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
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
by great noises 4. That solid bodies may convey the motion of the air or sound to the Organe of hearing 5. Where the motion is interrupted there is no sound 6. That not only the motion of the air but all other motions coming to our ears make sound 7. How one sense may supply the want of another 8. Of one who could discern sounds of words with his eyes 9. Divers reasons to prove sound to be nothing else but a motion of some real body CHAP XXIX Of Sight and Colours 1. That colours are nothing but light mingled with darkness or the disposition of a bodies superficies apt to reflect light so mingled 2. Concerning the disposition of those bodies which produce white or black colours 3. The former doctrine confirmed by Aristotles authority reason and experience 4. How the diversity of colours do follow out of various degrees of rarity and density 5. Why some bodies are diaphanous others opacous 6. The former doctrine of colours confirmed by the generation of white and black in bodies CHAP. XXX Of luminous or apparent Colours 1. Apparitions of colours through a prism or trianglar glass are of two sorts 2. The several parts of the object make several angles at their entrance into the prism 3. The reason why sometimes the same object appears through the prism in two places and in one place more lively in the other place more dim 4. The reason of the various 〈◊〉 louâ— that appear in looking thâ—rough a prism 5. The reason why the prism in one position may make the colours appear quite contrary to what they did when it was in another position 6. The reason of the various colours in general by pure light passing through a prism 7. Upon what side every colour appears that is made by pure light passing through a prism CHAP. XXXI The causes of certain appearances in luminous Colours with a conclusion of the discourse touching the Senses and the Sensible Qualities 1. The reason of each several colour in particular caused by light passing through a prism 2. A difficult problem resolved touching the Prism 3. Of the rainbow and how by the colour of any body we may know the composition of the body it self 4. That all the sensible qualities are real bodies resulting out of several mixtures of rarity and density 5. Why the senses are onely five in number with a conclusion of all the former doctrine concerning them CHAP. XXXII Of Sensation or the motion wherby sense is properly exercised 1. Monsieur des Cartes his 〈◊〉 〈◊〉 〈◊〉 2. The Authours opinion touching sensation 3. Reasons to perswade the Authours opinion 4. That vital spirits are the immediate instruments of sensation by conveying sensible qualities to the brain 5. How sound is convey'd to the brain by vital spirits 6. How colours are convey'd to the brain by vital spirits 7. Reasons against Monsieur des Cartes his opinion 8. That the symptomes of the palsy do no way confirm Monsieur des Cartes his opinion 9. That Monsieur des Cartes his opinion cannot give a good account how things are conserv'd in the memory CHAP. XXXIII Of Memosy 1. How things are conserv'd in the memory 2. How things conserv'd in the memory are brought back into the phantasie 3. A confirmation of the former doctrine 4. How things renew'd in the phantasie return with the same circumstances that they had at first 5. How the memory of things past is lost or confounded and â—en it is repaired again CHAP. XXXIV Of Voluntary motion Natural faculties and Passions 1. Of what matter the brain is composed 2. What is voluntary motion 3. What those powers are which are called natural faculties 4. How the attractive and secretive faculties work 5. Concerning the concoctive faculty 6. Concerning the retentive and expulsive faculties 7. Concerning expulsion made by Physick 8. How the brain is moved to work voluntary motion 9. Why pleasing objects do dilate the spirits and displeasing ones contract them 10. Concerning the five senses for what use and end they are CHAP. XXXV Of the material instrument of Knowledge and Passion of the several effects of passion of pain and pleasure and how the vital spirits are sent from the brain into the intended parts of the body without mistaking their way 1. That Septum Lucidum is the seat of the phansie 2. What causes us to remember not only the object it self but also that we have thought of it before 3. How the motions of the phantasie are derived to the heart 4. Of pain and pleasure 5. Of Passion 6. Of several pulses caused by passions 7. Of several other effects caused naturally in the body by passions 8. Of the Diaphragma 9. Concerning pain and pleasure caused by the memory of things past 10. How so small bodies as atomes are can cause so great motions in the heart 11. How the vital spirits sent