes are well esteem'd and apply'd we must be beholding to that admirable searcher of the nature of the Loadstones Dr. Gilbert by means of
of them To come then to the matter Now that we have explicated the natures of those motions by means wherof bodies are made and destroy'd and in which they are to be consider'd chiefly as passive whiles some exterior agent working upon them causes such alterations in them and brings them to such pass as we see in the changes that are daily wrought among substances The next thing we are to imploy our selves about is to take a survey of those motions which some bodies have wherin they seem to be not so much patients as agents and contain within themselvs the principle of their own motion having no relation to any outward object more then to stir up that principle of motion and set it on work which when it is once in act hath as it were within the limits of its own kingdom and sever'd from commerce with all other bodies whatever many other subaltern motions over which it presides To which purpose we may consider that among the compounded bodies whose natures we have explicated there are some in whom the parts of different complexions are so small so wel mingled together that they make a compound which to our sense seems all quite through of one Homogeneous nature and however it be divided each part retains the entire and compleat nature of the whole Others again there are in which 't is easie to discern that the whole is made up of several great parts of very differing natures and tempers And of these there are two kinds one of such as their differing parts seem to have no relation to one another or correspondence together to perform any particular work in which all of them are necessary but rather they seem to be made what they are by chance and accident and if one part be sever'd from another each is an entire thing by it self of the same nature as it was in the whole and no harmony is destroy'd by such division As may be observ'd in some bodies dig'd out of Mines in which one may see lumps of Metal or stone and glass and such different substances in their several distinct situations perfectly compacted into one continuate body which if you divide the glass remains what it was before the Emerald is still an Emerald the silver is good silver and the like of the other substances the causes of which may be easily deduced out of what we have formerly said But there are other bodies in which this manifest and notable difference of parts carries with it such a subordination of one of them to another as we cannot doubt but that nature made such engines if so I may call them by design and intended that this variety should be in One thing whose unity and being what it is should depend of the harmony of the several differing parts and should be destroy'd by their separation As we see in living Creatures whose particular parts and members being once sever'd there is no longer a living creature to be found among them Now of this kind of bodies there are two sorts The first is of those that seem to be one continuate substance wherin we may observe one and the same constant progress throughout from the lowest to the highest part of it so that the operation of one part is not at all different from that of another but the whole body seems to be the course and throughfare of one constant action varying it self in divers occasions and occurrences according to the disposition of the subject The bodies of the second sort have their parts so notably separated one from the other and each have such a peculiar motion proper to them that one might conceive they were every one a complete distinct total thing by it self and that all of them were artificially tied together were it not that the subordination of these parts to one another is so great and the correspondence between them so strict the one not being able to subsist without the other from whom he derives what is needful for him and again being so useful to that other and having its action and motion so fitting and necessary for it as without it that other cannot be as plainly convinces that the compound of all these several parts must needs be one individuol thing I remember that when I travel'd in Spain I saw there two Engines that in some sort express the natures of these two kinds of bodies One at Toledo the other a Segovia both of them set on work by the current of the river in which the foundation of their machine was laid That at Toledo was to force up water at a great height from the river Tagus to the Alcazar the Kings palace that stands upon a high steep hill or rock almost perpendicular over the river In the bottome there was an indented wheel which turning round with the stream gave motion at the same time to the whole engine which consisted of a multitude of little troughs or square ladles set one over another in two parallel rows over against one another from the bottom to the top and upon two several divided frames of timber These troughs were closed at one end with a traverse board to retain the water from running out there which end being bigger then the rest of the trough made it somewhat like a ladle and the rest of it seem'd to be the handle with a channel in it the little end of which channel or trough was open to let the water pass freely away And these troughs were fasten'd by an axletree in the middle of them to the frame of timber that went from the bottome up to the top so that they could upon that center move at liberty either the shut end downwards or the open end like the beam of a ballance Now at a certain position of the root-wheel if so I may call it all one side of the machine sunk down a little lower towards the water and the other was raised a little higher Which motion was changed as soon as the ground-wheel had ended the remnant of his revolution for then the side that was lowest before sprung up and the other sunk down And thus the two sides of the machine were like two legs that by turns trod the water as in the Vintage men press Grapes in a watte Now the troughs that were fast'ned to the timber which descended turn'd that part of them downwards which was like a Box shut to hold the water and consequently the open end was up in the air like the arm of the ballance to which the lightest scale is fasten'd and in the mean time the troughs upon the ascending timber were moved by a contrary motion keeping their boxends aloft and letting the open ends incline downwards so that if any water were in them they would let it run out wher'as the others retain'd any that came into them VVhen you have made an image of this Machine in your phantasie consider what will follow out
of its motion You will perceive that when one leg sinks down towards the water that trough which is next to the Superficies of it putting down his box end and dipping it a little in the water must needs bring up as much as it can retain when that leg ascends which when it is at its height the trough moves upon his own centre the box end which was lowest becomes now highest and so the water runs out of it Now the other leg descending at the same time it falls out that the trough on its side which would be a step above that which hath the water in it if they stood in equilibrity becomes now a step lower then it and is so placed that the water which runs out of that which is aloft falls into the head or box of it which no sooner hath receiv'd it but that leg on which it is fastned springs up and the other descends so that the water of the second leg runs now into the box of the first leg that is next above that which first laded the water out of the river And thus the troughs of the two legs deliver their water by turns from one side to the other and at every remove it gets a step upwards till it comes to the top whiles at every ascent and descent of the whole side the lowest ladle or trough takes new water from the River which ladleful follows immediately in its ascent that which was taken up the time before And thus in a little while all the troughs from the bottom to the top are full unless there happen to be some failing in some ladle and in that case the water breaks out there and all the ladles above that are dry The other Engine or rather multitude of several engines to perform sundry different operations all conducing to one work wheras that of Toledo is but one tenour of motion from the first to the last is in the Mint at Segovia Which is so artificially made that one part of it distends an Ingot of Silver or Gold into that breadth and thickness as is requisite to make Coyn of Which being done it delivers the plate it has wrought to another that Prints the Figure of the Coyn upon it And from thence it is turn'd over to another that cuts it according to the Print into due shape and weight And lastly the several pieces fall into a reserve in another room where the Officer whose charge it is findes Treasure ready Coyned without any thing there to inform him of the several different motions that the silver or the gold passed before they came to that state But if he go on the other side of the wall into the room where the other machines stand and are at work he will then discern that every one of them which consider'd by it self might seem a distinct complete engine is but a serving part of the whole whose office is to make money and that for this work any one of them separated from the rest ceases to be the part of a mint and the whole is malm'd and destroy'd Now let us apply the consideration of these different kinds of Engines to the natures of the bodies we treat of Which I doubt not would fit much better were they lively and exactly described But it is so long since I saw them and I was then so very young that I retain but a confused and cloudy remembrance of them Especially of the mint at Segovia in the which there are many more particulars then I have touched as conveniency for refining the ore or metal and then casting it into ingots and driving them into rods and such like to all which there is little help of hands requisite more then to apply the matter duly at the first But what have I said of them is enough to illustrate what I aim at and though I should erre in the particulars 't is no great matter for I intend not to deliver the history of them but only out of the remembrance of such noteful and artificial masterpieces to frame a model in their phancies that shall read this of something like them wherby they may with more ease make a right conception of what we are handling Thus then all sorts of plants both great and small may be compared to our first engine of the waterwork at Toledo For in them all the motion we can discern is of one part transmitting to the next to it the juyce received from that immediately before it so that it hath one constant course from the root which sucks it from the earth to the top of the highest spring in which if it should be intercepted and stopt by any maiming of the bark the channel it ascends by it would there break out and turn into drops or gum or some such other substance as the nature of the plant requires and all that part of it to which none of this juice can ascend would dry and wither and grow dead But Sensible living creatures we may fitly compare to the second machine of the Mint at Segovia For in them though every part and member be as it were a complete thing of it self yet every one requires to be directed and put on in its motion by another and they must all of them though of very different natures and kinds of motion conspire together to effect any thing that may be for the use and service of the whole And thus we find in them perfectly the nature of a mover and a moveable each of them moving differently from one another and framing to themselvs their own motions in such sort as is most agreeable to their nature when that part which sets them on work hath stir'd them up And now because these parts the movers and the moved are parts of one whole we call the entre thing Automatum or seâ—movens or a Living Creature Which also may be fitly compared to a Joyner or a Painter or other craftsman that had his tools so exactly fitted about him as when he had occasion to do any thing in his trade his tool for that action were already in the fittest position for it to be made use of so as without removing himsef from the place where he might sit invironed with his tools he might by only pulling of some little cords either apply the matter to any remote tool or any of his tools to the matter he would work upon according as he findes the one or the other more convenient for performance of the actions he intends Wheras in the other there is no variety of motions but one and the same goes quite through the body from one end of it to the other and the passage of the moisture through it from one part to another next which is all the motion it hath is in a manner but like the rising of water in a Stil which by heat is made to creep up by the sides of the glass and from thence runs
