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
other things be seen as being accompanied by light is called Fire What admits the illuminative action of fire and is not seen is called Air What admits the same action and is seen in the rank of Elements is called Water And what through the density of it admits not that action but absolutely reflects it is called Earth And out of all we said of these four Elements it is manifest there cannot be a fifth as is to be seen at large in every Aristotelian Philosopher that writes of this matter I am not ignorant that there are sundry objections used to be made both against these notions of the First Qualities and against the division of the Elements but because they and their solotions are to be found in every ordinary Philosopher and not of any great difficulty and that the handling them is too particular for the design of this discourse and would make it too prolix I refer the Reader to seek them for his satisfaction in those Authors that treat Physick professedly and have deliver'd a compleat body of Phylosophy And I will end this Chapter with advertising him lest I should be misunderstood that though my disquisition here has pitch'd on the four bodies of Fire Air Water and Earth yet it is not my intention to affirme that those which we ordinary call so and fall daily within our use are such as I have here express'd them or that these Phlosophicall ones which arise purely out of the combination of the first qualities have their residence or consistence in great bulks in any places of the World be they never so remote as Fire in the hollow of the Moons Orb Water in the bottom of the Sea Air above the Clouds and Earth below the Mines But these notions are onely to serve for certain Idea's of Elements by which the forenamed bodies and the compounds of them may be tryed and receive their doom of more or lesse pure and approaching to the nature from whence they have their denomination And yet I will not deny but that such perfect Elements may be foumd in some very little quantities in mixed bodies and the greatest abundance of them in these four known bodies that we call in ordinary practise by the names of the pure ones for they are least compounded and approach most to the simpleness of the Elements But to determine absolutely their existence or not existence either in bulk or in little parts depends of the manner of action among bodies which as yet we have not medled with CHAP. V. Of the operations of the Elements in general And of their activities compared with one another HAving by our former discourse inquired out what degrees and proportions of rarity and density compounded with gravity are necessary for the production of the Elements and first qualities whose combinations frame the Elements our next consideration in that orderly progress we have proposed to our selves in this Treatise wherein our aim is to follow successively the steps which nature has printed out to us will be to examine the operations of the Elements by which they work upon one another To which end let us propose to our selves a rare and a dense body encountring one another by the impulse of some exterior agent In this case 't is evident that since rarity implyes a greater proportion of quantity and quantity is nothing but divisibility rare bodies must needs be more divisible then dense ones and consequently when two such bodies are press'd one against another the rare body not being able to resist division so strongly as the dense one is and being not permitted to retire back by reason of the extern violence impelling it against the dense body it follows that the parts of the rare body must be sever'd to let the dense one come between them and so the rare body becomes divided and the dense body the divider And by this we see that the notions of divider and divisible immediately follow rare and dense bodies and so much the more properly agree to them as they exceed in the qualities of Rarity and Density Likewise we are to observe in our case that the dense or dividing body must necessarily cut and enter further and further into the rare or divided body and so the sides of it be joyn'd successively to new and new pars of the rare body that gives way to it and forsake others it parts from Now the rare body being in a determinate situation of the Universe which we call being in a place and is a necessary condition belonging to all particular bodies and the dense body comming to be within the rare body whereas formerly it was not so it follows that it loses the place it had and gains another This effect is that which we call local motion And thus we see by explicating the manner of this action that locall motion is nothing else but the change of that respect or relation which the body moved has to the rest of the Universe following out of Division and the name of Locall Motion formerly signifies only the mutation of a respect to other extrinsecall bodies subsequent to that division And this is so evident and agreeable to the notions that all mankind who as we have said is judge and master of language naturally frames of place as I wonder much why any will labour to give other artificall and intricate doctrine of this that in it self is so plain and clear What need is there to introduce an imaginary space or with Johannes Grammaticus a subsistent quantity that must run through all the World and then entail to every body an aiery entity an unconceiveable mood an unintelligible Ubi that by an intrinsecall relation to such a part of the imaginary space must thereto pin and fasten the body it is in It must needs be a ruinous Phylosophy that is grounded upon such a contradiction as is the allotting of parts to that which the Authors themselvs upon the matter acknowledge to be merely nothing and upon so weak a shift to deliver them from the inconveniences that in their course of doctrine other circumstances bring them to as is the voluntary creating of new imaginary Entities in things without any ground in nature for them Learned men should express the advantage and subtilty of their wits by penetrating further into nature then the vulgar not by vexing and wresting it from its own course They should refine and carry higher not contradict and destroy the notions of mankind in those things it is the competent judge of as it undoubtedly is of those primary notions which Aristotle has rank'd under Ten Heads which as we have touched before every one can conceive in gross and the work of Scholars is to explicate them in particular and not to make the Vulgar believe they are mistaken in framing those apprehensions that nature taught them Out of that which hath been hitherto resolvd 't is manifest that Place really and abstracting from
bodies are framed Out of which discourse we may ballance the degrees of solidity in bodies For all bodies being composed of humide and dry parts we may conceive either kind of those parts to be bigger or lesser or to be more rare or more dense Now if the dry parts of any body be extreme little and dense and the moist parts that joyn the dry ones together be very great and rare then that body will be very easie to be dissolv'd But if the moist parts which glew together such extreme little and dense dry parts be either lesser in bulk or not so rare then the body composed of them will be in a stronger degree of consistence And if the moist parts which serve for this effect be in an excess of littleness and withal dense then the body they compose will be in the highest degree of consistence that nature can frame On the other side if you glew together great dry parts which are moderately dense great by the admixtion of humid parts that are of the least size in bulk and dense withal then the consistence will decrease from its height by how much the parts are greater and the density less But if to dry parts of the greatest size and in the greatest remisness of density you add humid parts both very great and very rare then the composed body will prove the most easily dissolveable of all that nature affords After this casting our eyes a little further towards the composition of particular bodies we shall find still greater mixtures the further we go for as the first and simplest compounded bodies are made of the four Elements so others are made of these and again a third sort of them and so on-wards according as by motion the parts of every one are broken in sunder and mingled with others Those of the first order must be of various tempers according to the proportions of the Elements whereof they are immediatly made As for example such a proportion of Fire to the other three Elements will make one kind of simple body and another proportion will make another kind and so throughout by various combinations and proportions among all the Elements In the effecting of which work it will not be amiss to look a little upon nature and observe how she mingles and tempers different bodies one with another wherby she begets that great variety of creatures we see in the World But because the degrees of composition are infinite according to the encrease of number we will contain our selves within the common notions of excess in the four primary components for if we should descend once to specifie any determinate proportions we should endanger losing our selvs in a wood of particular natures which belong not to us at present to examin Then taking the four Elements as materials to work upon let us first consider how they may be varied that differing compositions may result out of their mixtures I conceive that all the ways of varying the Elements in this regard may be reduced to the several sizes of Bigness of the Parts of each Element that enter into the composition of any body and to the Number of those Parts for certainly no other can be imagin'd unless it were variety of Figure But that cannot be admited to belong in any constant manner to those least particulars wherof bodies are framed as if determinate figures were in every degree of quantity due to the natures of Elements and therfore the Elements would conserve themselves in those figures as well in their least atoms as massie bulk For seeing how these little parts are shuffled together without any order and that all liquids easily joyn and take the figures which the dense ones give them and that they again justling one another crush themselves into new shapes to which their mixture with the liquid ones makes them yield the more easily t is impossible the elements should have any other natural figure in these their least parts then such as chance gives them But that one part must be bigger then another is evident for the nature of rarity and density gives it the first of them causing divisibility into little parts and the latter hindring it Having then settled in what manner the Elements may be varied in the composition of bodies let us now begin our mixture In which our ground to work upon must be Earth and Water For only these two are the Basis of permanent bodies that suffer our senses to take hold of them and submit themselvs to trial Wheras if we should make the predominant Element to be Air or Fire and bring in the other two solid ones under their jurisdiction only to make up the mixture the compound resulting out of them would be either in continual consumption as ordinary fire is or else through too much subtlety imperceptible to our eyes or touch therfore not a fit subject for us to discourse of especially since the other two Elements afford us enough to speculate on Peradventure our Smel might take some cognisance of a body so composed or the effect of it taken in by respiration might in time shew it self upon our health but it concerns not us now to look so far our design requires more maniable substances Of these then let Water be the first and with it we will mingle the other three elements in excess over one another by turns but stil all of them oversway'd by a predominant quantity of water and then let us see what kind of bodies will result out of such proportions First if earth prevail above fire and air and arrive next in proportion to the water a body of such a composition must needs prove hardly liquid and not easie to let its parts run a sunder by reason of the great proportion of so dense a body as earth that holds it together Yet some inclination it will have to fluidness by reason the water is predominant over all which also will make it be easily divisible and give every little resistance to any hard thing that shall be apply'd to make way through it In a word this mixture makes the constitution of Mud Dirt Honey Butter and such like things where the main parts are great ones And such are the parts of earth and water in themselvs Let the next proportion of excess in a watry compound be of air which when it prevails incorporates it self chiefly with earth for the other Elements would not so well retain it Now because its parts are subtile by reason of the rarity it hath and sticking because of its humidity it drives the earth and water likewise into lesser parts The result of such a mixture is that the parts of a body compounded by it are close catching flowing slowly glibb and generally it will burn and be easily converted into flame Of this kind are those we call Oyly or unctuous bodies whose great parts are easily separated that is easily divisible
in bulk but the small ones very hardly Next the smalness and well-working of the parts by means of the airs penetrating every dense one and sticking close to every one of them and consequently joyning them without any unevenness causes that there can be no ruggedness in it and therfore 't is glibb in like manner as we see plaister or starch become smooth when they are well wrought Then the humidity of it causes it to be catching and the shortness of every part makes that where it sticks it is not easily parted thence Now the rarity of air next to fire admits it to be of all the other Elements most easily brought to the height of fire by the operation of fire upon it And therfore oyls are the proper food of that Element And accordingly we see if a drop of oyl be spill'd upon a sheet of paper and the paper set on fire at a corner as the fire comes near the oyl the oyl will disperse and spread it self upon the paper to a broader compass then it had because the heat rarifies it and so in Oyl it self the fire rarifying the air makes it penetrate the earthy parts adjoynd to it more then it did and so subtilizes them till they be reduced to such a height as they are within the power of fire to communicate its own nature to them and thus it turns them into fire and carries them up in its flame But if fire be predominant over earth and air in a watry compound it makes the body so proportion'd to be subtile rare penetrative hot in operation light in weight and subject to burn Of this kind are all sorts of wines and distil'd Spirits commonly called strong waters or Aquavites in Latine Aquaeardentes These will lose their virtues meerly by remaining uncover'd in the air for fire doth not incorporate strongly with water but if it find means raises it self into the air As we see in the smoke of boyling water which is nothing else but little bodies of fire that entring into the water rarifie some parts of it but have no inclination to stay there and therefore as fast as they can get out fly away but the humide parts of the water which they have rarified being of a sticking nature joyn themselves to them and ascend in the air as high as the fiery atomes have strength to carry them which when it fails them that smoke falls down in a dew and so becomes water again as it was All which one may easily discern in a glasse-vessel of water set over the fire in which one may observe the fire come in at the bottome and presently swim up to the top like a little bubble and immediately rise from thence in smoke and that will at last convert it self into drops and settle upon some solid substance thereabouts Of these fiery spirits