from the brain do run to the intended part of the body without mistake 12. How men are blinded by passion CHAP. XXXVI Of some actions of Beasts that seem to be formal acts of reason as doubting resolving inventing 1. The order and connexion of the subsequent Chapters 2. From whence proceeds the doubting of beasts 3. Concerning the invention of Foxes and other beasts 4. Of Foxes that catch Hens by lying under their roost and by gazing upon them 5. From whence proceeds the foxes intention to rid himself of fleas 6. An explication of two other inventions of Foxes 7. Concerning Montagu's argument to prove that Dogs make Syllogismes 8. A declaration how some tricks are performedly Foxes which which seem to argue discourse 9. Of the Jaccatray's invention in calling Beasts to himself 10. Of the Jaccals design in serving the Lion 11. Of several inventions of fishes 12. A discovery of divers thing done by Hares which seem to argue discourse 13. Of a Fox reported to have weighed a Goose before he would venture with it over a River and of Fabulous stories in common 14. Of the several cryings and tones of beasts with a refutation of those Authors who maintain them to have compleat languages CHAP. XXXVII Of the Docility of some irrational Animals and of certain continuate actions of a long tract of time so orderly performed by them that they seem to argue knowledge in them 1. How Hawks and other creatures are taught to do what they are brought up to 2. Of the Baboon that played on a Guittar 3. Of the teaching of Elephants other beasts to do divers tricks 4. Of the orderly train of actions performed by beasts in breeding their young ones CHAP. XXXVIII Of Prescience of future events Providences the knowing of things never seen before and such other actions observed in some living Creatures which seem to be even above the reason that is in man himself 1. Why Beasts are afraid of men 2. How some qualities caused at first by change in beasts may pass by generation to the whole off spring 3. How the Parents phantasie
it is handled and on occasion return a look back upon it when it may stand him in stead If he thinks this diligence too burthensom let him consider that the writing hereof has cost the Author much more pains Who as he will esteem them exceedingly well employ'd if they may contribute ought to the content or advantage of any free and ingenuous mind so if any others shall express a neglect of what he has with so much labour hew'd out of the hard Rock of Nature or shall discourteously cavil at the Notions he so freely imparts to them all the resentment he shall make therof will be to desire the first to consider that their slight esteem of his Work obliges them to entertain their thoughts with some more noble and more profitable subject and better treated than this is and the Later sort to justifie their dislike of his doctrine by delivering a fairer and more complete body of Philosphy of their own Which if hereupon they do his being the occasion of the ones bettering themselvs and of the others bettering the world will be the best success he can wish his Book To Sir KENELME DIGBY ON His two Incomparable Treatises OF PHILOSOPHY TRuth 's numerous Proselytes in such pompous state With captiv'd judgments on your Triumph wait And mov'd by your clear Copy Wits so rare Blot out their former notions to write fair That 't were a needless duty to set forth In paper-gageants your soul-conquering worth Nor may Truth 's Champion admit a Muse Who feigns his commendation 's but abuse Unless Lucretius had bequeath'd to me His the sworn Maid to Dame Philosophy Yet ther 's a Law of gratitude which says He must pay thanks who may not offer praise When with your work you entertain'd my mind I was your Guest there I at once did find A Banquet and a Meal solid and sweet The rarely mingled in one dish did meet Such diet sure had Mankind scap't offence Had bin his meat i th' State of Ignorance And now I here give thanks which who 'll not give Who your perpetual Boarder means to live The reading your expressions forc't me speak A fancy thus charg'd needs must silence break Wherefore as Brooks to th' Sea return their streams I only here reflect your borrow'd beams Clear-faced Truth that rare unbodied light Sun to our souls wrap't in a sin-caus'd night Of ignorance who from her radiant face Darted forth nought but day had found no place In Nature's Lordships had not you in fine Plac't th' obscur'd Goddess in a Chrystal shrine We stood like men ere they begin the Mask Whose wit doth only serve to doubt and ask Untill your courteous hand remov'd the Screen Withdrew the curtains and reveal'd Truth 's Scene Some quite despairing in her quest did say She in Astraea's Coach was flown away Some said that Nature's work on purpose ti'd Like to the Gordian knot did â—ub'tly