of necessity be more humid and figurable then that of an ordinary plant and the Artificer which works and moulds it must be more active Wherfore we must suppose that the mass of which an Animal is to be made must be actually liquid and the fire that works upon it must be so powerful that of its own nature it may be able to convert this liquid matter into such breaths and steams as we see use to rise from water when the Sun or fire works upon it Yet if the mass were altogether as liquid as water it would vanish away by heat boyling it and be dried up therfore it must be of such a convenient temper that although in some of its parts it be fluid and apt to run yet by others it must be held together as we see that unctuous things for the most part are which will swell by heat but not fly away So then if we imagine a great heat to be imprison'd in such a liquor and that it seeks by boyling to break out but that the solidness and viscousness of the substance will not permit it to evaporate it cannot chuse but comport it self in some such sort as we see butter or oyl in a frying-pan over the fire when it rises in bubbles but much more efficaciously For their body is not strong enough to keep in the heat and therfore those bubbles fall again wheras if it were those bubbles would rise higher and higher and stretch themselvs longer and longer as when the Soap-boylers boyl a strong unctuous lye into Soap and every one of them would be as it were a little brook wherof the channel would be the enclosing substance and the inward smoak that extends it might be compared to the water of it as when a glass is blown out by fire and air into a long figure Now we may remember how we have said where we treated of the Production and Resolution of Mixed bodies that there are two sorts of liquid substantial parts which by the operation of fire are sent out of the body it works upon the watery and the oyly parts For thouh there appear somtimes some very subtile and Ethereal parts of a third kind wich are the Aquae Ardentes or borning spirits yet in such a close distilling of circulation as this is they are not sever'd by themselvs but accompany the rest and especially the watery parts which are of a nature that the rising Ethereal spirits easily mingle with and extend themselves in it wherby the water becomes more efficacious and the spiritt less fugitive Of these liquid parts which the fire sends away the watry ones are the first as being the easiest to be raised the oyly parts rise more difficultly and therfore come last And in the same manner it happens in this emission of brooks the watry and oyly steams will each of them fly into different reservs and if there arrive to them abundance of their own quality each of them must make a substance of its own nature by by setling in a convenient place and by due concoction Which substance after it is made and confirm'd if more humidity and heat press it will again break forth into other little channels But when the watry and oyly parts are boyl'd away there remain yet behind other more solid and fixed parts and more strongly incorporated with fire then either of these which yet cannot drie up into a fiery salt because a continual accession of humour keeps them always flowing and so they become like a cauldron of boyling fire Which must propagate it self as wide as either of the other since the activity of it must needs be greater then theirs as being the source of motion to them and that there wants not humidity for it to extend it self by And thus you see three roots of three divers plants all in the same plant proceeding by natural resolution from one primitive source Wherof that which is most watry is fittest to fabricate the body and common outside of the triformed plant since water is the most figurable principle in nature and most susceptible of multiplication and by its cold is easiest to be hardned and therfore fittest to resist the injuries of enemy-bodies that may infest it The oily parts are fittest for the continuance and solidity of the plant for we see that viscuosity and oyliness hold together the parts where they abound and they are slowly wasted by fire but conserve and are an aliment to the fire that consumes them The parts of the third kind are fittest for the conservation of heat which though in them it be too violent yet is necessary for working upon other parts and maintaining a due temper in them And thus we have armed our plant with three sorts of rivers or brooks to run through him with as many different streams the one of a gentle balsamike oyle another of streaming fire and the third of a con-natural and cooler water to irrigate and temper him The streams of water as we have said must run through the whole fabrick of this triformed plant and because it is not a simple water but warm in a good degree and as it were a middle substance betwixt water and air by reason of the ardent volatile spirit that is with it 't is of a fit nature to swell as air doth and yet withall to resist violence in a convenient degree as water doth Therfore if from its source nature sends abundance into any one part that part must swell and grow thicker and shorter and so must be contracted that way which nature has order'd it Whence we perceive a means by which nature may draw any part of the outward fabrick which way soever she is pleased by set instruments for such an effect But when there is no motion or but little in these pipes the standing stream that is in a very little though long channel must needs be troubled in its whole body if any one part of it be press'd upon so as to receive therby any impression and therfore whatever is done upon it though at the very furthest end of it makes a commotion and sends an impression up to its very source Which appearing by our former d scourse to be the origine of particular and accasional motion 't is obvious to conceive how it is apt to be moved and wrought by such an impression to set on foot the begining of any motion which by natures providence is convenient for the plant when such an impression is made upon it And thus you see this plant hath the virtue both of sense or feeling that is of being moved and effected by extern objects lightly striking upon it as also of moving it self to or from such an object according as nature shall have ordain'd Which in sum is that This Plant is a Sensitive Creature composed of three sources the Heart the Brain and the Liver whose off-springs are the Arteries the Nervs and the Veins which are fil'd with Vital
in the seed must needs be the principal immediate cause of this admirable effect This latter then being supposed our labour and endeavour will be to unfold as far as so weak and dim eyes can reach the excellency and exactness of Gods Providence which cannot be enough adored when it is reflected on and mark'd in the apt laying of adequate causes to produce such a figure out of such a mixture first laid From them so artificially ranged we shall see this miracle of nature to proceed and not from an immediate working of God or nature without convenient and ordinary instruments to mediate and effect this configuration through the force and virtue of their own particular natures Such a necessity to interest the chief workman at every turn in particular effects would argue him of want of skill and providence in the first laying of the foundations of his designed Machine He were an improvident Clockmaker that should have cast his work so as when it were wound up and going it would require the Masters hand at every hour to make the Hammer strike upon the Bell. Let us not then too familiarly and irreverently ingage the Almighty Architect's immediate handy-work in every particular effect of nature Tali non est dignus vindice noduâ— But let us take principles within our own kenning and consider how a body hath of its own nature three dimensions as Mathematicians use to demonstrate and that the variety we see of figures in bodies proceeds out of the defect of some of these dimensions in proportion to the rest As for example that a thing be in the form of a Square Tablet is for that the cause which gave it length and breadth could not also give it thickness in the same proportion for had it been able to give profundity as well as the other two it had made a Cube instead of a Tablet In like manner the former of a lamine or very long square is occasion'd by some accident which hinders the cause from giving breadth and thickness proportionable to the length And so other figures are made by reason that their causes are some ways bound to give more of some dimension to one part then another As for example when water falls out of the skie it hath all the little corners or extancies of its body grated off by the air as it rolls and tumbles down in it so that it becomes round and continues in that form till setling on some flat body as Grass or a Leaf it receives a little plainness to the proportion of his weight mastering the continuity of it And therfore if the drop be great upon that plain body it seems to be half a Sphere or some less portion of one but if it be a little drop then the flat part of it which is that next the grass is very little and undiscernable because it hath not weight enough to press it much and spread it broad upon the grass and so the whole seems in a manner to be a Sphere But if the extern causes had press'd upon this drop only broadways and thick ways as when a Turner makes a round Pillar of a square one then it would have proved a Cylinder nothing working upon it to grate off any of its length but only the corners of the breadth and thickness of it And thus you see how the fundamental figures upon which all the rest are grounded are contrived by nature not by the work of any particular Agent that immediately Imprints a determinate figure into a particular body as though it wrought it there at once according to a foreconceiv'd design or intelligent aim of producing such a figure in such a body but by the concurrence of several accidental causes that all joyn in bringing the body they file and work upon into such a shape Only we had like to have forgotten the reason and cause of the concave figure in some parts of Plants which in the ordinary course of nature we shall find to grow from hence That a round outside being filled with some liquor which makes it grow higher and higher it happens that the succeeding causes contract this liquor and harden the outside and then of necessity there must be a hollow Cylinder remaining in lieu of the juice which before fill'd it As we see every day in corn and in Reeds and in Canes and in the stalks of many herbs which whilst they are tender and in their first growth are full of juice and become afterwards hallow and dry But because this discourse may peradventure seem too much in common it will not be amiss to apply it to some particulars that seem very strange And first let us examine how the rocking of concrete juices which seems to be such an admirable mystery of Nature is performed Allom falls down in lumps Saltpeter in long icicles and common Salt in squares and this not once or somtimes now or then but always constantly in the same order The reason of these effects will easily be deduced out of what we have said For if all three be dissolv'd in the same water Allom being the grossest falls first and fastest and being of an unctious nature the first part which falls doth not harden till the second comes to it wherby this second sticks to the first and crushes it down and this is serv'd in the same manner by the third and so it goes on one part squeezing another till what is undermost grow hard enough to resist the weight of new falling parts or rather till no more fall but the liquor they were dissolv'd in is deliver'd of them all and then they harden in that figure they were compress'd into As for Salt which descends in the second place that swims first upon the water and there gets its figure which must be equally long and broad because the water is indifferent to those two positions but its thickness is not equal to its other two dimensions by reason that before it can attain to that thickness it grows too heavy to swim any longer and after it is encreas'd to a certain bulk the weight of it carries it down to the bottom of the water and consequently it can encrease no more for it encreases by the joyning of little parts to it as it swims on the top of the water The Saltpeter falls last which being more difficult to be figured then the other two because it is more dry then either of them as consisting chiefly of earthy and of fiery parts is not equally encreased neither in all three nor in two dimensions but hath its length exceeding both its breadth and thickness and its lightness makes it fall last because it requires least water to sustain it To give the causes of the figures of divers mixts and particularly of some precious stones which seems to be cast by Nature in exactest moulds would oblige us to enter into the particular manner of their generation which were exceeding hard if
