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
by its Equator And consequently it is impossible that its sphere of activity should be perfectly spherical Nor doth Cabeus his experience move us to conceive the loadstone hath a greater strength to retain an iron laid upon it by its Equator then by its Poles for to justifie his assertion he should have tried it in an iron wire that were so short as the poles could not have any notable operation upon the ends of it since otherwise the force of retaining it wil be attributed to the Poles according to what we have above deliver'd and not to the Equator The eighth position is that The intention of nature in all the operations of the Loadstone is to make an union betwixt the attractive and the atracted â—bodies Which is evident out of the sticking of them together as also out of the violence wherwith iron comes to a Loadstone which when it is drawn by a powerful one is so great that through the force of the blow hitting the stone it will rebound back and then fall again to the stone And in like manner a needle upon a pin if a Loadstone be set near it turns with so great a force towards the pole of the stone that it goes beyond it and coming back again the celerity wherwith it moves maketh it retire it self too far on the other side and so by many undulations at last it comes to rest directly opposite to the pole Likewise by the declination by means of which the iron to the stone or the stone to the earth approaches in such a disposition as is most convenient to joyn the due ends together And lastly out of the flying away of the contrary ends from one another which clearly is to no other purpose but that the due ends may come together And in general there is no doubt but ones going to another is instituted by the order of nature for their coming together and for their being together which is but a perseverance of their coming together The ninth position is that The nature of a Loadstone doth not sink deeply into the main body of the earth as to have the substance of its whole body be magnetical but only remans near the surface of it And this is evident by the inequality in virtue of the two ends for if this magnetick virtue were the nature of the whole body both ends would be equally strong For would the disposition of one of the ends be different from the disposition of the other Again there could be no variation of the tending towards the North for the bulk of the whole body would have a strength so eminently greater then the prominences and disparities of hils or seas as the varieties of these would be absolutely insensible Again if the motion of the Loadstone came from the body of the earth it would be perpetually from the center not from the Poles so there could be no declination more in one part of the earth then in another Nor would the Loadstone tend from North to South but from the centre to the circumference or rather from the circumference to the centre And so we may learn the difference between the loadstone and the earth in their attractive operations to wit that the earth doth not receive its influence from another body nor doth its magnetick virtue depend of another magnetick agent that impresses it into it which nevertheless is the most remarkable condition of a Loadstone Again the stongest vertue of the Loadstone is from pole to pole but the strongest virtue of the earth is from the centre upwards as appears by fireforks gaining a much greater magnetick strength in a short time then a Loadstone in a longer Neither can it be thence objected that the loadstone should therfore receive the earths influences more strongly from the centerwards then from the poles of the earth which by its operation and what we have discours'd of it is certain it doth not since the beds where Loadstones lie and are form'd be towards the bottome of that part or back of the earth which is imbued with magnetick virtue Again this virtue which we see in a Loadstone is substantial to it wheras the like virtue is but accidental to the earth by means of the Suns drawing the northern and southern exhalations to the Equator The last position is that The loadstone must be found over all the earth and in every country And so we see it is both because iron mines are found in some measure almost in all countries cause at least other sorts of the earth as we have declared of potearths cannot be wanting in any large extent of country which when they are baked and cool'd in due positions have this effect of the Loadstone and are of the nature of it And Dr. Gilbert shews that the loadstone is nothing else but the Ore of Steel or perfectest iron and that it is to be found of all colours and fashions and almost of all consistences So that we may easily conceive that the emanations of the Loadstone being every where as well as the causes of gravity the two motions of magnetick and weighty things both of them derive their origine from the same source I mean from the very same emanations coming from the earth which by a divers ordination of nature make this affect in the loadstone and that other in weighty things And who knows but that a like sucking to this which we have shew'd in magnetick things passes also in the motion of gravity in a word gravity bears a fair testimony in behalf of the magnetick force and the Loadstones working returns no mean verdict for the causes of gravity according to what we have delivered of them CHAP. XXII A Solution of certain Problemes concerning the Loadstone and a short sum of the whole doctrine touching it OUt of what is said upon this subject we may proceed to the Solution of certain questions or problemes which are or may be made in this matter And first of that which Dr. Gilbert disputes against all former writers of the Loadstone to wit which is the North and which the South pole of a stone Which seems to me only a question of the name for if by the name of North and South we understand that end of the stone which has that virtue that the North or South pole of the earth have then 't is certain that the end of the stone which looks to the South pole of the earth is to be called the North pole of the loadstone and contrariwise that which looks to the North is to be called the South pole of it But if by the names of North and South pole of the stone yoâ— mean those ends of it that lie and point to the North and South poles of the earth then you must reckon their poles contrariwise to the former account So that the terms being once defined there will remain no further controversie about the
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
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