hide It's causes and effects none could unty't As if contriv'd to puzzle not delight But most avouch 't Truth in her old pit lay And our Cleantheses did oft assay With huge-long-Cart-rope Arguments to draw Her upwards with their Logick-clunched paw Bur ah their Syllogistick links all brake Yet th' obstinate peece would not her hole forsake Until your Silken Linos or deep Wit whether Reason'd not brawl'd her thence woo'd her hither Trim'd up thus natively she scorns the nighr Nor fears t'intrust her beauty to the light She through your Amber words doth brighter shine Like those in Heav'n at once both nak't and fine Clad in such Tiffany-language she grows proud To see her self in Cloathing without Cloud The Schools drest her in Linsy-Woolsy words A stile not spun of threds but writh'd of cords Expressive barbarisms fancy-woven air Whose uncouth moustrousness would make one stare An antick weed patch't up as they shall please Of Unionss Moods and Senoreities Who if they do not Priscian the disgrace To break his head they fouly scratch his face Tor'tring poor innocent Grammar to confess The truth they hide by their dark wordishness But no such stuff your noble Treatise wears It neither injures Languages nor ears Yours is a Flower-pot pav'd by Truth 's rich Gold While they in Dunghils rake for th' precious mold Your Stile 's both pure and gallant in such sort Iâ— makes the Schools speak finer than the Court With such enlihtning Metaphor as teach What sense-deluded fancy could not reach Such moving Rhetorick needs no Truth desire Such conquering Truths no Rhetorick's aid require Yet here both joyntl ' embrace as if it was Truth 's Legend writ by Sun-beams on clear Glass So that your Work all points of art affords Where equally are learn'd neat Truths true Words Fancy our Moon as Reason is our Sun Which wax't and wan'd still as she wandring run Whose visage with unconstant Aspects shone Now shuffling many things now cutting one Is taught at once 'to acknowledge and correct Her fault which gull'd the credulous Intellect And now at length is shown her double errour In the smooth steady Glass of Reason's mirrour Here Words whose whistle call'd us oft awry Are taught their Origin true sense and why Blind Prejudice cur'd by a blest amaze Opes wide her sullen eyes and stands at gaze All what the Universal Womb doth spawn Is by your Pen thence to the Life out-drawn Your Grounds are firm and sure who stirs the same May shake the World's or stronger Reason's frame Nature asserts them whose Daedalean hand Changing Particulars makes your Generals stand Here we may learn the antientest Descents And the cross Marriage of the Elements Whence Nature's numerous Family is bred In Kindred's different lines distinguished You show the secret gins the springs and wires Which the vast Engine 's motion requires You nought suppose but start your early quest Where Phoenix Nature first doth build her Nest Thence trace her laying hatching until she Brings her raw Embryo to maturity The sprouting Sap we without fiction see Creepingly metamorphos'd to a Tree We see how Eggs yield Flesh and Bone and Blood Like creatures peece-meal shap't in Nile's fat mud Our quivering grounds might have driv'n some perforce To believe A sop and grant beasts discourse Had not your Art the pretty Knack unscrew'd And it's wheeles driv'n by bloud in order shew'd Now their strange actions we may freel admire Yet not about an hidden Soul enquire No more than once Architas ' wooden Dove Ask't an Intelligence to make it move Imaginary Uacuums which are New terms for nothings emptier than air With Moods and Qualities now pack away To lurk at home in Terr' Incognita Crab'd Aristotle who did make 't his sporr Industrious wits should his obscureness court Whom like a darksome Cave none durst adventure Without a Lantern and a Guide to enter Your grounds enlightning him doth easier sound As Hebrew Conso'nants when the Points were found The Soul of Man that intellectual All Whose recreation is the World 's great Ball
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
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
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
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