some are so subtile as of themselves they will vanish and leave no residue of a body behind them and Alchymists profess to make them so etherial and volatile that being pour'd out of a glass from some reasonable height they shall never reach the ground but before they come thither be so rarified by that little motion as they shall grow invisible like the air and dispersing themselves all about in it fill the chamber with the smell of that body which can no longer be seen The last excess in watery bodies must be of water it self which is when so little a proportion of any of the other is mingled with it as is hardly perceptible Out of this composition arise all those several sorts of juices or liquors we commonly call Waters which by their mixture with the other three Elements have peculiar properties beyond simple Elemental water The general quality whereof we shall not need any further to express because by what we have already said of water in common they are sufficiently known In our next survey we will take Earth for our ground to work upon as hitherto we have done water which if in any body it be in the utmost excess beyond all the other three then rocks and stones will grow out of it whose driness and hardness may assure us that Earth sways in their composition with the least allay that may be Nor doth their lightness in respect of some other earthy compositions impeach this resolution for that proceeds from the greatness and multiplicity of pores wherwith their driness causes them to aboundâ— and hinders not but that their real solid parts may be very heavy Now if we mingle a considerable proportion of water with earth so as to exceed the fire and air but still inferiour to the earth we shall poduce metals whose great weight with their ductility and malleability plainly tells us that the smallest of waters gross parts are the glew that holds the earthy dense ones together such weight belonging to earth and that easie changing of parts being most proper to water Quick-silver that is the general matter wherof all the metals are immediately composed gives us evidence hereof for fire works upon it with the same effect as upon water And the calcination of most of the metals proves that fire can easily part and consume the glew by which they were closed and held together which therfore must be rather of a watry then of an aiery substance Likewise the glibness of Mercury and of melted metals without catching or sticking to other substances gives us to understand that this great temper of a moist Element with earth is water and not air and that the watry parts are comprised and as it were shut up within the earthy ones for air catches and sticks notably to all things it touches and will not be imprisoned the divisibility of it being excceeding great though in never so short parts Now if air mingles it self with earth and be prodominant over water and fire it makes such an oily and fat soil as Husbandmen account their best mould which receiving a betterment from the Sun temperate heat assures us of the concourse of the aire for wherever such heat is air cannot fail of accompanying or being effected by it and the richest of such earth as pot-earth and marl will with much fire grow more compacted and stick closer together then it did as we see in baking them into pots or fine bricks Whereas if water were the glew between the dense parts fire would consume it and crumble them asunder as it doth in those bodies it calcines And excesse of fire will bring them to vitrification which still confirms that air abounds in them for it is the nature of air to stick so close where once it is kneaded in as it cannot be separated without extreme difficulty And to this purpose the viscuous holding together of the parts of glass when it is melted shews evidently that air abounds in vitrified bodies The last mixture we are to meddle with is of fire with earth in an over-ruling
touching Gravity 6. Gravity and levity do not signifie an intrinsecal inclination to such a motion in the bodies themselvs which are term'd heavy and light 7. The more dense a body is the more swiftly it descends 8. The velocity of bodies descending doth not encrease in proportion to the difference that may be between their several densities 9. More or less gravity produces a swister or a slower descending a heavy body Aristotles argument to disprove motion in 〈◊〉 is made good 10. The reason why at the inferior quarter of a circle a body descends faster by the arch of that quarter then by the chord of it 1. The first objection answered why a hollow body descends flower then a solid one 2 The second objection answer'd and the reasons shown why atoms continually overtake the descending dense body 3. A curious queston left undecided 4. The fourth objection answer'd Why the descent of the same heavy bodies is equal in so great inequality of the atoms which cause it 5. The reason why the shelter of a thick-body doth not hinder the descent of that which is under it 6. The reason why some bodies sink others swims 7. The fifth objection answer'd concerning the descending of heavy bodies in streams 8. The sixth objection answered and that all heavy Elements do weigh in their own Spheres 9 The seventh objection answer'd and the reason why we do not feel the course of the air and atoms that beat continually upon us 10. How in the some body gravity may be greater than density and density than gravity though they be the same thing 11. The opinion of gravities being an intrinsecal inclination of a body to the centre refuted by reason â—2 The same opinion refuted by several experiences 1. The State of the question touching the cause of violent motion 2 That the medium is the only cause which continues violent motion 3. A further explication of the former Doctrine 4. That the air has strength enough to continue violent motion in a moveable Dial. 1. of motion pag. 98. 5. An answer to the first objection that air is not apt to conserve motion And how violent motion comes to cease 6. An answer to the second objection that the air has no power over heavy bodies 7. An answer to the third objection that an arrow should fly faster broadways than long ways 1. That reflection is a kind of violent motion 2. Reflection is made at equal angles 3. The causes and properties of Undulation 4. Refraction at the entrance into the reflectent body is towà rds the perpendicular at the going out is from it when the second superficies is parallel to the first 6. An answer to the arguments brought in favovr of Monsir des Cartes his opinion 7. The true cause of refraction of light both at its entrance and at its going out from the reflecting body 8. A general rule to know the nature of reflections and refractions in all sorts of surfaces 9. A body of greater parts and greater pores makes a greater refraction than one of lesser parts and lesser pores 10. A confirmation of the former doctrine out of the nature of bodies that refract light 1. The connexion of this Chapter with the rest and the Authors intent in it 2. That there is a least size of bodies And that this least size is found in fire 3. The first conjunction of parts is in bodies of least size and it is made by the force of Quantity 4. The second sort of conjunction â—s compactedness in simple Elements and it proceeds from Density 5. The third conjunction is of parts of different Elements and it proceeds from quantity and density together 6. The reason why liquid bodies easily joyn together and dry ones difficultly 7. That no two hard bodies can touch one another immediately 8. How mixed bodies are framed in general 9. The cause of the several degrees of solidity in mixed bodies 10. The rule whereto are reduced all the several combinations of Elements in compounding of mixed bodies 11. Earth and water are the Basis of all permanent mixed bodies 12. What kind of bodies those are where water is the Basis and earth the pedominant element over the other two 13. Of these bodies where water bing the B sis air is the predominant Element 14. What kind of bodies result where water is the Basis and fire the predominant Element 15. Of those bodies where water is in excess it alone being both the Basis and the predominant Element 16. Of those bodies were Earth alone is the Basis and also the predominant in excess over the other three Elements 17. Of those bodies where Earth is the basis and Water the predominant Element over the other two 18. Of those bodies where earth being the basis air is the predominant 19. Of those bodies where earth being the basis fire is the predominant 20. All the Second Qualities of mixed bodies arise from several combinations of the First Qualities and are at last resolv'd into several degrees of rarity and density 21. That in the Planets and Stars there is a like variety of mixed bodies caused by light as here upon Earth 22. In what manner the Elements work upon one another in the position of mixed bodies and in particular fire is the most active 23. A particular declaration touching the generation of Metals 1. Why some bodies are brittle and others tough or apt to withstand outward violence the first instrument to dissolve mixed bodies 2. How outward violence work upon the most compacted bodies 3. The several effects of fiâ—e the second and chiefest instrument to dissolve compounded bodies 4. The reason why some bodies are not dissolv'd by fire 5. The reason why fire melts gold but cannot consume it 6. Why Lead is easily consumed and calcined by fire 7. Why and how some bodies are divided by fire into spirits waters oyls salts and earth what those parts are 〈◊〉 How water the third instrument to dissolve bodies dissolves Calx into Salt and so into Terra damnata 9. How water mingled with salt becomes almost powerfull Agent to dissolve other bodies 20. How putrefaction is caused 1. What is the Sphere of Activity in corporeal Agents 2. The reason why no body can work in distance 3. An objection answer'd against the manner of explicating the former Axiome 4 Of reaction and first in pure local motion that each Agent must suffer in acting and act in suffering 5. The former doctrine applyed to other local motions design'd by particular names And that Suisseths argument is of no force against this way of doctrine 6. Why some notions admit of intension and remission and others not 7. That in every part of our habitable world all the four Elements are found pure in smal atoms but not in any great bulk 1. The Authors intent in this and the following chapters Mr. Thomas White 2. That bodies may be rarified both by outward and inward heat and how this is perform'd 3.
of this subject but to enumerate the several specieses of Quantity according to that division which Logitians for more facilitie of discourse have made of it Namely these six Magnitude Place Motion Time Number and Weight Of which the two first are Permanent and lie still exposed to the pleasure of whoever has a mind to take a survey of them Which he may doe by measuring what parts they are divisible into how many ells feet inches a thing is long broad or deep how great a place is whether it be not biger or lesser then such another and by such considerations as these which all agree in this that they express the essence of those two Specieses of Quantity to consist in a Capacity of being divided into parts The two next Motion and Time though they be of a fleeting propriety yet 't is evident that in regard of their original and essential nature they are nothing else but a like divisibility into parts which is measured by passing over so great or so little distance and by years days hours minutes and the like Number we also see is of the same nature for it is divisible into so many determinate parts and is measured by unities or by lesser numbers so or so often contain'd in a proposed greater And the like is evident of Weight which is divisible into pounds ounces drams or grains and by them is measured So that looking over all the several specieses of Quantitie 't is evident our definition of it is a true one and expresses fully the essence of it when we say it is Divisibilitie or a Capacitie to be divided into parts and that no other notion whatever besides this reaches the nature of of it CHAP. III. Of Rarity and Density I Intend in this Chapter to look as far as I can into the nature and causes of the two first differences of Bodies which follow out of Quantity as it concurs with Substance to make a Body for the discovery of them and of the various proportions of them among themselves will be a great and important step in the journey we are going But the scarcity of our language is such in subjects remov'd from ordinary conversation though in others I think none is more copious or expressive as affords us not apt words of our own to express significantly such notions as I must busie my self about in this discourse therefore I will presume to borrow them from the Latine School where there is much adoe about them I would express the difference between bodies that under the same measures and outward bulk have a greater thinness and expansion or thickness and solidity one than another which terms or any I can find in English do not signifie fully those differences of Quantity which I intend here to declare therefore I will do it under the names of Rarity and Density the true meaning of which will appear by what we shall hereafter say 'T is evident to us that there are different sorts of Bodies of which though you take equal quantities in one regard yet they will be unequal in another Their magnitudes may be the same but their weights will be different or contrarywise their weights being equal their outward measures will not be so Take a pinte of Air and weigh it against a pinte of Water and you will see the ballance of the last go down amain but if you drive out the Aire by filling the pinte with Lead the other pinte in which the Water is will rise again as fast which if you pour out and fill that pinte with Quicksilver you will perceive the Lead to be much lighter and again you will find a pinte of Gold heavier then so much Mercury And in like manner if you take away of the heavy bodies till they agree in weight with the lighter they wil take up fill different proportions and parts of the measure that shall contain them But whence this effect arises is the difficulty we would lay open Our measures tel us their quantities are equal and reason assures us there cannot be two bodies in one and the same place therfore when we see a pinte of one thing outweighs a pinte of another that is thiner we must conclude there is more body compacted together in the heavy thing than in the light for else how could so little of a solid or dense thing be stretch'd out to take up so great room as we see in a basin of water that being rarified into smoke or air fills the whole chamber and again shrink back into so little room as when it returns into water or is contracted into ice But how this comprehension of more body in equal room is effected doth not a little trouble Philosophers To find a way that may carry us through these difficulties arising out of the Rarity and Density of Bodies let us do as Astronomers when they inquire the motions of the Spheres and Planets they take all the Phenomena or several appearances of them to our eyes and then attribute to them such Orbs courses and periods as may square and fit with every one of them and by supposing them they can exactly calculate all that will ever after happen to them in their motions So let us take into our consideration the chief properties of rare and dense bodies and then cast with our selvs to find out an hypothesis or supposition if it be possible that may agree with them all First it seems to us that dense bodies have their parts more close and compacted than others have that are more rare and subtile Secondly they are more heavy than rare ones Again the rare are more easily divided than the dense bodies for water oyl milk honey and such like substances will not only yield easily to any harder thing than shall make its way through them but they are so apt to division and to lose their continuity that their own weights will overcome and break it wheras in iron gold marble and such dense bodies a much greater weight and force is necessary to work that effect And indeed if we look wel into it we shall find that the rarer things are as divisible in a lesser Quantity as the more dense are in a greater and the same force will break the rarer thing into more and lesser parts than it will an equal one that is more dense Take a Stick of light wood of such a bigness that being a foot long you may break it with your hands and another of the same bigness but of a more heavy and compacted wood and you shall not break it though it be two foot long and with equal force you may break a loaf of bread into more and less parts then a lump of lead that is of the same bigness Which also will resist more to the division of Fire the subtillest divider that is then so much water will For the little atomes of fire which we shall discourse on hereafter