we have of things without us give names to them according to the passions and affections which those things cause in our senses which being the same in all mankind as long as they are consider'd in common and their effects are look'd upon in gross all the world agrees in one Notion and Name of the same thing for every man living is affected by it just as his neighbour is and as all men else in the world are As for example Heat or Cold works the same feeling in every man composed of flesh and bloud and therfore whoever should be ask'd of them would return the same answer that they cause such and such affects in his sense pleasing or displeasing to him according to their degrees and as they tend to the good or evil of his whole body But if we descend to particulars we shall find that several men of differinâ— constitutions frame different notions of the same things according as they are conformable or disagreeing to their natures and accordingly they give them different names As when the same liquor is sweet to some mens tast which to anothers appears bitter one man takes that for a perfume which to another is an offensive smel In the Turkish Baths where there are many degrees of heat in divers rooms through all which the same person uses to pass and to stay a while in every one of them both at his entrance and going out to season his body by degrees for the contrary excess he is going to that seems chilly-cold at his first return which appear'd melting hot at his going to it as I my self have often made experience in those Countreys Beauty and loveliness will shine to one man in the same face that will give aversion to another All which proclaims that the Sensible Qualities of Bodies are not any positive real thing consisting in an indivisible and distinct from the body it self but are meerly the very body as it affects our senses to discover how they do which must be our labour here Let us therfore begin with considering the difference between sensible and insensible creatures These later lie exposed to the mercy of all outward agents that from time to time by the continual motion which all things are in come within distance of working upon them and they have no power to remove themselvs from what is averse to their nature nor to approach nearer what comforts it But the others having within themselvs a principle of motion as we have already declared are able whenever such effects are wrought on them as on the others upon their own account and by their own action to remove themselvs from what begins to annoy them and to come nearer to what they find a beginning of good by These impressions are made on those parts of us which we call the Organs of our Senses and by them give us seasonable advertisements and knowledges wherby we may govern and order to the best advantage our little charge of a body according to the tune or warnings of change in the great circumstant body of the world as far as it may concern ours Which how it is done and by what steps it proceeds shall be in the following discourse laid open Of this great machine that environs us we who are but a small parcel are not immediately concern'd in every part It imports not us for the conservation of our body to have knowledge of other parts then such are within the distance of working upon us those only within whose sphere of activity we are planted can offend or advantage us and of them some are near us others further from us Those that are next us we discern according as they are qualified either by our Touch or our Tast or our Smelling which three Senses manifestly appear to consist in a meer gradation of more or less gross and their operations are level'd to the three Elements that press upon us Earth Water and Air. By our other two Senses our Hearing and our Seeing we have notice of things further off and the agents which work on them are of a more refined nature But we must treat of them all in particular and that which we will begin with shall be the Touch as being the grossest of them and that which converses with none but the most material and massie objects We see it deals with heavy consistent bodies and judges of them by conjunction to them and by immediate reception of something from them And according to the divers impressions they make in it it distinguishes them by divers names which as we said of the qualities of mixed bodies are generally reduced to certain pairs as hot and cold wet and dry soft and hard smooth and rough thick and thin and some others of the like nature which were needless to enumerate since we pretend not to deliver the science of them but only to shew that they and their actions are all corporeal And this is sufficiently evident by meer repenting but their very names for 't is plain by what we have already said that there are nothing else but certain effections of quantity arising out of different degrees of rarity and density compounded together And 't is manifest by experience that our sense receivs the very same impressions from them which another body doth For our body or our sense will be heated by fire burned by it too if the heat be too great as well as wood it will be constipated by cold water moistened by humide things and dryed by dry bodies in the same manner as any other body whatever Likewise it may in such sort as they be wounded and have its continuity broken by hard things be pleas'd and polish'd by soft and smooth be press'd by thick and heavy and rub'd by those that are rugged c. So that those Masters who will teach us that the impressions upon sense are made by spiritual or spirit-like things or qualities which they call intentional specieses must labour at two works the one to make it appear that there are in nature such things as they would perswade us the other to prove that these material actions we speak of are not able to perform those effâ—cts for which the senses are given to living creatures And till they have done that I conceive we should be much too blame to admit such things as we neither have ground for in reason nor can understand what they are And therfore we must resolve to rest in this belief which experience breeds in us that these bodies work on our senses no other ways then by a corporeal operation and that such a one is sufficient for all the effects we see proceed from them as in the process of this discourse we shall more amply declare The Element immediately next to Earth in grosness is Water And in it is the exercise of our tast or Mouth being perpetually wet within by means of which moysture our Tongue receives into it some
evident that white which is the chiefest colour reflects most light and as evident that black reflects least light so that it reflects shadows in lieu of colours as the Obsidian stone among the Romanes witness as also that to be dense and hard and of small parts is the disposition of the object which is most apt to reflect light we cannot doubt but that white is that disposition of the superficies That is to say It is the superficies of a body consisting of dense of hard and of small parts and on the contrary side black is the disposition of the superficies which is most soft and full of greatest pores for when light meets with such a superficies it gets easily into it and is there as it were absorpt and hidden in caves and comes not out again to reflect towards our eye This doctrine of ours of the Generation of Colours agrees exactly with Aristotles principles and follows evidently out of his definitions of Light and of Colours And for suming up the general sentiments of mankinde in making his Logical definitions I think none will deny his being the greatest Master that ever was He defines Light to be actus Diaphani which we may thus explicate It is that thing which makes a body that hath an aptitude or capacity of being seen quite through in every interior part of it to be actually seen quite through according to that capacity of it And he defines Colours to be The term or ending of a diaphanous body the meaning wherof is That Colour is a thing which makes a diaphanous body reach no further or the cause why a body is no further diaphanous then till where it begins or that Colour is the reason why we can see no further then to such a degree through or into such a body Which definition fits most exactly with the thing it gives us the nature of For 't is evident that when we see a body the body we see hinders us from seeing any other that is in a straight line beyond it and therfore it cannot be denied but that Colour terminates and ends the diaphaneity of a body by making it self be seen And all men agree in conceiving this to be the nature of Colour and that it is a certain disposition of a body wherby that body comes to be seen On the other side nothing is more evident then that to have us see a body light must reach from that body to our eye Then adding to this what Aristotle teaches concerning the producton of seeing which he sayes is made by the action of the seen body upon our sense it follows that the object must work upon our sense either by light or at least with light for light rebounding from the object round about by straight lines some part of it must needs come fom the object to our eye Therfore by how much an object sends more light to our eye by so much that object works more upon it Now seeing that divers objects send light in divers manners to our eye according to the divers natures of those objects in regard of hardness density and littleness of parts we must agree that such bodies work diversly and make different motions or impressions upon our eye and consequently the passion of our eye from such objects must be divers But there is no other diversity of passion in the eye from the object in regard of seeing but that the object appear divers to us in point of Colour Therfore we must conclude That divers bodies I mean divers or different in that kind we hear talk of must necessarily seem to be of divers colours meerly by the sending of light to our eye in divers fashions Nay the very same object must appear of different colours whenever it happens that it reflects light differently to us As we see in Cloth if it be gather'd together in foulds the bottoms of those foulds shew to be of one kind of colour and the tops of them or where the cloth is stretch'd out to the full percussion of light appears to be of another much brighter colour And accordingly Painters are fain to use almost