end a red will now appear where in the former case a blew appear'd This case we have chosen as the plainest to shew the nature of such colours out of which he that is curious may derive his knowledge to other cases which we omit because our intent is only to give a general doctrine and and not the particulars of the Science and rather to take away admiration than to instruct the Reader in this matter As for the various colours which are made by straining light through a glass or through some other Diaphanous body to discover the causes and variety of them we must examine what things they are that concur to the making of them and what accidents may arrive to those things to vary their product 'T is clear that nothing intervenes or concurs to the producing of any of these colours besides the light it self which is dyed into colour and the glass or Diaphanous body through which it passes In them therfore and in nothing else we are to make our enquiry To begin then we may observe that light passing through a Prism and being cast upon a reflecting object is not alwayes colour but in some circumstances it still continues light and in others it becomes colour Withal we may observe that those beams which continue light and endure very little mutation by their passage making as many refractions make much greater deflexions from the straight lines by which they came into the glass then those Rays do which turn to colour As you may experience if you oppose one surface of the Glass Perpendicularly to a Candle and set a Paper not irradiated by the Candle opposite to one of the other sides of the Glass for upon the paper you shall see fair light shine without any colour and you may perceive that the line by which the light comes to the Paper is almost Perpendicular to that line by which the light comes to the Prism But when light becomes colour it strikes very obliquely upon one side of the glass and comes likewise very obliquely out of the other that sends it in colour upon a reflectent body so that in conclusion there is nothing left us whereon to ground the generation of such colours besides the littleness of the angle and the sloapingness of the line by which the illuminant strikes one side of the Glass and comes out at the other when colours proceed from such a percussion To this then we must wholly apply our selves and knowing that generally when light falls upon a body with so great a sloaping or inclination so much of it as gets through must needs be weak and much diffused it follows that the reason of such colours must necessarily consist in this diffusion and weakness of light which the more it is diffused the weaker it grows and the more lines of darkness are between the lines of light and mingle themselvs with them To confirm this you may observe how just at the egress from the Prism of that light which going on a little further becomes colours no colour at all appears upon a paper opposed close to the side of the Glass till removing it farther off the colours begin to shew themselvs upon the edges therby convincing manifestly that it was the excess of light which hindred them from appearing at the first And in like manner if you put a burning glass between the light and the Prism so as to multiply the light which goes through the Prism to the paper you destroy much of the colour by converting it into light But on the otherside if you thicken the air and make it dusky with smoak or dust you will plainly see that where the light comes through a convex glass perpendicularly opposed to the illuminant there will appear colours on the edges of the cones that the light makes And peradventure the whole cones would appear colour'd if the darkning were conveniently made for if an opacous body be set within either of the cones its sides will appear colour'd though the air be but moderately thickned which shews that the addition of a little darkness would make that which otherwise appears pure light be throughly dyed into Colours And thus you have the true and adequate cause of the appearance of such colours Now to understand what colours and upon which sides will appear we may consider that When light passes through a glass or other Diaphanous body so much of it as shines in the air or upon some reflecting body bigger then it self after its passage through the glass must of necessity have darkness on both sides of it and so be comprised and limited by two darknesses but if some opacous body less then the light be put in the way of the light then it may happen contrariwise that there be darkness or the shadow of that opacous body between two lights Again we must consider that when light falls so upon a Prism as to make colours the two outward Rays which proceed from the light to the two sides of the superficies at which the light enters are so refracted that at their coming out again through the other superficies that Ray which made the less angle with the outward superficies of the glass going in makes the greater angle with the outside of the other superficies coming out and contrariwise that Ray which made the greater angle going in makes the lesser at its coming out and the two internal angles made by those two Rays and the outside of the superficies they issue at are greater then two right angles And so we see that the light dilates it self at its coming out Now because Rays that issue through a