will pierce cut out the water almost into as little parts as themselves and mingling themselves with them they will flie away together and so convert the whole body of water into subtile smoke whereas the same Agent after long working upon lead will bring it into no less parts then small grains of dust which it calcines it into And gold that is more dense then lead resists peremptorily all the dividing power of fire and will not at all be reduced into a calx or lime by such operation as reduced lead into it So that remembring how the nature of Quantity is Divisibility and considering that rare things are more divisible then dense ones we must needs acknowledge that the nature of Quantity is some way more perfectly in things that are Rare then in those that are Dense On the other side more compacted and dense things may haply seem to some to have more Quantity then those that are rare and that is but shrunk together which may be stretch'd out and driven into much greater dimensions then the Quantity of rare things taking the quantities of each equal in outward appearance As gold may be beaten into much more and thiner leaf then an equal bulk of silver or lead A wax candle will burn longer with a small light then a tallow candle of the same bigness and consequently be converted into a greater quantity of fire and air Oyl will make much more flame then spirit of wine that is far rarer then it These and such like considerations have much perplex'd Philosophers and driven them into diverse thoughts to find out the reasons of them Some observing that the dividing of a body into little parts makes it less apt to descend then when it is in greater have believ'd the whole cause of lightness and rarity to be derived from division As for example they find that lead cut into little pieces will not go down so fast in water as when it is in bulk and it may be reduced into so smal atomes that it will for some space swim upon the water like dust of wood Which assumption is prov'd by the great Galileus to whose excellent wit and admirable industry the world is beholding not only for his wonderful discoveries made in the Heavens but also for his acurate and learned declaring of those very things that lye under our feet He about the 90. page of his first Dialogue of Motion clearly demonstrates how any real medium must of necessity resist more the descent of a little piece of lead or any other weighty matter than it would a greater piece and the resistance will be greater and greater as the pieces are lesser and lesser So that as the pieces are made less they will in the same medium sink the flower and seem to have acquired a new nature of lightness by the diminution not only of having less weight in them than they had as half an ounce is less than a whole ounce but also of having in themselvs a less proportion of weight to their bulk than they had as a pound of Cork is in regard of its magnitude lighter than a pound of Lead So as they conclude that the thing whose continued parts are the lesser is in its own nature the lighter and the rarer and other things whose continued parts are greater be heavier and denser But this discourse reaches not home for by it the weight of any body being discovered by the proportion it has to the medium in which it descends it must ever suppose a body lighter than it self in which it may sink and go to the bottome Now of that lighter body I enquire what makes it be so and you must answer by what you have concluded that it is lighter then the other because the parts of it are lesse and moreseverd from one another for if they be as close together their division avails them nothing since things sticking fast together work as if they were but one and so a pound of lead though it be filed into small dust if it be compacted hard together will sink as fast as if it were one bulk Now then allowingthe little parts to be seperated I ask what other body fills up the spaces between those little parts of the medium in which your heavy body descends For if the parts of water are more sever'd then the parts of lead there must be some other substance to keep the parts of it asunder let us suppose this to be air and I ask Whether an equal part of air be as heavy as so much water or whether it be not If you say it is then the compound of water and air must be as heavy as lead since their parts one with another are as much compacted as the parts of lead are For there is no difference whether those bodies whose little parts are compacted together be of the same substance or of divers or whether the one be divided into smaller parts then the other or not so they be of equal weights in regard of making the whole equally heavy as you may experience if you mingle pin-dust with a sand of equal weight though it be beaten into far smaller divisions then the pin-dust and put them in a bag together But if you say that air is not so heavy as water it must be because every part of air hath again its parts more sever'd by some other body then the parts of water are sever'd by air And then I make the same instance of that body which severs the parts of air And so at last since there cannot actually be an infinite process of bodies one lighter then another you must come to one whose little parts filling the pores and spaces between the parts of the others have no spaces in themselves to be fil'd up But as soon as you acknowledge such a body to be lighter and rarer then all the rest you contradict and destroy all you said before For by reason of its having no pores it follows by your rule that the little parts of it must be as heavy if not heavier then the little parts of the same bigness of that body whose pores it fills and consequently it is proved by the experience we alledg'd of pin-dust mingled with sand that the little parts of it cannot by their mingling with the parts of the body in which it is immediately contain'd make that lighter then it would be if these little parts were not mingled with it Nor would both their parts mingled with the body which immediately contains them make that body lighter And so proceeding on in the same sort through all the mingled bodies till you come to the last that is immediately mingled with water you will make water nothing the lighter for being mingled with all these and by consequence it should be as heavy and as dense as lead Now that which deceiv'd the Authors of this opinion was that they had not a right intelligence of the causes
occur other arguments of no less importance to prove this verity than these we have already proposed CHAP. VII Two objections answer'd against light being fire with a more ample proof of its being such HAving then said thus much to perswade us of the corporeity of this subtile thing that so queintly plays with our eyes we will in the next place examine those objections that at the beginning we set down against its being a body and if after a through discussion of them we find they do in truth conclude nothing of what at the first sight they bear so great a shew of but that we shall be able perfectly to solve and enerve their force no body will think it rashness in us to crave leave of Aristotle that we may dissent from him in a matter that he has not look'd to the bottom of and whose opinion therin cannot be defended from plain contradictions and impossibilities 'T is true never any one man looked fo far as he into the bowels of nature he may be rightly termed the Genius of it and whoever follows his principles in the main cannot be led into errour but we must not believe that he or any man else who relies upon the strength and negotiation of his own reason ever had a priviledge of infallibility entail'd to all he said Let us then admire him for what he has deliver'd us and where he falls short or is weary in his search and suffers himself to be born down by popular opinions against his own principles which happens very seldom to him let us seek to supply and relieve him But to pursue our intent We will begin with answerin the third objection which is that if light were fire it must heat as well as enlighten where it shines There 's no doubt but it doth so as is evident by the weather-glasses and other artificiall musical instruments as Organs and Virginals that played by themselvs wâ—ch Cornelius Drebbel That admirable master of Mechanicks made to shew the King All which depends upon the rarefaction and condensation of some subtile body conserv'd in a cavity within the bulk of the whole instrument for assoon as the Sun shined they would have motion and play their parts And questionless that grew out of the rarefaction of the subtile liquor he made use of which was dilated assoon as the air was warmd by the Sun-beams Of whose operation it was so sensible that they no sooner left the Horizon but its motion ceased And if but a cloud came between the instrument and them the musick would presently go slower time And the ancient miracle of Memnons statue seems to be a juggling of the Ethiopian priests made by the like invention But though he and they found some spirituall and refined natter that would receive such notable impressions from so small alterations of temper yet it is no wonder that our gross bodies are not sensible of them for we cannot feel heat unless it be greater then that which is in our sense And the heat there must be in proportion to the heat of our bloud which is an high degree of warmth and therfore 't is very possible that an exceeding rarified fire may cause a far lesse impression of heat then we are able to feel Consider how if you set pure spirit of wine on fire and so convert it into actual flame yet it will not burn nor scarce warm your hand and then can you expect that the light of a candle which fills a great room should burn or warm you as far as it shines If you would exactly know what degree of heat and power of burning that light has which for example shines upon the wall in a great chamber in the midst wherof there stands a candle do but calculate what overproportion of quantitie all the light in the whole room bears to the quantity of the little flame at the top of the candle and that is the overproportion of the force of burning which is in the candle to the force of burning which is in so much light at the wall as in extension is equall to the flame of the candle Which when you have considered you will not quarrel at its not warming you at that distance although you grant it to be fire streaming out from â—e flame as from the spring that feeds it and extreamly dilated according to the nature of fire when it is at liberty by going so far without any other grosse body to imprison or clog it 'T is manifest that this rule of examining the proportion of burning in so much of the light as the flame is by calculating the proportion of the quantity or extension of all the light in the room to the extension of the flame of the candle and then comparing the flame of the candle to a part of light equall in extension unto it is a good and infallible one if we abstract from accidental inequalities since both the light and the flame are in a perpetual flux and all the light was first in the flame which is the spring from whence it continually flows As in a river where every part runs with a settled stream though one place be straighter and another broader yet of necessity since all the water that is in the broad place came out of the narrow it must follow that in equal portions of time there is no more water where it has the liberty of a larg channel then where the banks press it into a narrow bed so that there be no inequalities in the bottome In like manner if in a large stove a basin of water be converted into steam that rarified water which then fills the whole Stove is no more then what the Basin contain'd before and consequently the power of moistening which is in a foot 's extension for example of the stove wherein that steam is must be in proportion to the vertue of wetting in the foot extension of water as the quantity of that great room which the steam fills is to the quantity of the water contain'd in the basin For although the rarified water be not in every least part of that great place it seems to take up by reason that there is Air in which it must swim yet the power of wetting that was in the Basin of water is dilated through the whole room by the conjunction of the Myst or Dew to all the sensible parts of the Air that is in the room and consequently the power of wetting which is in any foot of that room is in a manner as much less then the power of wetting which was in the foot of water as if the water were rarified to the quantity of the whole room and no air were left with it And in the same manner it fares with dilated fire as it doth with dilated water with only this difference peradventure that Fire grows purer and more towards its own nature by dilatation whereas water becomes more mix'd and is carried