opposite colours to express them In like manner if you look upon two pieces of the same cloth or plush whose grains lie contrariwise to one another they will likewise appear to be of different colours Both which accidents and many other like them in begetting various representations of Colours arise out of lights being more or less reflected from one part then from another Thus then you see how Colour is nothing else but the disposition of the bodies superficies as it is more or less apt to reflect light since the reflection of light is made from the superficies of the seen body and the variety of its reflection begets variety of colours But a superficies is more or less apt to reflect light according to the degrees of its being more or less penetrable by the force of light striking upon it For the rays of light that gain no entrance into a body they are darted upon must of necessity fly back again from it But if light gets entrance and penetrates into the body it either passes quite through it or else it is swallow'd up and lost in that body The former constitutes a diaphanous body as we have already determin'd and the semblance which the latter will have in regard of colour we have also shew'd must be black But let us proceed a little further We know that two things render a body penetrable or easie to admit another body into it Holes such as we call pores and softness or humidity so that driness hardness and compactedness must be proproperties which render a body impenetrable And accordingly we see that if a diaphanous body which suffers light to run through it be much compress'd beyond what it was as when water is compress'd into ice it becomes more visible that is reflects more light and consequently it becomes more white for white is that which reflects more light On the contrary side softness unctuousness and viscousness encreases blackness As you may experience in oyling or greasing of Wood which before was but brown for therby it becomes more black by reason that the unctuous parts added to the other more easily then they single admit into them the light that sticks upon them and when it is gotten in it is so entangled there as though the wings of it were bird-limed over that it cannot flie out again And thus it is evident how the origine of all colours in bodies is plainly deduced out of the various degrees of rarity and density variously mixed and compounded Likewise out of this discourse the reason is obvious why some bodies are diaphanous and others are opacous for since it falls out in the constitution of bodies that one is composed of greater parts then another it must needs happen that light be more hindred in passing through a body composed of bigger
parts then another whose parts are less Neither doth it import that the pores be supposed as great as the parts for be they never so large the corners of the thick parts they belong to must needs break the course of what will not bow but goes all in straight lines more then if the parts and pores were both less since for so subtile a piercer as light no pores can be too little to give it entrance 'T is true such great ones would better admit a liquid body into them such a one as water or air but the reason of that is because they will bow and take any ply to creep into those cavities if they be large enough which light will not do Therefore 't is clear That freedom of passage can happen to light only there where there is an extreme great multitude of pores and parts in a very little quantity or bulk of body which pores and parts must consequently be extreme little ones for by reason of their multitude there must be great variety in their situation from whence it will happen that many lines must be all of pores quite through and many others all of parts although the most will be mixed of both pores and parts And so we see that although the light pass quite through in many places yet it reflects from more not onely in the superficies but in the very body it self of the Diaphanous substance But in another substance of great parts and pores there can be but few whole lines of pores by which the light may pass from the object to make it be seen and consequently it must be Opacous which is the contrary of Diaphanous that admits many Rays of Light to passe through it from the Object to the Eye wherby It is seen though the Diaphanous hard body intervene between them Now if we consider the generation of these two Colours White and black in bodies we shall find that likewise to justifie and second our doctrine For white things are generally cold and dry and therfore are by nature ordain'd to be receptacles and conservers of heat and of moisture as Physitians note Contrariwise Black as also green which is near of kin to black are growing colours and are the die of heat incorporated in abundance of wet as we see in smoak in pit-coal in garden ground and in Chymical putrefactions all which are black as also in young herbs which are generally green as long as they are young and growing The other colours keeping their standing betwixt these are generated by the mixture of them and according as they partake more or less of either of them are nearer or further off from it So that after all this discourse we may conclude in short that The colour of a body is nothing else but the power which that body hath of reflecting light to the eye in a certain order and position and consequently is nothing else but the very superficies of it with its asperity or smoothness with its pores or inequalities with its hardness or softness and such like The Rules and limits wherof if they were duly observ'd and order'd the whole nature and science of colours would easily be known and described But out of this little we have deliver'd of this subject it may be rightly inser'd that Real Colours proceed from Rarity and Density as even now we touch'd and have their head spring there and are not strange qualities in the air but tractable bodies on the earth as all are which as yet we have found and medled withal and are indeed the very bodies themselves causing such effects upon our eye by reflecting of light which we express by the names of Colours CHAP. XXX Of Luminous or apparent Colours AS for the Luminous Colours whose natures Art hath made more maniable by us than those which are called real Colours and are permanent in bodies their generation is clearly to be seen in the Prism or Triangular glass we formerly mention'd The considering of which will confirm our doctrine That even the colours of bodies are but various mixtures of light and shadows diversly reflected to our eyes For the right understanding of them we are to note That this glass makes apparitions of colours in two sorts one when looking through it there appear various colours in the objects you look on different from their real ones according to the position you hold the glass in when you look on them The other sort is when the beams of light that pass through the Glass are as it were tincted in their passage and are cast by the Glass upon some solid object and appear there in such and such colours which continue still the same in what position soever you stand to look upon them either before or behind or on any side of the Glass Secondly we are to note that these colours are generally made by refraction though somtimes it may happen otherwise as above we have mention'd To discover the reason of the first sort of colours that appear by refraction when one looks through the glass let us suppose two several bodies one black the other white lying close by one another and in the same horisontal parallel but so that that the black be further from us then the white then if we hold the Prism through which we are to see these two oppositely coloured bodies somwhat above them and that side of it at which the coloured bodies must enter into the glass to come to our eye parallel to those bodies 't is evident That the black will come into the Prism by lesser angles then the white I mean that in the line of distance from that face of the glass at which the colours come in a longer line or part of black will subtend an angle no bigger then a lesser line or part of white doth subtend Thirdly we are to note That from the same point of the object there come various beams of light to that whole superficies of the glass so that it may and somtimes doth happen that from the some part of the object beams are reflected to the eye from several parts of that superficies of the glass at which they enter And whenever this happens the object must necessarily be seen in divers parts that is the picture of it will at the same time appear to the eye in divers places And particularly we may plainly observe two pictures one a lively and strong one the other a faint and dim one Of which the dim one will appear nearer us then the lively one and is caus'd by a secondary ray or rather I should say by a longer ray that striking nearer to the hither edge of the glasses superficies which is the furthest from the object makes a more acute angle then a shorter ray doth that strikes upon a part of the glass further from our eye but nearer the object and therfore the image made by this secondary or longer ray must appear
of extancies as our modern Astronomers shew when they give an account of theface as some call it in the Orbe of the Moon Likewise in regard of soft or of resistent parts light will be reflected by them more or less strongly that is more or less mingled with darkness For whereas it rebounds smartly back if it strikes not upon a hard and a resistent body and accordingly will shew it self in a bright colour it must of necessity not reflect at all or but very feebly if it penetrates into a body of much humidity or loses it self in the pores of it and that little which comes so weakly from it must consequently appear of a duskie die And these two being all the causes of the great variety of colours we see in bodies according to the quality of the body in which the real colour appears it may easily be determined from which of these it proceeds and then by the colour you may judge of the composition and mixture of the rare and dense parts which by reflecting light begets it In fine out of all we have hitherto said in this Chapter we may conclude the Primary intent of our so long discourse which is That the Senses of Living Creatures and the Sensible Qualities in Bodies are made by the Mixtion of Rarity and Density as well as the Natural Qualities we spoke of in their place For it cannot be denied but that heat and cold and the other couples or pairs which beat upon our Touch are the very same as we see in other bodies the qualities which move our Taste and Smel are manifestly a kin and joyn'd with them Light we have concluded to be Fire and of Motion which affects our ear ther 's no dispute so that it is evident how all sensible quaqualities are as truly bodies as those other Qualities which we call natural To this we may add that the Properties of these sensible qualities are such as proceed evidently from Rarity and Density For to omit those which our Touch takes notice of as too plain to be question'd Physitians judg and determine the natural qualities of meat and medicines and simples by their Tastes and Smels By those qualities they find out powers in them to do material operations and such as our instruments of cutting filling brushing and the like do to ruder and grosser bodies all which vertues being in these instruments by the different tempers of Rarity and Density is a convincing argument that it must be the same causes which produce effects of the same kind in their smel and tastes And and as for light 't is known how corporeally it works upon our eyes Again if we look particularly into the composition of the organs of our Senses we shall meet with nothing but such qualities as we find in the composition of all other natural bodies If we search into our Eye we shall discover in it nothing but diaphanety softness divers colours and consistencies which all Anatomists to explicate parallel in other bodies the like is of our Tongue our Nostrils and our Ears As for our Touch that is so material a