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
to the iron though the other steam be never so great yet it cannot draw more then according to the proportion of its Antagonists coming from the iron Wherfore seeing the two steams betwixt the iron and the little Loadstone are more proportionable to one another and the steam coming out of the little loadstone is notably greater then the steam going from the iron to the greater Loadstone the conjunction must be made for the most part to the little loadstone And if this discourse doth not hold in the former part of the Probleme betwixt a second iron and Loadstone it is supplyed by the former reason which we gave for that particular purpose The third case depends also of this solution for the bigger an iron is so many more parts it hath to suck up the influence of the Loadstone and consequently doth it therby the more greedily and therfore the Loadstone must be carried to it more violently and when they aâ—e joyn'd stick more strongly The sixth question is Why the variations of the Needle from the true North in the Northern Hemisphere are greater the nearer you go to the Pole and lesser the nearer you approach to the Equator The reason wherof is plain in our doctrine For considering that the magnetick virtue of the earth streams from the North towards the Equator it follows of necessity that if there be two streams of magnetick flowrs issuing from the North one of them precisely from the pole the other from a part of the earth near the pole that the stream coming from the point by side the Pole be but a little the stronger of the two there will appear very little differences in their several operations after they have had a long space to mingle their emanations together which therby join and grow as it were into one stream wheras the nearer you come to the Pole the more you will find them severed and each of them working by its own virtue And very near the point which causes the variation each stream works singly by it self and therfore here the point of variation must be master and will carry the needle strongly to his course from the due North if his stream be never so little more efficacious then the other Again a line drawn from a point of the Earth wide of the Pole to a point of the Meridian near the Equator makes a less angle then a line drawn from the same point of the Earth to a point of the same Meridian nearer the Pole wherfore the variation being esteem'd by the quantities of the said angles it must needs be greater near the Pole then near the Equator though the cause be the same But because it may happen that in the parts near the Equator the variation may proceed from some piece of land not much more northerly then where the needle is but that it bears rather Easterly or Westerly from it and yet Gilbert's assertion goes universally when he says the variations in Southern regions are less then in Northern ones we must examine what may be the reason therof And presently the generation of the Loadstone shews it plainly For seeing the nature of the Loadstone proceeds out of this that the Sun works more upon the Torrid Zone then upon the poles and that his too strong operation is contrary to the Loadstone as being of the nature of fire it follows evidently that the lands of the Torrid Zone cannot be so magnetical generally speaking as the polar lands are and by consequence that a lesser land near the Pole will have a greater effect then a larger continent near the Equator and likewise a land further off towards the Pole will work more strongly then a nearer land which lyes towards the Equator The seventh question is Whether in the same part of the world a touched needle may at one time vary more from the true North point and at another time less In which Gilbert was resolute for the negative part but our latter Mathematicians are of another mind Three experiences were made neer London in three divers years The two first 42 years distant from one another and the third 12 years distant from the second And by them it is found that in the space of 54 years the Loadstone hath at London diminsh'd his variation from the North the quantity of 7 degrees and more But so that in the latter years the diminution hath sensibly gone faster then in the former These observations peradventure are but little credited by Strangers but we who know the worth of the men that made them cannot mistrust any notable errour in them for they were very able Mathematicians and made their observations with very great exactness and there were several judicious witnesses at the making of them as may be seen in Mr. Gillebrand's print concerning this subject And divers other particular persons confirm the same whose credit though each single might peradventure be slighted yet all in body make a great accession We must therfore cast about to find what may be the cause of an effect so paradox to the rest of the doctrine of the Loadstone for seeing that no one place can stand otherwise to the North of the earth at one time then at another how it is possible the needle should receive any new variation since all variation proceeds out of the inequality of the earth But when we consider that this effect proceeds not out of the main body of the earth but only out of the bark of it and that its bark may have divers tempers not as yet discover'd to us out of whose variety the influence of the earthy parts may be divers in respect of one certain place 't is not impossible but that such variation may be especially in England which Island lying open to the North by a great and vast Ocean may receive more particularly then other places the special influences and variation of the weather that happen in those Northeastern countreys from whence this influence comes to us If therfore there should be any cours of weather whose period were a hundred years for example or more or lesse and so might easily pass unmarked this variation might grow out of such a cours But in so obscure a thing we have already hazarded to guess too much And upon the whole matter of the Loadstone it serves our turn if we have proved as we conceive we have done fully that its motions which appear so admirable do not proceed from an occult quality but that the causes of them may be reduced to local motion and all perform'd by such corporeal instruments and means though peradventure more intricately disposed as all other effects are among bodies Whose ordering and disposing and particular progress there is no reason to despair of finding ouâ— would men but carefully apply themselvs to that work upon solid principles and with diligent experiences But because this matter has been very long and scatteringly