from its nature by suffering the like effect Yet dilated water will in proportion moisten more then dilated fire will burn for the rarefaction of water brings it nearer to the nature of air whose chief propriety is moisture and the fire that accompanies it when it raiseth it into steam gives it more powerful ingression into what body it meets withal whereas fire when 't is very pure and at entire liberty to stretch and spread it self as wide as the nature of it will carry it gets no advantage of burning by its mixture with air and although it gains force by its purity yet by reason of its extreme rarefaction it must needs be extreamly faint But if by the help of Glasses you will gather into less room what is diffused into a great one and so condense it as much as it is for example in the flame of a candle then that fire or compacted light will burn much more forcibly then so much flame for there is as much of it in quantity excepting what is lost in the carriage of it and it is held in together in as little room and it has this advantage besides that 't is clog'd with no grosse body to hinder the activity of it It seems to me now that the very answering this objection doth besides repelling the force of it evidently prove that light is nothing but fire in its own nature and exceedingly dilated for if you suppose fire for example the flame of a candle to be stretch'd out to the utmost expansion that you may well imagine such a gross body is capable of 't is impossible it should appear and work otherwise then it doth in light as I have shewd above And again we see plainly that light gather'd together burns more forcibly then any other fire whatever and therefore must needs be fire Why then shall we not confidently conclude that what is fire before it gets abroad and is fire again when it comes together doth likewise remain fire during all its journey Nay even in the journey it self we have particular testimony that it is fire for light returning back from the earth charg'd with little atomes as it doth in soultry gloomy weather heats much more than before just as fire doth when it is imprisoned in a dense body Philosophers ought not to judge by the same rules that the common people doth Their gross sense is all their guide and therfore they cannot apprehend any thing to be fire that doth not make it self to be known for such by burning them But he that judiciously examines the matter and traces the pedigree and period of it and sees the reason why in some circumstances it burns and in others not is too blame if he suffer himself to be led by others ignorance contrary to his own reason When they that are curious in perfumes will have their chamber fil'd with a good scent in a hot season that agrees not with burning perfumes and therfore make some odoriferous water be blown about it by their servants mouthes that are dexterous in that ministery as is used in Spain in the Summer time every one that sees it done though on a sudden the water be lost to his eyes and touch and is only discernable by his nose yet is well satisfied that the scent which recreates him is the very water he saw in the glass extremely dilated by the forcible sprouting of it out from the servants mouth and will by little and little fall down and become again palpable water as it was before and therefore doubts not but it is still water whiles it hangs in the air divided into little atomes Whereas one that saw not the beginning of this operation by water nor observ'd how in the end it shews it self again in water might the better be excused if he should not think that what he smel'd were water blown about the air nor any substance of it self because he neither sees nor handles it but some adventitious quality he knows not how adhering to the air The like difference is between Philosophers that proceed orderly in their discourses and others that pay themselves with terms which they understand not The one see evidence in what they conclude whiles the others guesse wildly at random I hope the Reader will not deem it time lost from our main drift which we take up thus in examples and digressions for if I be not much deceived they serve exceedingly to illustrate the matter Which I hope I have now rendred so plain as no man that shall have well weighed it will expect that Fire dilated into that rarified substance which mankind who according to the different appearance of things to their sense gives different names to them calls Light should burn like that grosser substance which from doing so they call fire nor doubt but that they may be the same thing more or less attenuated as leaf-gold that flies in the air as light as down is as truly gold as that in an ingot which being heavier then any other substance falls most forcibly to the ground What we have said of the unburning fire which we call light streaming from the flame of a Candle may easily be apply'd to all other lights deprived of sensible heat whereof some appear with flame others without it Of the first sort are the innoxious flames that are often seen on the hair of mens heads and horses manes on the Masts of ships over graves and fat marish grounds and the like and of the latter sort are Glow-worms and the light-conserving stones rotten wood some kinds of fish and of flesh when they begin to putrifie and some other things of the like nature Now to answer the second part of this objection That we daily see great heats without any light as well as much light without any heat and therefore light and fire cannot be the same thing You may call to mind how Dense bodies are capable of great quantities of Rare ones and thereby it comes to pass that bodies which repugn to the dilatation of flame may nevertheless have much fire inclosed in them As in a stove let the fire be never so great yet it appears not outwards to the sight although that stove warm all the rooms near it So when many little parts of heat are imprison'd in as many little cells of gross earthly substance which are like so many little stoves to them that imprisonment will not hinder them from being very hot to the sense of feeling which is most perceptible of dense things But because they are choak'd with the closeness of the gross matter wherein they are closed they cannot break out into a body of flame or light so to discover their nature which as we have said before is the most unfit way for burning for we see that light must be condensed to produce flame and fire as flame must be to burn violently Having thus clear'd the third objection as I
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
with them their way Seeing then that such a gentle motion of the air is able to put a feather out of its way notwithstanding the percussions of the atoms upon it why shall it not likewise put a piece of iron out of its way downwards since the iron hath nothing from the atoms but a determination to its way But much more why should not a strong wind or a currant of water do it since the atoms themselv's that give the iron its determination must needs be hurried along with them To this we answer that we must consider how any wind or water which runs in that sort is it self originally full of such atoms which continually and every where press into and cut through it in pursuing their constant perpetual course of descending in such sort as we shewed in their running through any hard rock or other densest body And these atoms make the wind or water primarily tend downwards though other accidental causes impel them secundarily to a sloping motion And still their primary natural motion will be in truth strongest though their not having scope to obey that but having enough to obey the violent motion makes this become the more observeable Which appears evidently out of this that if there be a hole in the bottome of the pipe that conveys water slopingly be the pipe never so long and consequently the sloping motion never so forcible yet the water will run out at that hole to obey its more powerful impulse to the centrewards rather then continue the violent motion in which it had arrived to a great degree of celerity Which being so 't is easie to conceive that the atoms in the wind or water which move perpendicularly downwards will still continue the irons motion downwards notwithstanding the Mediums sloping motion since the prevailing force determines both the iron and the Medium downward and the iron has a superproportion of density to cut its way according as the prevalent motion determines it But if the descending atoms be in part carried along down the stream by the current of wind or water yet still the current brings with it new atoms into the place of those that are carried away and these atoms in every point or place wherever they are of themselvs tend perpendicularly downwards though they are forced from the compleat effect of their tendance by the violence of the current so that in this case they are moved by a declining motion compounded of their own natural motion and the force one with which the stream carries them Now then if a dense body fall into such a current where these different motions give their several impulses it will be carried in such sort as we say of the atoms but in another proportion not in a perpendicular but in a mixt declining line compounded of the several impulses which the atoms and current give it in which also 't is to be remembred how the current gives an impulse downwards as well as sloping and peradventure the strongest downwards and the declination will be more or less according as the violent impulse prevails more or less against the natural motion But this is not all that is to be consider'd in estimating the declination of a dense bodies motion when it is sinking in a current of wind or water You must remember that the dense body it self has a particular virtue of its own namely its density by which it receivs and prosecutes more fully its determination downwards and therfore the force of that body in cutting its way through the Medium is also to be considered in this case as well as above calculating its declining from the perpendicular and out of all these causes will result a middle declination compounded of the motion of the water or wind both ways and of its own motion by the perpendicular line And since of these three causes of a dense bodies motion it s own virtue in prosecuting by its density the determination it requires is the most efficacious by much after it has once receiv'd a determination from without its declination will be but little if it be very dense and heavy But if it recede much from density as so have some near proportion to the density of the Medium the declination will be great And in a word according as the body is heavier or lighter the declination will be more or less in the some current though not exactly according to the proportion of the diminishing of its density as long as there is a superproportion of its density to the Medium since such a superproportion as we have declared heretofore makes the Mediums operation upon the dense body scarce considerable And hence you see why a stone or piece of iron is not carried out of its way as well as a feather because the stones motion downwards is greater and stronger then the motion of a feather downwards And by consequence the force that can turn a feather from its course downwards is not able to deturn a stone And if it be repli'd that it may be so order'd that the stone shall have no motion before it be in the stream of a river and notwithstanding it will still move downwards we may answer that considering the little declivity of the bed of such a stream the strongest motion of the parts of the stream must necessiariy be downwards and consequently they will beat the stone downwards And if they do not the like to a feather or other light body 't is because other parts of the stream get under the light body and beat it upwards which they have not power enough to do to the stone Sixthly it may be objected that if Elements do not weigh in their own Spheres then their gravity and descending must proceed from some other cause and not from this percussion of the atoms we attribute to it which percussion we have determin'd goes through all bodies whatever and beats upon every sensible part of them But that Elements weigh not in their own Spheres appears out of the experience of a Syphon for though one leg of a Syphon be sunk never so much deeper into the body of the water then the other leg reaches below the superficies of the water nevertheless if once the outward leg become full of water it will draw it out of the other longer leg Which it should not do if the parts of water that are comprised within their whole bulk did weigh since the bulk of water is much greater in the sunk leg then in the other and therfore these should rather draw back the other water into the Cistern then be themselves drawn out of it into the air To this we answer that 't is evident the Elements do weigh in their own Spheres at least as far as we can reach to their Spheres for we see that a ball once stuff'd hard with air is heavier then an empty one Again more water would not be heavier then less if the inward
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
change of place we must call to mind how two dense bodies moving one against the other each of them bear before them some little quantity of a rarer body immediately joyn'd to them and consequently these more rare bodies must be the first to feel the power of the dense bodies and receive impressions from their motions each of them by the opposite rare body which like an Huissier goes before to make way for his following Master that obliges him to this service Now when these rare Ushers have strugled a while like the first lightly armed Ranks of two Armies in the interjacent Field between their main Battails that follow them close at the heels they must at the length yield when they are overborn by a greater weight then they can sustain and then they recoil back as it were to save themselves by getting in among the files of the dense bodies that drove them on Which not opening to admit them and yet they still flying violently from the mastering force that pursues them they presse so hard upon what at the first pressed them on as notwithstanding their density and strength they force them to retire back for unless they do so they are not of the number of those that work upon one another And this retiring is either on both sides or but of one side If both then 't is evident how each of them is an Agent and each of them a sufferer each of them overcoming his opposite in such sort as himself likewise receives blows and loss But if only one of the dense bodies be so shocked as to recoil back then that only suffers in its body and the other suffers only in its vertue that is in the air or other rare body it sends before it which it drives with such a violence that it masters and quells the opposition of the other body before it can reach to shake the dense body before which it runs Yet that rare body must be pressed and broken into in some measure by the incounter of the other which though never so weak yet makes some resistance but much more when it comes to grapple with the dense body it self and so between them it is wounded and infeebled like those souldiers that first enter a Breach in a Town from whence when they have driven the enemy they pursue him to the Cittadel and force him from thence too and so how maimed so ever they prove they make a free and easie way without resistance for the whole body of their army to follow them and take quiet possession of that which cost them so much to win And thus we see how it may happen that one of these moving bodies doth not suffer so much as to be stay'd in its journey much less to be driven back And yet the other body at the same time work in some measure upon it by working upon what is next to it which recoiling against it must needs make some impression upon it since there can be no opposition but must have some effect Now this impression or effect though it be not perceptible by causing a contrary motion yet it must needs infeeble the virtue of the conquering Agent and deaden the celerity of its motion And thus it is evident that in all pure local motions of corporeal Agents every one of them must in some proportion suffer in acting and in suffering must act And what we have said of this kind of action may easily be apply'd to the other where the effect of local motion is design'd by a particular name as it is in the examples we gave of heating and cooling And in that the proceeding will appear to be the very same as in this For if fire heats water the water reacts again either upon the fire and cools it if it be immediate to it or else upon the interjacent air if it be at a distance from the fire And so the air is in some measure cooled by the cold atomes that issue from the water whose compass or sphere of activity being lesser then the fire 's they cannot cool so far off as others can heat but where they a rrive they give their proportion of cold in the very midst of the others army of fiery atomes notwithstanding their multitude and violence According to which doctrine our Countryman Suisseth's argument that in the Schools is held insoluble hath not so much as any semblance of the least difficult For 't is evident that such atomes of fire and water as we determine heat and cold to be may pass and croud by one another into the subjects they are sent to by divers little streams without hindring one another as we have declared of air and light and each of them be receiv'd in their own nature temper by the same subject though sense can judge only according to which of them is predominant and according to the proportion of its superiority Upon which occasion we cannot chuse but note how the doctrine of qualities is not only unable to give account of the ordinary and plain effects of nature but also uses to end in clear impossibilities and contradictions if it be driven far as this argument of Suisseth shews and many others of the like nature A fourth position among Philosophers is that Some Notions admit the denominations of Intention and remission but that others do not The reason of which we shall clearly see if we but consider how these terms of intention and remission do but express more or less of the thing that is said to be intended or remitted for the nature of more and less implyes a latitude and divisibility and therefore cannot agree with the nature of such things as consist in an indivisible being As for example to be a whole or an equal cannot be sometimes more sometimes less for they consist in such a rigorous indivisible being that if the least part imaginable be wanting it is no longer a whole if there be the least excess between two things they are no longer equal but in some other proportion then of equality in regard of one another And hence it is that Aristotle teaches us that Substance and the species of Quantity do not admit of intention and remission but that Quality doth For first in Substance we know that the signification of this word is that which makes a thing be what it is as is evident by our giving it for an answer to the question what a thing is And therfore if there were any divisibility in Substance it would be in what the thing is and consequently every division following that divisibility would make the thing another what that is another thing and so the Substance that 's pretended to be changed by intension or remission would not be divided as is supposed but would cease to be and another substance would succeed in the room of it Wherby you see that every mutation in Substance makes a new thing and that more and