sense and so diffused over the whole body as we can have no difficulty about it Seeing then that all the qualities we can discover in the organs of our Senses are made by the various minglings of Rarity with Density how can we doubt but that the active powers over these patients must be of the same nature and kind Again seeing that examples above brought convince That the objects of one sense may be known by another who can doubt of a community among them if not of degree at least of the whole kind as we see that the Touch is the groundwork of all the rest and consequently that being evidently corporeal and consisting in a temper of Rarity Density why should we make difficulty in allowing the like of the rest Besides let us compose of Rarity and Density such tempers as we find in our Senses and let us again compose of Rarity and Density such actors as we have determined the qualities we call sensible to be and will it not manifesty follow that these two applyed to one another must produce such effects as we affirm our Senses have that is to pass the outward objects by different degrees to an inward receiver Again let us cast our eyes upon the natural resolution of bodies and how they move us and we shall therby discover both what the Senses are and why they are just so many and that they cannot be more For an outward body may move us either in its own bulk or quantity or as it works upon another The first is done by the Touch the second by the Ear when a body moving the air makes us take notice of his motion Now in resolution there are three active parts proceeding from a body which have power to move us the fiery part which you sees works upon your eyes by the virtue of light the airy part which we know moves our nostrils by being suck'd in with the air And lastly the salt which dissolves in water and so moves our watry sense which is our taste And these being all the active parts that shew themselvs in the resolution of a body how can we imagine there should be any more senses to be wrought upon For what the stable body shews of it self will be reduced to the touch what as it moves to hearing what the resolutions of it according to the natures of the resolved atomes that fly abroad will concern the other three senses as we have declared And more ways of working or of active parts we cannot conceive to spring out of the nature of a body Finally if we cast our eyes upon the intention of nature to what purpose are our Senses but to bring us into knowledge of the natures of the substances we converse withall Surely to effect this there cannot be invented a better or more reasonable expedient then to bring to our judgment seat the likenesses or extracts of those substances in so delicate a model that they may not be offensive or cumbersom like so many patterns presented to us to know by them what the whole piece is For all similitude is a communication between two things in that quality wherin their likeness consists And therfore we cannot doubt but that nature hath given us by the means whe have explicated an essay to all things in the world that fall under our commerce wherby we judge whether they be profitable or nocive to us and yet in so delicate and subtile a quantity as may in no way be offensive to us whiles we take our measures to attract what is good and avoid what is noxious CHAP. XXXII Of Sensation or the motion wherby Sense is properly exercised OUt of the considerations which we have delivered in these last Chapters the Reader may gather the unreasonablenesse of vulgar Philosophers who to explicate life and sense are
Retentive and the Expulsive faculties to be discoursed of wherof one kind is manifestly belonging to the voluntary motion which we have declared namely that retension and that expulsion which we ordinarily make of the gross excrements either of meat or drink or of other humours either from our head or stomach or Lungs for it is manifestly done partly by taking in of wind and partly by compressing of some parts and opening of others as Galen shews in his curious book de usu partium Another kind of Retention and Expulsion in which we have no sense when it is made or if we have it is of a thing done in us without our will though peradventure we may voluntarily advance it is made by the swelling of fibers in certain parts through the confluence of humours to them as in our stomach it happens by the drink and the juice of the meat that is in it which swelling closes up the passages by which the contained substance should go out as the moistening of the strings and mouth of a purse almost shuts it till in some for example the stomach after a meal the humour being attenuated by little and little gets out subtilely and so leaving less weight in the stomach the bag which weighs down lower than the nearer Orifice at which the digested meat issues rises a little And this rising of it is also further'd by the wrinkling up and shortning of the upper part of the stomach which still returns into its natural corrugation as the masse of liquid meat leavs soaking it which it doth by degrees still as more and more goes out and so what remains fills less place and reaches not so high in the stomach And thus at length the residue and thicker substance of the meat after the thinnest is got out in steam and the midling part is boil'd over in liquor comes to presse and gravitate wholly upon the Orifice of the stomach which being then help'd by the figure and lying of the rest of the stomach and its strings and mouth relaxing by having the juice which swell'd them squeez'd out of them it opens it self and gives way to that which lay so heavy upon it to tumble out In others for example in a woman with child the enclosed substance retain'd first by such a course of nature as we have set down breaks it self a passage by force and opens the orifice at which it is to go out by violence when all circumstances are ripe according to natures institution But yet there is the expulsion made by Physick that requires a little declaration 'T is of five kinds Vomiting Purging by Stool by Urine Sweating and Salivation every one of which seems to consist of two parts namely the Disposition of the Thing to be purged and the Motion of the Nervs or Fibers for the expulsion As for example when the Physician gives a Purge it works two things one is to make some certain humour more liquid and purgeable than the rest the other is to make the stomach or belly suck or vent this humour For the first the property of the Purge must be to precipitate that humour out of the rest of the blood or if it be thick to dissolve it that it may run easily For the second it ordinarily heats the stomach and by that means causes it to suck out of the veins and so to draw from all parts of the body Besides this it ordinarily fills the belly with wind which occasions those gripings men feel when they take physick and is cause of the guts discharging those humours which otherwise they would retain The like of this happens in Salivation for the humours are by the same means brought to the stomach and thence sublimed up to be spitten out as we see in those who taking Mercury into their body either in substance or in smoak or by application do vent cold humours from any part the Mercury rising from all the body up to the mouth of the patient as to the helm of a sublimatory and the like some say of Tobacco As for Vomiting it is in a manner wholly the operation of the fibers provoked by the feelling of some inconvenient body which makes the stomack wrinkle it self and work and strive to cast out what offends it Sweating seems to be caus'd by the heating of some nitrous body in the stomach which being of subtile parts is by heat dispersed from the middle to the circumference and carries with it light humours which turn into water as they come out into the air And thus you see in general and as much as concerns us to declare what the Natural Faculties are and this according to Galen's own mind who affirms that these faculties follow the complexion or temper of parts of a mans body Having explicated how Voluntary motion proceeds from the brain our next work ought to be to examine what it is that such an object as we brought by means of the senses into the brain from without contributes to make the brain apply it self to work such voluntary motion To which purpose we will go a step or two back to meet the object at its entrance into the sense and from thence accompany it in all its journey and motions onwards The object which strikes at the senses dore and getting in mingles it self with the spirits it finds there is either conform and agreeable to the nature and temper of those spirits or it is not that is to say in short it is either pleasing or displeasing to the living creature Or it may be a third kind which being neither of these we may term indifferent In which sort soever the obect affects the sense the spirits carry it immediately to the brain unless some distemper or strong thought or other accident hinder them Now if the object be of the third kind that is be indifferent as soon as it has strucken the brain it rebounds to the circle of the memory and there being speedily join'd to others of its own nature it finds them annex'd to some pleasing or displeasing thing or it doth not if not in beasts it serves to little use and in men it remains there till it be call'd for but if either in its own nature it be pleasing or displeasing or afterwards in the memory it be-became join'd to some pleasing or annoying fellowship presently the heart is sensible of it For the heart being join'd to the brain by straight and large nervs full of strong spirits which ascend from the heart 't is impossible but that it must have some communication with those motions which pass in the brain upon which the heart or rather the spirits about it is either dilated or compressed And these motions may be either totally of one kind or moderated and allay'd by the mixture of its contrary if of the former sort one of them we call Joy the other Grief which continue about the heart and peradventure oppress it if they be
peradventure very seldom upon doing something out of which the desired effect follows as it cannot choose but fall out now and then though chance only govern their actions and when their action proves succesful it leaves such an impression in the memory that whenever the like occasion occurrs that animal will follow the same method for the same specieses do come together from the memory into the fantasie But the many attempts that miscarry and the ineffectual motions which straights do cast beasts upon are never observ'd nor are there any stories recorded of them no more than in the Temple of Neptune were kept upon the registers the relations of those unfortunate wretches who making vows to that God in their distress were nevertheless drowned Thus peradventure when the Fox sees his labour in chasing the hens to be to no purpose and that by his pursute of them he drives them further out of his reach he laies himself down to rest with a watchful eye and perceiving those silly animals to grow bolder and bolder by their not seeing him stir he continues his lying still till some one of them comes within his reach and then on a sudden he springs up and catches her Or peradventure some poultry might have strai'd within his reach whiles he was asleep and have then wakened him with some noise they made and so he happned to seise upon one of them without either design or pains taking before-hand By such degrees he might chance to catch one the first time and they being setled in his memory together with the effect it hap'ned that another time when hunger pressed him and sent up to his brain like spirits to those which ascended thither whiles he say watching the hens these spirits brought the other from his memory into the fantasie in such sort as we have shew'd in the last Chapter and so drove him to the same course till by frequent repetition it became ordinary and familiar with him And then they that look only upon the performance of the artifice are apt to infer discourse and a design of reason out of the orderly conduct of it But how