superficies the nearer they are to be perpendiculars to that superficies so much the thicker they are it follows that this dilation of light at its coming out of the glass must be made and encrease from that side where the angle was least at the going in and greatest at the coming out so that the nearer to the contrary side you take a part of light the thinner the light must be there and contrariwise the thicker it must be the nearer it is to the side where the angle at the rays coming out is the greater Wherfore the strongest light that is the place where the light is least mixed with darkness must be nearer that side than the other Consequently hereto if by an opacous body you make a shadow comprehended within this light that shadow must also have its strongest part nearer to one of the lights betwixt which it is comprised then to the other for shadow being nothing else but the want of light hindred by some opacous body it must of necessity lie aversed from the illuminant just as the light would have lain if it had not been hindred Wherfore seeing that the stronger side of light more impeaches the darkness then the feebler side doth the deepest dark must incline to that side where the light is weakest that is
there were any defect in the consequence we should easily perceive it Whence it appears clearly that there is no parity between the deduction of our conclusion and that other which the objection urges that our Soul because it can know eternal things is also eternal for Eternity is a thing beyound our comprehension and therfore it ought not to be expected at our hands that we should be able to give an account where the brack is and to say the truth if knowledg be trken properly we do not know Eternity however by supernatural helps we may come to know it but in that case the helps are likely to be proportionable to the effect Neither are Negations properly known seeing there is nothing to be known of them And thus we see that these objections proceed from the equivocation of the word knowledg somtimes used properly othertimes apply'd abusively CHAP VIII Containing proofs out of our manner of proceeding to Action that our Soul is incorporeal I Doubt not but what we have already said hath sufficiently convinced our Souls being immaterial to whomsoever is able to penetrate the force of the arguments we have brought for proof therof and will take the pains to consider them duly which must be done by serious and continued reflection and not by cursory reading or by interrupted attempts yet since we have still a whole field of proofs untouch'd and in so important a matter no evidence can be too clear nor any pains be accounted lost that may redouble the light although it shine already bright enough to discern what we seek we will make up the concert of unanimous testimonies to this already establish'd truth by adding those arguments we shall collect out of the maner ofour Soulsproceeding to action to the others we have drawn from our observations upon her Apprehensions her Judgments and her Discourses Looking then into this matter the first consideration we meet with is that our Understanding is in her own nature an orderer that her proper work is to rank to put things in order For if we reflect on the works and arts of men as a good life a common-wealth an army a house a garden all artefacts what are they but compositions of well order'd parts And in every kind we see that he is the Master the Architect is accounted the wisest to have the best understanding who can best or most or further than his fellows set things in order If then to this we joyn that Quantity is a thing whose nature consists in a capacity of having parts and multitude and consequently is the subject of ordering and ranking doth it not evidently follow that our Soul compared to the whole mass of bodies to the very nature of corporeity or quantity is as a proper agent to its proper matter to work on Which if it be it must necessarily be of a nobler strain of a different higher nature than it and consequently cannot be a body or be composed of Quantity for had matter in it self what it expects and requires from the agent it would not need the agents help but of it self were fit to be an Agent Wherfore if the nature of corporeity or of body in its full latitude be to be order'd it follows that the thing whose nature is to be an orderer must as such be not a body but of superiour nature and exceeding a Body which we express by calling it a spiritual thing Well then if the Soul be an orderer two things belong necessarily to her one is that she have this order within her self the other that she have power to communicate it to such things as are to be order'd The first she hath by Science of which enough already hath been said towards proving our intent Next that her nature