which two never misses to reign whenever the water freezes and both of them argue great store of little earthy dry bodies abounding in them which sweeping over all those that ly in their way and course must of necessity be mixed with such as give them admittance which water doth very easily And accordingly we see that when in the freezing of water the Ice grows any thing deep it either shrinks about the borders or at least lies very loose so as we cannot doubt but there is a free passage more of such subtile bodies to get still to the water and freez it deeper To his second argument we ask How he knows that Ice quantity for quantity is lighter then water For though of a Spunge that is ful of water it be easie to know what the spunge weighs and what the water that was soaked into it because we can part the one of them from the other and keep each apart to examine their weights yet to do the like between Ice and water if Ice be throughout full of air as of necessity it must be we believe impossible And therfore it may be lighter in the bulk then water by reason of the great pores caus'd in it through the shrinking up of the parts of water together which pores must then necessarily be fill'd with air and yet every part by it self in which no air is be heavier then so much water And by this it appears that his last argument grounded upon the the swiming of Ice in water has no more force then if he would prove that an iron or earthen dish were lighter and consequently more rare then water because it swims upon it which is an effect of the airs being contain'd in the belly of it as it is in Ice not a sign of the metals being more rare then water Wheras on the contrary side the proof is positive and clear for us For it cannot be denied but the mingling of the water with other bodies more dense then it must of necessity make the compound also the water it self become more dense then it was alone And accordingly we see that Ice half thaw'd for then much of the air is driven out and the water begins to fill the pores wherin the air resided before sinks to the bottom as an Iron dish with holes in it wherby the water might get into it would do And besides we see that water is more Diaphanous then Ice and Ice more consistent then water Therfore I hope we shall be excused if in this particular we be of a contrary opinion to this great personage But to return to the thrid of our discourse The same that passes here before us passes also in the Sky with Snow Hail Rain Wind. Which that we may the better understand let us consider how Winds are made for they have a main influence into all the rest When the Sun by some particular occurrent raises great multitudes of Atoms from some one place and they either by the attraction of the Sun or some other occasion take their course a certain way this motion of those atoms we call a wind which according to the continuance of the matter from whence these atoms rise endures a longer or a shorter time and goes a farther or a shorter way like a river or rather like those eruptions of waters which in the Northern parts of England they call Gypsies which break out at uncertain times and upon uncertain causes and flow likewise with an uncertain duration So these winds being composed of bodies in a determinate proportion heavier then the air run their course from their height to the ground where they are supported as water is by the floor of its channel whiles they perform their carreer that is till they be wasted either by the drawing of the Sun or by their sticking and incorporating into grosser bodies Some of these winds according to the complexion of the body out of which they are extracted are dry as those which come from barren mountains cover'd with snow others are moist as those that come out of marrishy or watry places others have other qualities as of heat or cold of wholsomness or unwholsomness and the like partly from the source and partly from the bodies they are mingled within their way Such then being the nature and origine of wind if a cold one meet in the air with that moist body wherof otherwise rain would have been made it changes that moist body into Snow or into Hail if a dry wind meet with a wet body it makes it more dry and so hinders the rain that was likely to be but if the wet body overcome the dry wind it brings the wind down along with it as we see when a showre of rain allays a great wind And that all this is so experience will in some particulars instruct us as well as reason from whence the rest may be evidently infer'd For we see that those who in imitation of nature would convert water into Ice take snow or ice mingle it with some active dry body that may force the cold parts of the snow from it and then they set the water in some fit vessel in the way that those little bodies are to take which by that means entring into it strait incorporate themselves therewith and of a suden convert it into ice Which process you may easily try by mingling Salt Armoniacke with snow but much more powerfully by setting the snow over the fire whiles the glass of water to be congealed stands in it after the manner of an egg in salt And thus fire it self though it be the enemy destroyer of all cold is made the instrument of freezing And the same reason holds in the cooling of wine with snow or ice when after it has been a competent time in the snow they whose charge it is use to give the vessel that contains the wine three or four turns in the snow so to mingle through the whole body of the wine the cold receiv'd first but in the outward parts of it and by pressing too make that without to have a more forcible ingression But the whole doctrin of Meteors is so amply so ingeniously and so exactly perform'd by that never-enough-praised Gentleman Mounsir Des Cartes in his Meteorological discourses as I should wrong my self and my Reader if I dwell any longer upon this subject And whose Physical discourses had they been divulged before I had entred upon this work I am perswaded would have excused the greatest part of my pains in delivering the nature of bodies It were a fault to pass from treating of Condensation without noting so ordinary an effect of it as is the joyning together parts of the same body or of divers bodies In which we see for the most part that the solide bodies which are to be joyn'd together are first either heated or moistned that is they are rarified and then they are left to cold
may be drawn to what height one pleases However the force which nature applies to maintain the continuity of quantity can have no limit seeing it is grounded upon contradiction And therefore Galileo was much mistaken when he thought to make an instrument wherby to discover the limits of this force We may then conclude that the breaking of the water must depend from the strength of other causes As for example when the gravity is so great by increasing the bulk of the water that it will either overcome the strength of the pipe or else make the sucker of the pump rather yield way to air then draw up so great a weight for which defects if remedies be found the art may surely be inlarged without end This is particular in a Syphon that when that arm of it which hangs out of the water is lower then the superficies of the water then it will run of it self after it is once set on running by sucking The reason whereof is because the weight which is in the water pendant is greater then the weight of the ascending water and therby supplyes the want of a continual suckeâ— But if the nose of that arm that hangs out of the water be put even with the water then the water will stand still in both pipes or arms of the Syphon after thy are filled with sucking But if by the running out of the water the outward pipe grow shorter then to reach as low as the superficies of the water in the fountain from whence it runs in this case the water in each arm of the Syphon will run back into the fountain Withall it is to be noted that though the arm which is out of the water be never so long yet if it reach not lower then the superficies of the fountain the over quantity and weight of the water there more then in the other arm helps it nothing to make it run out Which is because the declivity of the other arm over-recompences this overweight Not that the weight in the shorter pipe has so much force as the weight in the longer pipe but because it has more force then the greater weight exercises therin its running for the greatest part of its force tends another way then to the end of the pipe to wit perpendicularly towards the Centre and so is hindred from effect by the great sloping or little declivity of the pipe upon which it leans But some considering how the water in that longer arm of the Syphon is more in quantity than the water in the other arm of it wherat it runs out admire why the greater quantity of water doth noâ—d raw back the less into the cistern but suffers it self to be lifted up and drain'd away as if it run steeply downwards And they imagine that hence may be deduced that the parts of water in the cistern do not weigh as long as they are within the orb of their own body To whom we answer that they should consider how that to have the greater quantity of water in the longer arme of the Syphon which arm is immersed in the water of the cistern draw back into the cistern the water in the other arm of the Syphon that hangs out in the air it must both raise as much of the water of the cistern as its own bulk is above the level which at present the whole bulk of water has and withal at the same time pull up the water in the other arm Now 't is manifest that these two quantities of water together are heavier then the water in the sunk arm of the Syphon since one of them single is equal unto it And by consequence the more water in the sunk arm cannot weigh back the less water in the hanging arm since to do that it must at the same time weigh up over and above as much more in the cistern as it self weighs But turning the argument I say that if once the arm of the Syphon that is in the air be supposed to draw any water be it never so little out of the cistern whether occasioned by sucking or by whatever other means it follows that as much water as is drawn up above the level of the whole bulk in the cistern must needs press into the sunken arm from the next adjacent parts that is from the bottom to supply its emptying and as much must of it self press down from above according to its natural course when nothing violents it to rest in the place that the ascending water which is lower then it leavs at liberty for it to take possession of And then it cannot be doubted but that this descending water having all its weight in pressing down applied to drive up the rising water in the sunk arm of the Syphon the water in the other arm of the Syphon without having all its weight in ruÌ„ning out appli'd at the same time to draw up the same water in the sunk arm this single resistant must yield to their double mastering force And consequently the water in the arm of the Syphon that is in the air must needs draw the water that is the other immersed arm as long as the end of its pipe reaches lower then the level of the water in the cistern for so long it appears by what we have said it must needs be more weighty since part of the rising water in the sunk arm of the syphon is couÌ„ erpois'd by as much descending water in the cistern And thus 't is evident that out of this experiment it cannot be infer'd that parts of water do not weigh within the orb of their own whole but only that two equal parts of water in their own orb namely that which rises in the sunken arm and that which presses down from the whole bulke in the cistern are of equal weight and ballance one another So that never so little odds between the two counterpoysing parcels of water which are in the air must needs make the water run out at that end of the syphon where the overweight of water is The Attraction whose cause next to this is most manifest is that which is made by the force of heat or fire for we see that fire ever draws air to it so notably that if in a close room there be a good fire a man that stands at the door or window especially without shall hear such a noise that he will think there is a great wind within the chamber The reason of this attraction is that fire rarifying the air next it and withall spending it self perpetually causes the air and his own body mingled together to fly up through the chimney or by some other passage Whence it follows of necessity that the next body must succeed into the place of the body that is flown away The next body generally is air whose mobility and fluidity beyond all other bodies makes it of all others the fittest to be drawn and the more of it