can we concieve the Fox hath judgment to know when the hen is come within his leap and accordingly offers not at her till then unless we resort to some other principles than what is yet declared The answer to this objection I think will not be hard to find for if the motion which the presence of the object makes in the heart be proportion'd out by nature as there is no doubt but it is it will not be so great and powerful as to make the Fox leap at it till it be arrived so near him that he by his nimbleness can reach it and so without any aim further than by the meer flux of his passion conveniently rais'd he doth the feat But if his passion be too violent it makes him miss his aim as we may frequently observe both in men and beasts and particularly when fear presses either of them to leap over a ditch which being too broad he lights in the midst of it The same watchfulness and desire to have the poulen which then sit upon a tree out of his reach makes him fix his eyes on them when they are at roost and at length either the brightness and sparkilng of them dazles the birds and makes them come down to him as flies do in the night about the flame of a candle or as fishes do to a light in a boats head or else they are afraid and their fear increasing their spirits return to the heart which therby is oppressed and their outward parts are bereav'd of strength and motion from whence it follows necessarily that their footing looses their hold fast and they tumble down half dead with fear which happens also frequently to cats when they look wishly upon little birds that sit quietly Or peradventure their fear makes them giddy as when some man looking down a precipice from a dangerous standing falls by the turning of his brain though nothing be behind him to thrust him forwards Or it may be some steam comes from the Fox which draws such creatures to him as 't is reported that a great and very poisonous Toad will do a Weasel who will run about the Toad a great while and still make his circle lesser and lesser till at length he peâ—ishes in the center were his foe sits still and draws him to him Which he doth in such sort as animated Mercury will draw leaf-gold duly prepared or as the Load stone attracts Iron and yet 't is apparent the Weasel comes not with his good will but that there are some powerful chains steaming from the body of the Toad which pluck him thither against his liking for by his motions and runing he will express the greatest fear that can be The method which Foxes practise to rid themselvs of their fleas if it be true is obvious enough for them to fall upon for in Summer their sleas together with their thick fur'd coat cannot choose but cause an exceeding great itching and heat in their bodies which will readily invite them to go into the water to cool themselves As the Merchants at the Isles of Zante and of Cephalonia told me when I was there it was the custom of our English Dogs who were habituated to a colder clime to run into the Sea in the heat of Summer and lie there most part of the day with only their noses out of the water that they might draw breath and would sleep there with their heads laid upon some stone which raised them up whiles their bodies were cover'd with the Sea and those Dogs which did not thus would in one Summer usually be kill'd with heat and Fleas Now when the Fox feels the ease that the coolness of the water affords that part of him which sits in it he goes further and further yet would not put himself to swim which is a labour and would heat him and therfore he avoids it so that whiles he thus cools himself in some shady place for 't is natural to him in such an occasion to resort to the cool shade rather than to I le in the Son and in such there being for the most part some boughs hanging over the water it happens naturally enough that he takes some of the lowest in his mouth to support him and save hi m the labour of swiming whiles he lies at his ease soaking and cooling himself in the River By which means it comes to pass that the Fleas finding no part of him free from water creep up the bough to rescue themselvs from drowning and so when he is cool'd enough he goes away and leaves them there In all which finding a benefit and satisfaction whenever the like occasion brings those species from his memory into his fantasy he betakes himself to the same course and therin finding his remedy at length it grows familiar to him In like manner
is in them nothing else but each of them to be white and two quantities to be half and whole is in theÌ„ nothing else but each quantity to be just what it is But a respect in its own nature is a kind of tye co mparison tending or order of one of those things to another and is no where to be found in its formal subsistence but in the apprehensiou of man therfore it cannot be described by any similitude nor be expressed by any means but like Being by the sound of a word which we are agreed on to stir up in such a notion For in the things it is not such as our notion of it is which notion is that we use to express by Prepositions and Conjunctions and which Aristotle Logicians express in common by the word 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 or ad therfore there is nothing out of us to paint it by as I could do white or square or round or the like because these have a beings in the things that are white or square c. consequently they may be expressed by others of the like nature but the likeness that one white hath to another or the respect that either of them hath to mans imagination is only in man who by comparing them gives birth to the nature and being of respect Out of this discourse we may collect two Singularities of Man which 't will much import us to take particular notice of One is that Being or a thing the formal notion of which is merely Being is the proper affection of man For every particular thing is in him by being as I may say grafted upon the stock of Existence or being And accordingly we see that whatever we speak of we say is something and whatever we conceive we give the nature of a thing as when we have said the wall is white we frame whiteness as a thing so immediately before speaking of Respect we took respect as it were a thing and enquired where it is so that 't is evident all the negotiation of our understanding trades in all that is apprehended by it as if they were things The other Singularity we may observe in man is that he is a coÌ„paring power for all his particular knowledges are nothing else but respectsa nd comparisons between particular things as for example for a manto know heat or cold c. is to know what effects fire or water c. can work upon such or such bodies Out of the first of these proprieties it follows that what effects a man or makes impression upon his understanding doth not therby lose its own peculiar nature nor is modified to the recipient the contrary of which we see happens perpepetually in bodies Observe the sustenance we take which that it may become part of our body is first changed into a substance like our body and ceases being what it was When water or any liquid body is receiv'd into a vessel it loses its own figure puts on the figure of the vessel it is in If heat enters into a body that is already hot that heat becomes therby more heat if into a cold body it is converted into warmth And in like manner all other corporeal things are accommodated to the quallities of the recipient and in it they lose their own proper terms and cosistences but what comes into the understanding of a man is so received by or joyn'd to him that it still retains its own proper limitations and particular nature notwithstanding its assumption to him For Being is joyn'd to every thing there since as we have said 't is by Being that any thing comes thither consequently this stock of Being makes every graft that is inoculated into it Be what of its own nature it is For Being joyn'd to another motion doth not change that notion but makes it be what it was befoâ—e since if it should be changed Being were not added to it as for example add Being to the notion of knife and it makes a knife or that notion to Be a knife and if after the addition it doth not remain a knife it was not Being that was added to a knife Out of the later of the singularities proper to man it follows that a multitude of things may beunited in him without suffering any confusion among themselvs but every one of them will remain with its proprieties and distinct limitations For so of necessity it must be when that which unites them to him is the comparing them to something besides themselvs which work could not be perform'd unless what is to be compared retain exactly its own nature wherby the comparison may be made no more than one can weigh two quantities one against another unless he keep asunder what is in each seal and keep all other weights from mingling with them And accordingly we see that we cannot compare black to white or a Horse to an Oxe unless we take together the properties by which black differs from white or an oxe from an horse and consequently they must remain unmingled and without confusion precisely what in themselvs they are and be indifferent in the sight of the comparer But indeed if we look well into the matter we shall find that setting aside the notion of Existence or Being all our other notions are nothing else but comparisons and respects and that by the mediation of respects the natures of all things are in us and by the varying of them we multiply our Notions Which in their first division that reduces their several kinds into general heads increase into the Ten famous Tribes that Logicians call Predicaments and they comprehend under them all the particular notions that man hath or can have according to the course of knowledge in this life Of which Predicaments the seven last are so manifestly respective that all men acknowledg them to be so Substance we have already shew'd to have a respect to Being Quantity we proved in the first Chapter of the former Treatise of the Nature and Operation of Bodies to consist in a respect to Parts Quality is divided into four branches wherof Power is clearly a respect to that over which it hath power or from which it may suffer Habite is a respect to the substance wherin it is as being the property by which it is well or ill conveniently or inconveniently affected in regard of its own nature as you may observe in health or sickness or the like The Passible Qualities are those we have explicated in discoursing of the Elements and of Mixts and whose natures we have there shew'd consist in respects of acting or suffering Figure or shape which is the last branch of the division of the Predicament of Quality is nothing else but a certain disposition of one part of a body to another And so you see how all the Ten Predicaments consist purely in diversity of Respects by consequence all our conceits and notions excepting that