is communicative of this order is evident out of her action and manner of working But whether of her self she be thus communicative or by her conjunction to the Body she informs appears not from thence But where experience falls short Reason supplies and shews us that of her own nature she is communicative of order For since her action is an ordering and in this line there are but two sorts of things in the world namely such as order and such as are to be order'd 't is manifest that the action must by nature and in the universal consideration of it begin from the orderer in whom order hath its life and Subsistence and not from that which is to receive it then since ordering is motion it follows evidently that the Soul is a mover and begInner of motion But since we may conceive two sorts of movers the one when the agent is moved to move the other when of it self it begins the motion without being moved we are to enquire to which of these two the Soul belongs But to apprehend the question rightly we will illustrate it by an example Let us suppose that some action is fit to begin at ten of the clock Now we may imagine an agent to begin this action in two different manners one that the clock striking ten breeds or stirrs somwhat in him from whence this action follows the other that the agent may of his own nature have such an actual comprehension or decurrence of time within himself as that without receiving any warning from abroad but as though he mov'd and order'd the clock as well as his own instruments he may of himself be fit and ready just at that hour to begin that action not as if the clock told him what hour it is but as if he by governing the clock made that hour to be as well as he causes the action to begin at that hour In the first of these manners the agent is moved to move but in the second he moves of himself without being moved by any thing else And in this second way our Soul of her own nature communicates her self to quantitative things and gives them motion which follows out of what we have already proved that a Soul in her own nature is the subject of an infinite knowledg and therfore capable of having such a general comprehension as well of time the course of all other things as of the particular action she is to do and consequently stands not in need of a Monitor without her to direct her when to begin If then it be an imprevaricable law with all bodies that none whatever can move unless it be moved by another it follows that the Soul which moves without being stirr'd or excitated by any thing elseis of a higher race than they and consequently is immaterial and void of Quantity But let me not be mistaken in what I come from saying as though my meaning were that the Soul exercises this way of moving her self and of ordering her actions while she is in the Body for how can she seeing she is never endew'd with compleat knowledg requisite for any action never fully
concerning the motion of the heart 5. The motion of the heart depends originally of its fibers irrigated by bloud 6. An objection answer'd against the former doctrine 7. The Circulation of the Bloud and other effects that follow the motions of the heart 8. Of Nutrition 9. Of Argumentation 10. Of Death and Sickness 1. The connxeion of the subsequent chapters with the precedent 2. Of the Senses and sensible qualities in general And of the end for which they serve 3. Of the sense of Touching and that both it and its qualities are bodies 4. Of the Tast and its qualities that they are bodies 5. That the Smell and its qualities are real bodies 6. Of the conformity betwixt the two Senses of Smelling and Tasting 7. The reason why the sense of Smelling is not so perfect in man as in beasts with a wonderful history of a man who could wind a scent as a well as any beast 1. Of the sense of Hearing and that Sound is purely motion 2. Of divers arts belonging to the sense of Hearing all which confirm that Sound is nothing but motion 3. To same is confirm'd by the effects caused by great noises 4. That solid bodies may convey the motion of the ayr or sound to the organ of hearing 5. Where the motion is interrupted there is no sound 6. That not only the motion of the air but all other motions coming to our ears make sounds 7. How own sense may supply the want of an other 4. Of one who could discern sounds of words with his eyes 9. Divers reasons to prove sound to be nothing else but a motion of some real body 1. That Colours are nothing but light mingled with darkness or the disposition of a bodies superficies apt to reflect light so mingled 2. Concerning the disposition of those bodies which produce white or black coulours 3. The former doctrine confirm'd by Aristotles authority reason experience 4. How the diversity of colours follows out of various degrees of rarity