is drawn the more must needs follow Now if there be floating in this air any other atoms subject to the current which the air takes they must also come with it to the fire and by it be rarified and exported out of that little orb Hence it is that men with very good reason hold that fire airs a chamber as we term it that is purifies it both because it purifies it as wind doth by drawing a current of air into it that sweeps through it or by making it purifie it self by motion as a stream of water doth by running as also because those vapours which approach the fire are burned dissolv'd So that the air being noisome and unwholesome by reason of its grossness proceeding from its standing unmoved like a stagnation of dead water in a marish place the fire takes away that cause of annoyance By this very rule we learn that other hot things which participate the nature of fire must likewise in other respects have a resemblance in this quality And accordingly we see that hot loaves in a Bakers shop newly drawn out of the Oven are accounted to draw to them any infection which is in the air The like we say of onyons and other strong breathing substances which by their smel shew much heat in them In like manner 't is conceiv'd that Pigeons and Rabbets and Cats easily take infection by reason of their extraordinary warmth which they have in themselvs And this is confirm'd by the practise of Physitians who use to lay warm Pigeons newly killed to the feet wrists or heads of sick persons and young Puppies to their stomacks and somtimes certain hot gums to their navels to draw out such vapours or humours as infest the body for the same reason they hang amulets of arsenick sublimate dryed Toads or Spiders about their patients necks to draw to them venimous qualities from their bodie Hence also it is that if a man be strucken by a Viper or a Scorpion they use to break the body of the beast it self that stung him if they can get it upon the wound but if the beast be crawl'd out of their finding they do the like by some other venimous creature as I have seen a bruised Toad laid to the biting of a Viper And they manifestly perceive the apply'd body to swel with the Poyson suck'd out from the wound the patient to be reliev'd have less poyson in the same manner as by cupping-glasses the poyson is likewise drawn out from the wound so that you may see the reason of both is the very same or at least very like one another Only we are to note that the proper body of the beast out of which the venome was driven into the wound is more efficacious than any other to suck it out And the like is to be observ'd in all other kinds that such vapours as are to be drawn come better and incorporate faster in bodies of like nature then in those which have only the common conditions of heat and dryness the one of which serves to attract the other to fasten and incorporate into itself the moisture which the first draws to it So we see that water soaks into a dry body whence it was extracted almost inseparably and is hidden in it as when it rains first after hot weather the ground is presently dried after the shower Likewise we see that in most cements you must mingle a dust of the nature of the things which are to be cemented if you will have them bind strongly Out of this discourse we may yield a reason for those Magical operations which some attribute to the Devils assistance peradventure because mans wickedness hath bin more ingenious then his good will and so has found more means to hurt then to help nay when he hath arrived some way to help those very helps have undergone the same calumny because of the likeness which their operations have to the others Without doubt very unjustly if there be truth in the effects For where have we any such good suggestions of the enemy of mankind proposed to us that we may with reason believe he would duly settledly and constantly concur to the help and service of all those he so much hates as he must needs do if he be the Author of such effects Or is it not a wrong to Almighty God and to his careful instruments rather to impute to the Devil the aids which to some may seem supernatural then to them of whom we may justly believe and expect such good Offices and assistances I mean those operations both good and bad which ordinarily are called Magnetical though peradventure wrongfully as not having that property whcih denominates the loadstone One thing I may assure that if the reports be true they have the perfect imitation of nature in them As for example that the Weapons-Salve or the Sympathetick-Powder requires in the using it to be conserved in an equal moderate temper and that the weapon which made the wound or the cloth upon which the blood remains that issued from it be orderly and frequently dressed or else the wounded person will not be cured Likewise the steam or spirits which at the giving of the wound enter'd into the pores of the weapon must not be driven out of it which will be done by fire and so when it is heated by holding over coals you may see a moisture sweat out of the blade at the opposite side to the fire as far as it entred into the wounded persons body which being once all sweated out you shall see no more the like steam upon the sword neither must the blood be washed out of the bloudy cloth for in these cases the powder or salve will work nothing Likewise if there be any excess either of heat or cold in keeping the medicated weapon or cloth the patient feels that as he would do if the like excess where in any remedy that were applyed to the wound it self Likewise if the medicated weapon or bloudy cloth be kept too close no effect follows Likewise the natures of the things used in these cures are of themselves soveraign for healing the like griefs though peradventure too violent if they were apply'd in body without much attenuation And truly if we will deny all effects of this kind we must in a manner renounce all humane faith men of all sorts and qualities and many of them such in my own knowledge as I cannot question their prudence in observing or their sincerity in relating having very frequently made experience of such medicines and all affirming after one fashion to have found the same effects Adde to these the multitude of other like effects appearing or conceited to appear in other things In some Countries 't is a familiar disease with Kine to have a swelling in the soles of their feet and the ordinary cure is to cut a turf upon which they have troden with their sore foot and to hang
of necessity be more humid and figurable then that of an ordinary plant and the Artificer which works and moulds it must be more active Wherfore we must suppose that the mass of which an Animal is to be made must be actually liquid and the fire that works upon it must be so powerful that of its own nature it may be able to convert this liquid matter into such breaths and steams as we see use to rise from water when the Sun or fire works upon it Yet if the mass were altogether as liquid as water it would vanish away by heat boyling it and be dried up therfore it must be of such a convenient temper that although in some of its parts it be fluid and apt to run yet by others it must be held together as we see that unctuous things for the most part are which will swell by heat but not fly away So then if we imagine a great heat to be imprison'd in such a liquor and that it seeks by boyling to break out but that the solidness and viscousness of the substance will not permit it to evaporate it cannot chuse but comport it self in some such sort as we see butter or oyl in a frying-pan over the fire when it rises in bubbles but much more efficaciously For their body is not strong enough to keep in the heat and therfore those bubbles fall again wheras if it were those bubbles would rise higher and higher and stretch themselvs longer and longer as when the Soap-boylers boyl a strong unctuous lye into Soap and every one of them would be as it were a little brook wherof the channel would be the enclosing substance and the inward smoak that extends it might be compared to the water of it as when a glass is blown out by fire and air into a long figure Now we may remember how we have said where we treated of the Production and Resolution of Mixed bodies that there are two sorts of liquid substantial parts which by the operation of fire are sent out of the body it works upon the watery and the oyly parts For thouh there appear somtimes some very subtile and Ethereal parts of a third kind wich are the Aquae Ardentes or borning spirits yet in such a close distilling of circulation as this is they are not sever'd by themselvs but accompany the rest and especially the watery parts which are of a nature that the rising Ethereal spirits easily mingle with and extend themselves in it wherby the water becomes more efficacious and the spiritt less fugitive Of these liquid parts which the fire sends away the watry ones are the first as being the easiest to be raised the oyly parts rise more difficultly and therfore come last And in the same manner it happens in this emission of brooks the watry and oyly steams will each of them fly into different reservs and if there arrive to them abundance of their own quality each of them must make a substance of its own nature by by setling in a convenient place and by due concoction Which substance after it is made and confirm'd if more humidity and heat press it will again break forth into other little channels But when the watry and oyly parts are boyl'd away there remain yet behind other more solid and fixed parts and more strongly incorporated with fire then either of these which yet cannot drie up into a fiery salt because a continual accession of humour keeps them always flowing and so they become like a cauldron of boyling fire Which must propagate it self as wide as either of the other since the activity of it must needs be greater then theirs as being the source of motion to them and that there wants not humidity for it to extend it self by And thus you see three roots of three divers plants all in the same plant proceeding by natural resolution from one primitive source Wherof that which is most watry is fittest to fabricate the body and common outside of the triformed plant since water is the most figurable principle in nature and most susceptible of multiplication and by its cold is easiest to be hardned and therfore fittest to resist the injuries of enemy-bodies that may infest it The oily parts are fittest for the continuance and solidity of the plant for we see that viscuosity and oyliness hold together the parts where they abound and they are slowly wasted by fire but conserve and are an aliment to the fire that consumes them The parts of the third kind are fittest for the conservation of heat which though in them it be too violent yet is necessary for working upon other parts and maintaining a due temper in them And thus we have armed our plant with three sorts of rivers or brooks to run through him with as many different streams the one of a gentle balsamike oyle another of streaming fire and the third of a con-natural and cooler water to irrigate and temper him The streams of water as we have said must run through the whole fabrick of this triformed plant and because it is not a simple water but warm in a good degree and as it were a middle substance betwixt water and air by reason of the ardent volatile spirit that is with it 't is of a fit nature to swell as air doth and yet withall to resist violence in a convenient degree as water doth Therfore if from its source nature sends abundance into any one part that part must swell and grow thicker and shorter and so must be contracted that way which nature has order'd it Whence we perceive a means by which nature may draw any part of the outward fabrick which way soever she is pleased by set instruments for such an effect But when there is no motion or but little in these pipes the standing stream that is in a very little though long channel must needs be troubled in its whole body if any one part of it be press'd upon so as to receive therby any impression and therfore whatever is done upon it though at the very furthest end of it makes a commotion and sends an impression up to its very source Which appearing by our former d scourse to be the origine of particular and accasional motion 't is obvious to conceive how it is apt to be moved and wrought by such an impression to set on foot the begining of any motion which by natures providence is convenient for the plant when such an impression is made upon it And thus you see this plant hath the virtue both of sense or feeling that is of being moved and effected by extern objects lightly striking upon it as also of moving it self to or from such an object according as nature shall have ordain'd Which in sum is that This Plant is a Sensitive Creature composed of three sources the Heart the Brain and the Liver whose off-springs are the Arteries the Nervs and the Veins which are fil'd with Vital
will the same happen in so difficult and spiny an affair as the writing on such a nice and copious Subject as this is to one who is so wholly ignorant of the Laws of Method as I am This free and ingenuous acknowledgment on my side will I hope prevail with all ingenuous person who shall read what I have written to advertise me fairly if they judg it worth their while of what they dislike in it to the end that in another more accurate Edition I may give them better satisfaction For besides what failings may be in the Matter I cannot doubt but even in the Expressions of it there must often be great obscurity and shortness which I who have my thoughts filled with the things themselvs am not aware of So that what peradventure may seem very full to me because every imperfect touch brings into my mind the entire notion and whole chain of circumstances belonging to that thing I have so often beaten upon may appear very crude and maimed to a Stranger that cannot guess what I should be at otherwise than as my direct words lead him One thing more I shall wish you to desire of them who happily may peruse these two Treatises as well for their own sakes as for mine And that is that they will not pass their censure upon any particular piece or broken parcel of either of them taken by itself Let them draw the entire Thrid through their fingers and examine the consequentness of the Whole Body of the doctrine I deliver and let them compare it by a like survey with what is ordinarily taught in the Schools and if they find in theirs many bracks and short ends which cannot be spun into an even piece and in mine a fair coherence througout I shall promise my self a favourable doom from them and that they will have an acquiescence in themselvs to what I have here presented them Whereas if they but ravel it over looslie and pitch upon dispuiting against particular Conclusions that at the first encounter of them single may seem harsh to them which is the ordinary course of Flashy Wits who cannot fadome the whole extent of a large discourse 't is impossible but that they should be very much unsatisfied of me and go away with a perswasion that some such Truths as upon the whole matter are most evident one stone in the Arch supporting another and the whole are meer Chymeras and wild Paradoxes But Son 't is time my Book should speak it self rather than I speak any longer of it here Read it carefully over and let me see by the effects of your Governing your self that you make such right use of it as I may be comforted in having chosen you to bequeath it to God in Heaven bless you Paris the last of August 1644. Your loving Father KENELM DIGBY TABLE Of the First TREATISE CONCERNING BODIES PREFACE CHAP. I. A Preamble to the whole Discourse Concerning Notions in general 1. Quantity is the first and most obvious affection of a body 2. Words do not express things as they are in themselvs but only as they are painted in the minds of men 3. The first error that may arise from hence which is a multiplying of things where no such multiplication is really found 4. A second errour the conceiving many distinct things as really one thing 5. Great care to be taken to avoid the errours which may arise from our mannner of understanding things 6. Two sorts of words to express our notions the one common to all men the other proper to scholars 7. Great errours arise by wresting words from their common meaning to express a more particular or studied notion CHAP. II. Of Quantity 1. We must know the vulgar and common notion of Quantity that we may understand the nature of it 2. Extension or divisibility is the common notion of Quantity 3. Parts of Quantity aâ—e not actually in their whole 4. If parts were actually in their whole Quantity would be composed of indivisibles 5. Qantity cannot be composed of indivisibles 6. An objection to prove that parts are actually in Quantity with a declaration of the mistake from whence it proceeds 7. The solution of the former objection and that sense cannot discern whether one part be distinguished from another or no. 8. An enumeration of the several specieses of Quantity which confirmes that the essence of it is divisibility CHAP. III. Of Rarity and Density 1. What is meant by Rarity and Density 2. It is evedent that some bodies are rare and others Dense though obscure how they are such 3. A brief enumeration of the several properties belonging to rare and dense bodies 4. The Opinion of those Philosophers declared who put rarity to consist in an actual division of a body into little parts 5. The former opinion rejected and the ground of their errour discovered 6. The opinion of those Philosophers related who put rarity to consist in the mixtion of vacuity among bodies 7. The opinion of vacuities refuted 8. Rarity and Density consist in the severall proportions which Quantity hath to its Substance 9. All must admit in Physical bodies a Metaphysical composition CHAP. IV. Of the four First Qualities and of the four Elements 1. The notions of Density and rarity have a latitude capable of infinite variety 2. How moistness and driness are begotten in dense bodies 3. How moistness and dryness are begotten in rare bodie 4. Heat is a property of rare bodies and cold of dense ones 5. Of the two dense bodies the less dense is more cold but of the two rare ones the less rare is less hot 6. The extreme dense body is more dry than the extreme rare one 7. There are but four simple bodies and these are rightly named Elements 8. The Authour doth not determine whether every Element doth comprehend under its name one onely lowest species or many nor whether any of them be found pure CHAP. V. Of the operations of the Elements in general And of their Activities compared with one another 1. The first operation of the Elements is division out of which results local motion 2. What place is both notionally and really 3. Local motion is that division wherby a body changes its place 4. The nature of quantity of it self is sufficient to unite a body to its place 5. All operations amongst bodies are either local motions or such as follow out of local motion 6. Earth compared to Water in activity 7. The manner wherby fire gets into fewel proves that it exceeds earth in activity 8. The same is proved by the manner wherby fire comes out of fewel and works upon other bodies CHAP. VI. Of Light what it is 1. In what sense the Authour rejects qualities 2. In what sense the Authour admits of qualities 3. Five arguments proposed to prove that light is not a body 4. The two first reasons to prove Light a body are the resemblance it hath with fire and because if it were a