to express our notions the one common to all men the other proper to Scholars 7. Great errours arise by wresting words from their common meaning to express a more particular or studied notion 1. We must know the vulgar and common notion of Quantity that we may understand the nature of it 2. Extension or Divisibility is the common notion of Quantity 3 Parts of Quantity are not actually in their whole 4 If parts were actually in their whole Quantity would be composed of indivisibles 5. Quantity cannot be composed of indivisibles 6 An objection to prove that parts are actually in Quantity with a declaration of the mistake from whence it proceed 7 The solution of the former objection and that Sense and not discern whether one part be distinguish'd from another or no. Chap 〈◊〉 8. 2. 3. 8. An enumeration of the several specieses of Quantity which confirms that the essente of it is divisibilitie 1 What is meant by Rarity and Densitie 2. 'T is evident that some bodies are rare and others dense though obscure how they are such 3. A brief enumeration of the several properties belonging to rare and dense bodies 4. The opinion of those Philosophers declared who put Rarity to consist in an actual division of a Body into little parts 5. The former opinion rejected and the ground of their errour discover'd 6 The opinion of those Philosophers related who put Rarity to consist in the mixtion of Vacuity among bodies The opinion of Vacuities refuted Dialog 1. del Movim pag. 18. Archimed promot 8. Rarity and Density consist in the severall proportions which Quantity hath to its Substance 9. All must admit in Physical bodies a Metaphysical composition 1. The notions of density and rarity have a latitude capable of infinite variety 2. How mâ—istness and dryness are begotten in dense bodies 3. How moistness and drieess are begotten in rare bodies 4. Heat is a propertie of rare bodies and cold of dense ones 5. Of the two dense bodies the less dense is more cold but of the two rare ones the less rare is less hot 6 The extreme dense body is more dry then the extreme rare one 7. There are but four simplebodies and these are rightly named Elements 8 The Author doth not determine whether every Element comprehends under its name one only lower species or many nor whether any of them be found pure 1. The first operation of the Elements is division out of which resulreth local motion What place is both notionally and really 3. Locall motion is that division whereby a body changes its place 4. The nature of quantity of it self is sufficient to unite a body to its place 5. All operations amongst bodies are either local motion or such as follow out of local motion 6. Earth compared to water in activity S. 6. 7. The manner whereby fire gets into fewel proves that it exceeds earth in activity 8. The same is proved by the manner wherby fire comes out of fewel and works upon other bodies 1. In what sense the Author rejects Qualities In what sense the Author admits of qualities 3. Five arguments proposed to prove that light iâ— not a body 4. The two first reasons to prove light a body are the resemblance it hath with fire and because if it were a quality it would always produce an equall to it self 5. The third reason because if we imagine to our selves the substance of fire to be rarified it will have the sâ—me appearances which light hath 6. The fourth reason from the manner of the generation and corruption of light whcih agrees with fire 7. The fifth reason because such properties belong to light as agree only to bodies 1. That all light is hot and apt to heat 2. The reason why our bodies for the most part do not feel the heat of pure light 3. The experience of burning glasses and of soultry gloomy weather prove light to be fire 4. Philosophers ought not to judge of things by the rules of vulgar people 5. The different names of light and fire proceed from different notions of the same substance 6. The reason why many times fire and head are deprived of light 7. What becoms of the body of light when it dies 8. An experiment of some who petend that light may be precipitated into powder 9. The Authors opinion concerning lamps pretended to have been found in Tombes with inconsumptible lights 1. Light is not really in every part of the room it enlightens nor fills entirely any sensible part of it though it seem to us to do so 2. The least sensible point of a diaphanous body hath room sufficient to contain both air and light together with a multitude of beams issuing from several lights without penetrating one another * Willibrord Snell 3. That light doth not enlighten any room in an instant and that the great celerity of its motion doth make it imperceptible to our senses 4. The reason why the motion of light is not discern'd coming towards us and that there is some reall tardity in it 5. The Planets are not certainly ever in that place where they appear to be 6. The reason why light being a body doth not by its motion shatter other bodies into pieces 7. The reason why the body of light is never perceiv'd to be fanned by the wind The reasons for and against lights being a body compared together A summary repetition of the reasons which prove that light is fire 1. No local motion can be perform'd without succession 2. Time is the common measure of all sucessione 3 What velocity is and that it cannot be infinite 4. No force so little that is not able to move the greatest weight imaginable 5. The chief principle of Mechanicks deduced out of the former discourse 6. No moveable can passe from rest to any determinate degree of velocity or from a lesser degree to a greater without passing through all the intermediate degrees which are below the obtained degree 7. The conditions which help to motion in the movable are three in the medium one Dialog 1. of Motion 8. No body hath any intrinsecal vertue to move it self towards any determinate part of the Universe 9. The encrease of motion is always made in the proportion of the odd numbers 11. Certain problems resolved concerning the proportion of some moving agents compared to their effects 12. When a moveable comes to rest the motion decreases according to the rules of encrease 1. Those motions are call'd natural which have constant causes and those violent which are contrary to them 2. The first and most general operation of the Sun is the making and raising of atomes 3. The light rebounding from the earth with atomes causes two streams in the air the one ascending the other descending and both of them in a perpendicular line 4. A dense body placed in the air between the ascending and descending streams must needs descend 5. A more particular explication of all the former doctrine
touching Gravity 6. Gravity and levity do not signifie an intrinsecal inclination to such a motion in the bodies themselvs which are term'd heavy and light 7. The more dense a body is the more swiftly it descends 8. The velocity of bodies descending doth not encrease in proportion to the difference that may be between their several densities 9. More or less gravity produces a swister or a slower descending a heavy body Aristotles argument to disprove motion in 〈◊〉 is made good 10. The reason why at the inferior quarter of a circle a body descends faster by the arch of that quarter then by the chord of it 1. The first objection answered why a hollow body descends flower then a solid one 2 The second objection answer'd and the reasons shown why atoms continually overtake the descending dense body 3. A curious queston left undecided 4. The fourth objection answer'd Why the descent of the same heavy bodies is equal in so great inequality of the atoms which cause it 5. The reason why the shelter of a thick-body doth not hinder the descent of that which is under it 6. The reason why some bodies sink others swims 7. The fifth objection answer'd concerning the descending of heavy bodies in streams 8. The sixth objection answered and that all heavy Elements do weigh in their own Spheres 9 The seventh objection answer'd and the reason why we do not feel the course of the air and atoms that beat continually upon us 10. How in the some body gravity may be greater than density and density than gravity though they be the same thing 11. The opinion of gravities being an intrinsecal inclination of a body to the centre refuted by reason â—2 The same opinion refuted by several experiences 1. The State of the question touching the cause of violent motion 2 That the medium is the only cause which continues violent motion 3. A further explication of the former Doctrine 4. That the air has strength enough to continue violent motion in a moveable Dial. 1. of motion pag. 98. 5. An answer to the first objection that air is not apt to conserve motion And how violent motion comes to cease 6. An answer to the second objection that the air has no power over heavy bodies 7. An answer to the third objection that an arrow should fly faster broadways than long ways 1. That reflection is a kind of violent motion 2. Reflection is made at equal angles 3. The causes and properties of Undulation 4. Refraction at the entrance into the reflectent body is towà rds the perpendicular at the going out is from it when the second superficies is parallel to the first 6. An answer to the arguments brought in favovr of Monsir des Cartes his opinion 7. The true cause of refraction of light both at its entrance and at its going out from the reflecting body 8. A general rule to know the nature of reflections and refractions in all sorts of surfaces 9. A body of greater parts and greater pores makes a greater refraction than one of lesser parts and lesser pores 10. A confirmation of the former doctrine out of the nature of bodies that refract light 1. The connexion of this Chapter with the rest and the Authors intent in it 2. That there is a least size of bodies And that this least size is found in fire 3. The first conjunction of parts is in bodies of least size and it is made by the force of Quantity 4. The second sort of conjunction â—s compactedness in simple Elements and it proceeds from Density 5. The third conjunction is of parts of different Elements and it proceeds from quantity and density together 6. The reason why liquid bodies easily joyn together and dry ones difficultly 7. That no two hard bodies can touch one another immediately 8. How mixed bodies are framed in general 9. The cause of the several degrees of solidity in mixed bodies 10. The rule whereto are reduced all the several combinations of Elements in compounding of mixed bodies 11. Earth and water are the Basis of all permanent mixed bodies 12. What kind of bodies those are where water is the Basis and earth the pedominant element over the other two 13. Of these bodies where water bing the B sis air is the predominant Element 14. What kind of bodies result where water is the Basis and fire the predominant Element 15. Of those bodies where water is in excess it alone being both the Basis and the predominant Element 16. Of those bodies were Earth alone is the Basis and also the predominant in excess over the other three Elements 17. Of those bodies where Earth is the basis and Water the predominant Element over the other two 18. Of those bodies where earth being the basis air is the predominant 19. Of those bodies where earth being the basis fire is the predominant 20. All the Second Qualities of mixed bodies arise from several combinations of the First Qualities and are at last resolv'd into several degrees of rarity and density 21. That in the Planets and Stars there is a like variety of mixed bodies caused by light as here upon Earth 22. In what manner the Elements work upon one another in the position of mixed bodies and in particular fire is the most active 23. A particular declaration touching the generation of Metals 1. Why some bodies are brittle and others tough or apt to withstand outward violence the first instrument to dissolve mixed bodies 2. How outward violence work upon the most compacted bodies 3. The several effects of fiâ—e the second and chiefest instrument to dissolve compounded bodies 4. The reason why some bodies are not dissolv'd by fire 5. The reason why fire melts gold but cannot consume it 6. Why Lead is easily consumed and calcined by fire 7. Why and how some bodies are divided by fire into spirits waters oyls salts and earth what those parts are 〈◊〉 How water the third instrument to dissolve bodies dissolves Calx into Salt and so into Terra damnata 9. How water mingled with salt becomes almost powerfull Agent to dissolve other bodies 20. How putrefaction is caused 1. What is the Sphere of Activity in corporeal Agents 2. The reason why no body can work in distance 3. An objection answer'd against the manner of explicating the former Axiome 4 Of reaction and first in pure local motion that each Agent must suffer in acting and act in suffering 5. The former doctrine applyed to other local motions design'd by particular names And that Suisseths argument is of no force against this way of doctrine 6. Why some notions admit of intension and remission and others not 7. That in every part of our habitable world all the four Elements are found pure in smal atoms but not in any great bulk 1. The Authors intent in this and the following chapters Mr. Thomas White 2. That bodies may be rarified both by outward and inward heat and how this is perform'd 3.