and density 5. Why some bodies are Diaphanous others Opacous 6. The former doctrine of colours confirm'd by the generation of white and black in bodies 1. Apparitions of colours through a Prism or triangular-glass are of two sorts 2. The several parts of the object make several angles at their entrance into the Prism 6 The reason why somtimes the same object appears through the Prism in two places and in one place mor lively in the other place more dim 4 The reason of the various colours that appear in looking through a Prism 5. The reason why the Prism in one position may make the colours appear quite contrary to what they did when it was in another position 6. The reason of the various colours in general by pure light passing through a Prism 7. Upon what side every colour appears this is made by pure light passing through a Prism 1. The reason of each several colour in particular caused by light passing through a Prism 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 â—ing the Prism 3 Of the Rainbow and how by the colour of any body we may know the composition of the body it self 4 That all the Sensible Qualities are real bodies resulting out of several mixtures of Rarity and Density 5 Why the Senses are only Five in number with a conclusion of all the former doctrine concerning them 1. Monsir des Cartes his opinion touching Sensation 2. The Authors opinion touching sensation 3. Reasons to perswade the Authors opinion 4. That Vital Spirits are the immediate instruments of Sensation by conveying sensible qualities to the brain 5. How found is convey'd to the brain by vital spirits 6. How colours are convey'd to the brain by Vital Spirits 7. Reasons against Monsir des Cartes his opinion 8. That the symptome of the Palsie do no way confirm Monsir des Cartes his opinion 9. That Mâ—asir des Cartes his opinion cannot give a good account how things are conserv'd in the Memory 1. How things are conserv'd in the Memory 2. How things conserv'd in the Memory are brought back into the Phantasie 3. A Confirmation of the former doctrine 4. How things renew'd in the fantasie return with the same circumstances they had at first 5 How the memory of things past is lost or confounded and how it is repair'd again 1. Of what matter the brrain is composed 2. What is voluntary motion 3. What those powers are which are called Natural Faculties 4. How the Attractive and Secretive faculties work 5. Concerning the concoctive faculty 6. Concerning the Retentive and Expulsive faculties 7. Concerning expulsion made by Physick 9. How the brain is moved to work Voluntary motion 9. Why pleasing objects dilate the spirits and displeasing ones contract them 10. Concerning the Five Senses of what Use and End they are 1. That 〈◊〉 Luc dum is the seat of the fansie 2. What causes us to remember not only the object it self but also that we have thought of it before 3. How the motions of the fantasie are derived to the heart 4. Of Pain and Pleasure 5. Of Passion 6. Of several Pulses caused by Passion 7. Of several other effects caused naturally in the body by passions 8. Of the Diaphragma 9. Concerning pain and pleasure caused by the memory of things past 10. How so small bodies as atomes are can cause so great motions in the heart How the vital spirits sent from thebrain run to the intended part of the body without mistake 1. How men are blinded by passion 1. The order and connexion of the subsequent Chapters 2. From whence proceeds the doubting of beasts 3. Concerning the invention of Foxes and other beast 4. Of Foxes that catch hens by lying under their roost and by gazing upon them 5. From whence proceeds the Foxes invention to rid himself of Flea 6. An explication of two other inventions of Foxes 7. Concerning Montagues argument to prove that Dogs make syllogisms 8. A declaration how some tricks are perform'd by Foxes which seem to argue discourse 9. Of the Jaccatrays invention in calling beasts to himself 10. Of the Jaccils designe in serviâ—g the Lion 11. Of several intentions of Fishes 12 A discovery of divers things done by Hares which seem to argue discourse 13. Of a Fox reported to have weighâ— a Goose before he would venture with it over a River and of fabulous stories in common 14. Of the several Cryings and Tones of Beasts with a refutation of those Authors who maintain them to have compleat Languages 1. How Hawks and other creatures are taught to do what they are brought up to 2. Of the Baboon that plaid on a Guittar 3 Of the teaching of Elephants and other beasts to do divers tricks 4. Of the orderly â—ain of actions perrformd by 〈◊〉 in breeding their young ones 1. Why beasts are afrad of men 2. How some qualities caus'd at first by chance in beasts may pass by generation to the whole off-spring 3. How the parents fantasy oftentimes works strange