which made little parts of bodies naturally heavie descend slowly in regard of the velocity of greater parts of the same bodies descending the Doctrine of which we intend to deliver hereafter Others therfore perceiving this rule to fall short have indeavour'd to piece it out by the mixtion of Vacuitie among bodies believing it is that which makes one rarer then another Which mixtion they do not put always immediate to the main body they consider but if it have other rarer and lighter bodies mingled with it they conceive this mixtion immediate only to the rarest or lightest As for example a Crystal being lighter and consequently rarer then a Diamond they will not say there is more vacuity in a Crystal then in a Diamond but that the pores of a Crystal are greater and consequently there is more aire in a Crystal to fil the pores of it then is in a Diamond and the vacuities are in the aire which abounding in a Crystal more then in a Diamond makes that lighter and rarer then this by the more vacuites that are in the greater Quantity of aire which is mingled with it But against this suppsition a powerful adversary is urged for Aristotle in his 4. Book of Physicks hath demonstrated that there can be no motion in vacuity 'T is true they indeavour to evade his demonstration as not reaching home to their supposition by acknowledging it to be an evident one in such a vacuity as he there speaks of which he supposed so great that a body may swim in it as in an Ocean and not touch or be near any other body whereas this opinion exclude all such vast inanity admit no vacuities but so little ones as no body whatever can come to but wil be biger than they and consequently must on some side orother touch the corporal parts which those vacuities divide for they are the separations of the least parts that are or can be actually divided from one another which parts must of necessity touch one another on some side or else they could not hang together to compose one substance and and therefore the dividing vacuities must be less then the divided parts And thus no body will ever be in danger of floating up and down without touching any thing which is the difficulty that Aristotle chiefly impugns I confess I should be very glad that this supposition might serve our turne and save the Phenomena that appear among bodies through their variety of Rarity and Density Which if it might be then would I straight go on to the inquiring after what follow'd out of this ground as Astronomers to use our former similitude calculate the future appearances of the Celestial bodies out of those motions and orbs they assign to the Heavens For as this apprehension of vacuity in bodies is very easie and intelligible so the other which I conceive to be the truth of the case is exceedingly abstracted and one of the most difficult points in all the Metaphysicks and therefore I would if it were possible avoid touching upon it in this discourse which I desire should be as plain and easie and as much removed from Scholastick terms as may be But indeed the inconveniences that follow out of this supposition of vacuities are so great as it is impossible by any means to slide them over As for example let us borrow of Gallileus the proportion of weight between water and air He shews us how the one is 400 times heavier then the other And Marinus Ghetaldus teaches us that gold is 19 times heavier then water so that gold must be 7600 times heavier then air Now then considering that nothing in a body can weigh but the solid parts of it it follows that the proportion of the parts of gold in a sphere of an inch Diameter is to the parts of the air of a like dimension as 7600 is to one Therfore in air it self the vacuities that are supposed in it will be to the solid parts of it in the same proportion as 7600 to one Indeed the proportion of difference shal be greater for even in gold many vacuities must be admitted as appears by the heating of it which shews that in every least part it is exceeding porous But according to this rate without pressing the inconvenience any further the air will by this reckoning appear to be like a net whose holes distances are to the lines and threds in the proportion of 7600 to one and so would be lyable to have little parts of its body swim in those greater vacuities contrary to what they strive to avoid Which would be excedingly more if we found on the one side any bodies heavier denser then gold that were so solid as to exclude all vacuities on the other side should balance them withsuch bodies as are lighter and rarer then air as fire is and as some say will have the aether to be But already the disproportion is so great and the vacuity so strangely exceeds the body in which it is as were too great an absurdity to be admitted And besides it would destroy all motion of small bodies in the air if it be true as Aristotle hath demonstrated in the fourth Book of his Physicks that motion cannot be made but among bodies and not in vacuo Again if rarity were made by vacuity rare bodies could not be gather'd together without losing their rarity and becoming dense The contrary of which we learn by constant experience as when the Smith and Glassemender drive their white and fury fires as they term them when aire pierces most in the sharp wind and generally we see that more of the same kind of rare bodies in less place works more efficaciously according to the nature that results out of that degree of rarity Which argues that every little part is as rare as it was before for else it would lose the vertue of working according to the nature but that by their being crowded together they exclude all other bodies that before mediated between the little parts of their main body and so more parts being gotten together in the same place then formerly there were they work more forcibly Thirdly if such vacuities were the cause of rarity it would follow that fluid bodies being rarer then solid ones would be of themselvs standing like nets or cobwebs wheras contrariwise we see their natures are to run together and to fill up every little creek and corner which effect following out of the very nature of the things themselves needs must exclude vacuities out of that nature And lastly if it be true as we have shew'd in the last Chapter that there are no actual parts in Quantity it follows of necessity that all Quantity must of it self be one as Metaphysicks teach us and then no distance can be admitted between one Quantity and another And truely if I understand Aristotle right he hath perfectly demonstrated that no vacuity is possible in nature
neither great nor little and consequently the whole machine raised upon that supposition must be ruinous His argument is to this purpose What is nothing cannot have parts but vacuum is nothing because as the Adversaries conceive it vacuum is the want of a corporeal substance in an inclosing body within whose sides nothing is whereas a certain body might be contain'd within them as if in a pail or bowl of a gallon there were neither milk nor water nor air nor any other body whatever therefore vacuum cannot have parts Yet those who admit it put it expresly for a Space which essentially includes Parts and thus they put two contradictories nothing and parts that is parts and no parts or something and nothing in the same proposition And this I conceive to be absolutely unavoidable For these reasons therfore I must entreat my Readers favour that he will allow me to touch upon Metaphysicks a little more than I desire or intended but it shall be no otherwise then as is said of the Dogs by the River Nilus side who being thirsty lap hastily of the water only to serve their necessity as they run along the shore Thus then remembring how we determin'd that Quantity is Divisibility it follows that if besides Quantity there be a Substance or Thing which is divisible that Thing if it be condistinguish'd from its Quantity or Divisibility must of it self be indivisible or to speak more properly it must be not divisible Put then such Substance to be capable of the Quantity of the whole world or Universe and consequently you put it of it self indifferent to all and to any part of Quantity for in it by reason of the negation of Divisibility there is no variety of parts wherof one should be the subject of one part of Quantity or another of another or that one should be a capacity of more another of â—ess This then being so we have the ground of more or less Proportion between Substance and Quantity for if the whole Quantity of the Universe be put into it the proportion of Quantity â—o the capacity of that substance will be greater than if but half â—hat quantity were imbibed in the same substance And because proportion changes on both sides by the single change of only one side it follows that in the latter the proportion of that Substance to its Quantity is greater and that in the former 't is less though the Substance in it self be indivisible What we have said thus in abstract will sink more easily into us if we apply it to some particular bodies here among us in which we see a difference of Rarity and Density as to air water gold or the like and examine if the effects that happen to them do follow out of this disproportion between substance and Quantity For example let us conceive that all the quantity of the world were in one uniform substance then the whole universe would be of one and the same degree of Rarity and Density let that degree be the degree of water it will then follow that in what part soever there happens to be a change from this degree that part will not have that proportion of quantity to its substance which the quantity of the whole world had to the presupposed uniformsubstance But if it happens to have the degree of rarity which is in the air it will then have more quantity in proportion to its substance then would be due to it according to the presupposed proportion of the quantity of the universe to the aforesaid uniform substance which in this case is as it were the standard to try all other proportions by And contrariwise if it happens to have the degree of Density which is found in earth or in gold then it will have less quantity in proportion to its substance then would be due to it according to the aforesaid proportion or common standard Now to proceed from hence with examining the effects which result out of this compounding of Quantity with substance we may first consider that the Definitions which Aristotle has given us of Rarity and Density are the same we drive at He tells us that that body is rare whose quantity is more and its substance less that contrariwise dense where the substance is more and the quantity less Now if we look into the proprieties of the bodies we have named or of any others we shall see them all follow clearly out of these definitions For first that one is more diffused another more compacted such diffusion and compaction seem to be the very natures of Rarity and Density supposing them to be such as we have defined them to be since substance is more diffused by having more parts or by being in more parts and is more compacted by the contrary And then that rare bodies are more divisible then dense ones you see is coincident into the same conceit with their diffusion and compaction And from hence again it follows that they are more easily both divided into great and by the force of natural Agents divisible into lesser parts for both these that is facility of being divided and easie divisibility into lesser parts are contain'd in being more divisible or in more enjoying the effect of Quantity which is divisibility From this again follows that in rare bodies there is less resistance to the motion of another body through it than in dense ones and therefore a like force passes more easily through the one than through the other Again rare bodies are more penetrative and active than dense ones because being by their overproportion of quantity easily divisible into small parts they can run into every little pore and so incorporate themselvs better into other bodies than more dense ones can Light bodies likewise must be rarer because most divisible if other circumstances concur equally Thus you see decypher'd to your hand the first division of bodies flowing from Quantity as it is ordain'd to Substance for the composition of a Body for since the definition of a Body is a thing which hath parts and quantity is that by which it hath parts and the first propriety of quantity is to be bigger or lesse and consequently the first differences of having parts are to have bigger or lesse more or fewer what division of a Body can be more simple more plain or more immediate than to divide it by its Quantity as making it have bigger or less more or fewer parts in proportion to its Substance Neither can I justly be blamed for touching thus on Metaphysicks to explicate the nature of these two kinds of Bodies for Metaphysicks being the Science above Physicks it belongs to her to declare the principles of Physicks of which these we have now in hand are the very first step But much more if we consider that the composition of quantity with substance is purely Metaphysical we must necessarily allow the inquiry into the nature of Rarity and Density to be wholly Metaphysical since