Of the great effects of Rarefaction 4. The first manner of condensation by heat 5. The second manner of condensation by cold 3. That Ice is not water rarifiâ—d but condensed 7. How wind snow and hail are made and wind by rain allayed 8. How parts of the same or divers bodies are joyned more strongly together by condensation 9. Vacuities cannot be the reason why water impregnated to the full with one kind of salt will notwithstanding receive more of another 10. The true reason of the former effect 11. The reason why bodies of the same nature jâ—yn more easily together then others 1. What attraction is and from whence it proceeds 1. The true sense of the Maxime that Nature abhors from vacuity 3. The true rea son of attraction 4. Water may be brought by the force of attraction to what height soever 5. The doctrine touching the attraction of water in Syphons 6. That the Syphon doth not prove water to weigh in its own orb 7. Concerning attraction caused by fire 8. Concerning attraction made by virtue of hot bodies amulets c. 9. The natural reason given for divers operations esteemed by some to be magical 1. What is Filtration and how it is effected 2. What causes the water in filtration to ascend 3. Why the filter will not drop unless the label hang lower then the water 4. Of the motion of Râ—stitution and why some bodies stand bent others not 5. Why some bo dies return only in part to their natural figure others entirely 6. Concerning the nature of those bodies which shrink and stretch 7. How great wonderful effects proceed from smal plain and simple principles 8. Concerning Electrical at action and the causes of it 6. Cabeus his opinion reâ—uted concerning the cause of Electrical motions 1. The extreme heat of the Sun under the Zodiack draws a stream of air from each pole into the Torrid Zone * Chap. 18. Sect. 7. 2. The Atoms of these two streams coming together are apt to incorporate with one another 3. By the meeting and mingling together of these streams at the Equator divers rivolets of Atoms of each Pole are continuated from one Pole to the other 4. Of these Atoms incorporated with some fit matter in the bowels of the earth is made a stone 5. This stone works by emanations joyned with agreeing streams that meet them in the air and in fine it is a Loadstone 6 A methode for making experiences on any subject 7. The Loadstones generation by atoms flowing from both Poles is confirmd by experiments observ'd in the stone it self 8. Experiments to prove that the Loadstone works by emanations meeting with agreeing streames 1. The operations of the loadstone are wrought by bodies and not by qualities 2. Objections against the former position answer'd 3. The Loadstone is imbued with his virtue from another body 4 The virtue of the Loadstone is a double and not one simple virtue 5. The virtue of the Loadstone works more strongly in the poles of it then in any other part 6. The loadstone sends forth its emanations spherically Which are of two kindâ— and each kind is strongest in that Hemisphere through whose polary parts they issue out 7. Putting two loadstones within the sphere of one another every part of one loadstone doth not agree wâ—th every part of the other loadstone 8. Concetning the declination and other respects of a needle towards the loadstone it touches 8. The virtue of the Loadstone goes from end to end in lines almost parallel to the Axis 10. The virtue of the Loadstone is not perfectly spherical though the stone be such 11. The intention of nature in all the operations of the loadstone is to make an union betwixt the attractive and attracted bodies 12. The main globe of the earth is not a Loadstone 13. The loadstone is generated in all parts or Climâ—t's of the earth 14. The conformity betwixt the two motions of magnetick things and of heavy things 1. Which is the North and which the South Pole of a Loadstone 2. Whether any bodies besides magnetick ones be attractive 3. Whether an iron placed perpendicularly towards the earth gets a magnetical virtue of pointing towards the north or towards the south in that end that lies downwards 4. Why loadstones affect iron better than one another 5. Gilberts reason refuted touching a cap'd Loadstone that takes up more iron then one not cap'd and an iron impregnated that in some case draws more strongly then the stone it self Galileus his opinion touching the former effects refuted 7. The Authors solution to the former questions 8. The reason why in the former case a lesser Loadstones draws the interjacent iron from the greater 9. Why the variation of a touched needle from the North is greater the nearer you go to the Pole 10. Whether in the same part of the world a touched needle may it one time vary more fâ—om the North and at another time less 11. The whâ—le doctrine of the loâ—dstone sum'd up in short 1. The connexion of the following Chapters with the precedent ones 2. Concerning several compositions of mixed bodies 3. Two sorts of Living Creatures 4. An engine to express the first sort of living creatures 5. Another Engine by which may be expressed the second sort of living creatures 4. The two former engines and some other comparisons applied to express the two several sorts of living creatures 7. How plants are framed 8. How Sensitive Creatures are formed 1. The opinion that the seed contains formally every part of the parent 2. The former opinion rejected 3. The Authours opinion of this question 4. Their opinion refuted who hold that every thing contains formally all things 5. The Authors opinion concerning the generation of Animals declared and confirm'd That one substance is changed into another 7. Concerning the hatching of Chickens and the generation of the other Animals 8. From whence it happens that the deficiences or excresences of the parents body are often seen in their children 9. The difference between the Authors opinion anâ—â—he former 〈◊〉 10 That the heart is imbued with the general specifike vertues of the whole body wherby is confirm'd the doctrine of the two former Paragraphes 11 That the heart is the first part generated in a living creatures 1. That the figure of an Animal is produced by ordinary second causes as well as any other corporeal effect 2. That the several figures of bodies proceed from a defect in one of three dimensions caused by the circumference of accidental causes 3. The former doctrine is confirmd by several instances 4. The same doctrine applyed to plants 4. The same doctrine declared in leaves of trees 16. The same applied to the bodies of Animals 7. In what sense the Author admits of vis formatrix 1. From whence proceeds the primary motion growth in Plants 2. Mr. des Cartes his opinion touching the motion of the heart 3. The former opinion rejected 4. The Authors opinion
proportion over air and water And this I conceive produces those substāces which we may term co-agulated juyces and which the Latines call succi concreti whos 's first origine seems to have been liquours that have been afterwards dried by the force either of heat or cold Of this nature are all kind of Salts Niters Sulfurs and divers sorts of Bitumens All which easily bewray the relicks and effects of fire left in them some more some less according to their degrees And thus we have in general deduced from their causes the complexions of those bodies whereof the bulk of the world subjected to our use consists and which serve for the production and nourishment of living creatures both animal and vegetable Not so exactly I confess nor so particularly as the matter in it self or as a Treatise confined to that subject would require yet sufficiently for our intent In the performance whereof if more accurate searchers of nature shall find that we have peradventure been mistaken in the minute delivering of some particular bodies complexion their very correction I dare boldly say will justifie our principal scope which is to shew that all the great variety we see among bodies arises out of the commixion of the First Qualities and of the Elements for they will not be able to correct us upon any other grounds then those we have laid As may easily be perceiv'd if we cast a summary view upon the qualities of compounded bodies All which we shall find to spring out of rarity and density and to savour of their origine for the most manifest qualities of bodies may be reduced to certain pairs opposite to one another As namely some are liquid and flowing others are consistent some are soft others hard some are fatty viscuous and smooth others lean gritty and rough some gross others subtile some tough others brittle and the like Of which the liquid the soft the fat and the viscuous are so manifestly derived from rarity that we need not take any further pains to trace out their origine and the like is of their contraries from the contrary cause to wit of those bodies that are consistent hard lean and gritty all which evidently spring from density As for smoothness we have already shew'd how that proceeds from an airy or oily nature and by consequence from a certain degree of rarity And therefore roughness the contrary of it must proceed from a proportionable degree of density Toughness is also a kind of ductility which we have reduced to watriness that is to another degree of rarity and consequently brittleness must arise from the contrary degree of density Lastly grossness and subtilness consist in a difficulty or facility to be divided into small parts which appears to be nothing else but a certain determination of rarity and density And thus we see how the several complexions of bodies are reduced to the four Elements that compound them and the qualities of those bodies to the two primary differences of quantitative things by which the elements are diversified And out of this discourse it will be evident that these complexions and qualities though in diverse degrees must of necessity be found wherever there is any variation in bodies For seeing there can be no variation in bodies but by rarity and density and that the pure degrees of rarity and density make heat cold moisture and driness and in a word the four Elements 't is evident that wherever there is variety of bodies there must be the four Elements though peradventure far unlike these miked bodies which we call Elements And again because these Elements cannot consist without motion and by motion they of necessity produce Mixed bodies and forge out those Qualities which we come from explicating it must by like necessity follow that wherever there is any variety of active and passive bodies there mixed bodies likewise must reside of the same kinds and be indued with qualities of the like natures as those we have treated of though peradventure such as are in other places of the world remote from us may be in a degree far different from ours Since then it cannot be denied but that there must be notable variety of active and passive bodies wherever there is light neither can it be denied but that in all those Great Bodies from which light is reflected to us there must be a like variety of complexions and qualities and of bodies temper'd by them as we find here in the Orb we live in Which Systeme how different it is from that which Aristotle and the most of the School have deliver'd us as well in the evidencies of the proofs for its being so as in the position and model of it I leave to the prudent Readers to consider and judge Out of what has been already said 't is not hard to discover in what manner the composition of bodies is made In effecting which the main hinge wheron that motion depends is fire or heat as it likewise is in all other motions whatever Now because the composition of a mixed body proceeds from the action of one simple body or element upon the others it will not be amiss to declare by some example how this work passes for that purpose let us examine how fire or heat works upon his fellows By what we have formerly deliver'd 't is clear that fire streaming out from its centre and diffusing it self abroad so as to fill the circumference of a larger circle it must needs follow that the beams of it are most condens'd and compacted together near the centre and the further they stream from the centre the more thin and rarified they must grow yet this is with such moderation as we cannot any where discern that one beam doth not touch another and therfore the distances must be very smal Now let us suppose that fire happens to be in a viscuous and tenacious body and then consider what will happen in this case of one side the fire spreads it self abroad on the other side the parts of the tenacious body being moist as I have formerly determin'd their edges on all hands will stick fast to the dry beams of the fire that pass between them Then they stretching wider and wider from one another must needs draw with them the parts of that tenacious body which stick to them and stretch them into a greater widness or largness then they enjoy'd before from whence it follows that seeing there is no other body near therabouts but they two either there must be a vacuity left or else the tenacious body must hold and fill a greater space then it did before and consequently be more rare Contrariwise of any of the other elements be stronger then fire the denser Elements break off from their continu'd stream the little parts of fire which were gotten into their greater parts and sticking on all sides about them so enclose them that they have no more semblance of fire and