through the nose of the Limbeck and falls into the receiver So that if we will say that a Plant lives or that the whole moves it self and every part moves another 't is to be understood in afar more imperfect manner then when we seak of an Animal and the same words are attributed to both in a kind of equivocal sense But by the way I must note that under the title of Plants I include not Zoophytes or Plant Animals that is such creatures as though they go not from place to place and so cause a local motion of their whole substance yet in their parts they have a distinct and articulate motion But to leave comparisons and come to the proper nature of the things Let us frame a conception that not far under the superficies of the earth there were gather'd together divers parts of little mixed bodies which in the whole sum were yet but little and that this little mass had some excess of fire in it such as we see in wet Hay or in muste of wine or in woort of beer and that withal the drought of it were in so high a degree as this heat should not find means being too much compressed to play his game and that lying there in the bosome of the earth it should after some little time receive its expected and desired drink through the benevolence of the heaven by which it being moistned and therby made more pliable and tender and easie to be wrought upon the little parts of fire should break loose and finding this moisture a fit subject to work upon should drive it into all the parts of the little mass and digesting there should make the mass swel Which action taking up long time for its performance in respect of the small increase of bulk made in the mass by the swelling of it could not be hindred by the pressing of the earth though lying never so weightily upon it according to the maxime we have above deliver'd that any little force be it never so little 't is able to overcome any great resistance be it never so powerful if the force multiply the time it works in sufficiently to equalize the proportions of the agent and the resistant This increase of bulk and swelling of the lettle mass will of its own nature be towards all sides by reason of the fire heat that occasions it whose motion is on every side from the centre to the circuÌ„ference but it wil be most efficacious upwards towards the air because the resistance is least that way both by reason of the little thickness of the earth over it as also by reason that the uper part of the earth lies very loose and is exceeding porous through the continual operation of â—e Sun and falling of rain upon it It cannot choose therfore but mount to the air and the same cause that makes it do so presses at the same time the lower parts of the mass downwards But what ascends to the air must be of the hotter and more moist parts of the fermenting mass and what goes downwards must be of his harder and drier parts proportionate to the contrary motions of fire and earth which predominate in these two kinds of parts Now this that is push'd upwards comcoming above ground and being there exposed to Sun and wind contracts thereby a hard and rough skin on its outside but within is more tender in this sort it defends it self from outward injuries of weather whiles it mounts and by thrusting other parts down into the earth it holds it self steadfast that although the wind may shake it yet it cannot overthrow it The greater this Plant grows the more juice daily accrews to it and the heat is encreased and consequently the greater abundance of humours is continually sent up Which when it begins to clog at the top new humours pressing upwards forces a breach in the skin and so a new piece like the main stem is thrust out and begins on the sides which we call a Branch Thus is our Plant amplified till nature not being able still to breed such strong issues falls to works of less labour and pushes forth the most elaborate part of the plants juice into more tender substances but especially at the ends of the branches where abundant humour but at the first not well concocted grows into the shape of a Button and more and better concocted humour succeeding it grows softer and softer the Sun drawing the subtilest parts outwards excepting what the coldness of the air and the roughness of the wind harden into an outward skin So then the next parts to the skin are tender but the very middle of this button must be hard and dry by reason that the Sun from without and the natural heat within drawing and driving out the moysture and extending it from the center must needs leave the more earthy parts much shrunk up hardned by their evaporating out from them which hardning being an effect of fire within and without that bakes this hard substance incorporates much of it self with it as we have formerly declared in the making of salt by force of fire This button thus dilated and brought to this pass we call the Fruit of the Plant whose harder part encloses oftentimes another not so hard as dry The reason whereof is because the outward hardness permits no moisture to soake in any abundance through it and then that which is enclosed in it must needs be much dried though not so much but that it still retains the common nature of the plant This drought makes these inner parts to be like a kind of dust or at least such as may be easily dried into dust when they are bruised out of the husk that incloses them And in every parcel of this dust the nature of the whole resides as it were contracted into a small quantity For the juice which was first in the button and had passed from the root through the manifold varieties of the divers parts of the plant and suffer'd much concoction partly from the Sun and partly from the inward heat imprison'd in that harder part of the fruit is by these passages strainings and concoctions become at length to be like a tincture extracted out of the whole plant and and is at last dried up into a kind of magistery This we call the Seed which is of a fit nature by being buried in the earth and dissolv'd with humour to renew and reciprocate the operation we have thus described And thus you have the formation of a Plant. But a Sensitive Creature being compared to a Plant as a plant is to mixed body you cannot but conceive that he must be compounded as it were of many plants in like sort as a plant is of many mixed bodies But so that all the Plants which concur to make one Animal are of one kind of nature and cognation and besides the matter of which such diversity is to be made must
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
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