compounded one will be gathered into one place and those of divers kinds into divers places which is the notion whereby Aristotle hath express'd the nature of heat and is an effect which daily experience in burning and boiling teaches us to proceed from heat And therefore we cannot doubt but such extreme rare bodies are as well hot as dry On the other side if a Dense thing be apply'd to a compound it will because it is weighty press it together and if that application be continu'd on all sides so that no part of the body that is pressed be free from the siege of the dense body that presses it it will form it into a narrower room and keep in the parts of it not permitting any of them to slip out So that what things soever it finds within its power to master be they light or heavy or of what contrary nature soever it compresses them as much as it can and draws them into a less compass and holds them strongly together making them stick fast to one another Which effect Aristotle took for the proper notion of cold and therefore gave for definition of the nature of it that it gathers things of divers natures and experience shews us in freezing and all great coolings that this effect proceds from cold But if we examine which of the two sorts of dense bodies the fluide or the consistent is most efficacious in this operation we shall find that the less dense one is more capable of being apply'd round about the body it shall besiege and therefore will stop closer every little hole and more easily send subtile parts into every little vein of it and by consequence shrink it up together and coagulate and constringe it more strongly then a body can that is extremely dense which by reason of its great density and the stubbornness of its parts cannot so easily bend and ply them to work this effect And therefore a body that is immoderately dense is colder then another that is so in excess since cold is an active or working power and that which is less dense excells in working On the contrary side rare bodies being hot because their subtile parts environing a compounded body will sink into the pores of it and to their power separate its parts it follows that those wherein the gravity overcomes the rarity are less hot then such others as are in the extremity and highest excess of rarity both because the former are not able to pierce so little parts of the resisting dense body as extreme rare ones are and likewise because they more easily take ply by the obstacle of the solid ones they meet with then these do So that out of this discourse we gather that of such bodies as differ precisely by the proportion of Rarity and Density those which are extremely rare are in the excesse of heat and are dry withall that weighty rare bodies are extremely humid and meanly hot that fluide dense bodies are moist though not in such excess as rare ones that are so but are coldest of any and lastly that extreme dense bodies are less cold then fluide dense ones and that they are dry But whether the extreme dense bodies be more or less dry then such as are extremely rare remains yet to be decided Which we shall easily do if we but reflect that it is density which makes a thing hard to be divided and rarity makes it easie for a facility to yeeld to division is nothing else but a pliableness in the thing that is to be divided wherby it easily receives the figure which the thing that divides it doth cast it into Now this plyablenss belongs more to rare then to dense things and accordingly we see fire more easily bend by the concameration of an oven then a stone can be reduced into due figure by hewing And therfore since dryness is a quality that makes those bodies wherein it reigns conserve themselves in their own figure and limits and resist the receiving of any from another body it is manifest that those are driest wherein these effects are most seen which is in dense dodies and consequently excess of dryness must be allotted to them to keep company with their moderate coldness Thus we see that the number of Elements assign'd by Aristotle is truly and exactly determin'd by him and that there can be neither more nor less of them and their qualities are rightly allotted to them Which to settle more firmly in our minds it will not be mis-spent time to sum up in short the effect of what we have hitherto said to bring us to this Conclusion First we shew'd that a body is made and constituted a Body by Quantity Next that the first division of Bodies is into Rare and Dense ones as differing only by having more less Quantity And lastly that the conjunction of Gravity with these two breeds two other sorts of combinations each of which is also twofold the first sort concerning Rarity out of which arises one extremely hot and moderately dry and another extremely humide and moderately hot the second sort concerning Density out of which is produced one that is extremely cold and moderately wet and another extremely dry and moderately cold And these are the combinations whereby are constituted Fire Air Water and Earth So that we have thus the proper notions of the Four Elements and both them and their qualities driven up and resolv'd into their most simple Principles which are the notions of Quantity and of the two most simple differences of quantitive things Rarity and Density Beyond which mans wit cannot penetrate nor can his wishes aim at more in this particular seeing he has attain'd to the knowledge of what they are and of what makes them be so and that it is impossible they should be otherwise and this by the most simple and first principles which enter into the composition of their nature Out of which it is evident these Four bodies are Elements since they cannot be resolv'd into any others by way of physicall composition themselves being constituted by the most simple Differences of a Body And again all other bodies whatever must of necessity be resolv'd into them for the same reason because no bodies can be exempt from the First defferences of a Body Since then we mean by the name of an Element a Body not composed of any former bodies and of which all other bodies are composed we may rest satisfied that these are rightly so named But whether every one of these four Elements comprehend under its name one only lowest Species or mady as whether there be one only Species of fire or several and the like of the rest we intend not here to determine Yet we note that there is a great latitude in every kind since Rarity and Density as we have said before are as divisible as Quantity Which Latitudes in the bodies we converse with are so limited that What makes it self and
the operation of the understanding is nothing else but the inward superficies of a body that compasses and immediately conteines another Which ordinarily being of a rare body that doth not shew it self to us namely the Air is for the most part unknown by us But because nothing can make impression on our minds and cause us to give it a name otherwise then by being known therfore our understanding to make a compleat notion must add something else to this fleeting and unremarkable Superficies that may bring it to our acquaintance And for this end we may consider further that as this Superficies hath in it self so the bodie enclosed in it gains a certain determinate respect to the stable and immoveable bodies that environ it As for example we understand such a Tree to be in such a place by having such and such respects to such a Hill near it or to such a House that stands by it or to such a River that runs under it or to such an immoveable point of the Heaven that from the Suns rising in the Equinox is called East and such like To which purpose it imports not whether these that we call immoveable bodies and points be truly so or do but seem so to mankind For man talking of things according to the notions he frames of them in his mind speech being nothing else but an expression to another man of the images he hath within himself and his notions being made according to the seeming of the things he must needs make the same notions whether the things be truly so in themselvs or but seem to be so when that seeming or appearance is always constantly the same Now then when one body dividing another gets a new immediate clothing and consequently new respects to the stable and immoveable bodies or seeming such that environ it we vary in our selves the notion we first had of that thing conceiving it now accompanied with other circumstances and other respects then formerly it had Which notion we express by saying it has changed its place and is now no longer where it was at the first And this change of place we call Locall motion to wit the departing of a body from that hollow superficies which inclosed it and its changing to another wherby it gains new respects to those parts of the World that have or in some sort may seem to have immobility and fixed stableness So as hence 't is evident that the substance of Locall motion consists in Division and that the alteration of Locality follows Division in such sort as the becoming like or unlike of one wall to another follows the action whereby one of them becomes white And therefore in Nature we are to seek for any entity or special cause of applying the moved body to a place as place which is but a respect consequent to the effect of division but only to consider what real and physical action unites it to that other body which is called its place and truly serves for that effect And consequently they who think they have discover'd a notable subtilty by bringing in an Entity to unite a Body to its Place have strain'd beyond their strength and grasped but a shadow Which will appear yet more evident if they but mark well how nothing is divisible but what of it self abstracting from division is one For the nature of Division is the making of many which implies that what is to be divided must of necessity be not-many before it be divided Now Quantity being the subject of division 't is evident that purely of it self and without any force or adjoyned helps it must needs be one wherever some outward agent doth not introduce multiplicity upon it And whenever other things work upon quantity as quantity it is not the nature and power of their operation to produce unity in it and make it one for it is already one but contrariwise the immediate necessary effect that flows from them in this case is to make one quantity many according to the circumstances that accompany the divider and that which is to be divided And therefore although we may seek causes why some one thing sticks faster together then some other yet to ask absolutely why a body sticks together were prejudicial to the nature of quantity whose essence is to have parts sticking together or rather to have such unity as without which all divisibility must be excluded Out of which discourse it follows that in local motion we are to look onely for a cause or power to divide but not for any to unite For the very nature of quantity unites any two parts that are indistant from one another without needing any other cement to glue them together as we see the parts of water and all liquid substances presently unite themselves to other parts of like bodies when they meet with them and to solid bodies if they chance to be next them And therefore 't is vain to trouble our heads with Unions and imaginary Moods to unite a body to the place it is in when their own nature makes them one as soon as they are immediate to each other And accordingly if when we see a Boul move we would examine the causes of that motion we must consider the quantity of air or water it makes to break from the parts next to it to give place to it self and not speculate upon an intrinsecall relation from the body to a certain part of the imaginary space they will have to run through all things And by ballancing that quantity of air or water which it divides we may arrive to make an estimate of what force the Boul needs to have for its motion Thus having declar'd that the locality of motion is but an extrinsecall denomination and no reality in the thing moved we may now cast an eye upon a vast consequence that may be deduced out of what we have hitherto said For if we consider the nature of a Body that is that a Body is a Body by quantity and that the formall notion of Quantity is nothing else but Divisibility and that the adequate Act of Divisibility is Division 't is evident there can be no other Operation upon Quantity nor by consequence among Bodies but must either be such Division as we have here explicated or what must necessarily follow out of such division And Division as we have even now explicated being Locall Motion 't is evident that All operations among Bodies are either Local Motion or such as follow out of Local motion Which conclusion however unexpected and at first hearing appearing a Paradox will nevertheless by the ensuing work receive such evidence as it it cannot be doubted of and that not only by force of argumentation and by necessity of notions as is already reduced but also by experience and declaratiosns of particulars as they shall occur But now to apply what we have said to our proposed subject 't is obvious to every
man that seeing the Divider is the agent in division and in Local motion and dense bodies are by their nature dividers the Earth must in that regard be the most active among the Elements since it is the most dense of them all But this seems to be against the Common judgment of all the searchers of nature who unamimously agree that Fire is the most active Element As also it seems to impugne what we our selves have determin'd when we said there were two active qualities heat and cold whereof the first was in its greatest excess in Fire and the latter in water To reconcile these we are to consider that the action of Cold in its greatest height is composed of two parts the one is a kind of pressing and the other is penetration which requires applicability Of which two the former arises out of density but the latter out of moderation of density as I have declared in the precedent Chapter Wherefore the former will exceed more in Earth though the whole be more eminent in Water For though considering only the force of moving which is a a more simple and abstracted notion then the determination and particularization of the Elements and is precedent to it therein Earth hath a precedency over water yet taking the action as it is determin'd to be the action of a particular Element and as it concurs to the composition or dissolution of mixed bodies in that consideration which is the chief work of Elements and requires an intime application of the Agents Water hath the principality and excess over Earth As for Fire it is more active then either of them as will appear clearly if we consider how when Fire is applyed to fewel and the violence of blowing is added to its own motion it incorporates it self with the fewel and in a small time converts a great part of it into its own nature and shatters the rest into smoak and ashes All which proceeds from the exceeding smallness and dryness of the parts of fire which being moved with violence against the fewel and thronging in multitudes upon it easily pierce the porous substance of it like so many extreme sharp Needles And that the force of Fire is as great and greater then of Earth we may gather out of our former discourse where having resolved that density is the virtue by which a body is moved and cuts the medium and again considering that celerity of motion is a kind of density as we shall by and by declare 't is evident that since blowing must of necessity press violently and with a rapid motion the parts of fire against the fewel and so condense them exceedingly there both by their celerity by bringing very many parts together there it must needs also give them activity and vertue to pierce the body they are beaten against New that Celerity is a kind of Density will appear by comparing their natures For if we consider that a dense body may be dilated so as to possess and fill the place of a rare body that exceeded it in bigness and by that dilatation may be divided into as many and as great parts as the rare body was divisible into we may conceive that the substance of those parts was by a secret power of nature folded up in that little extension in which it was before And even so if we reflect upon two Rivers of equal channels and depths whereof the one goes swifter then the other and determine a certain length of each channel and a common measure of Time we shall see that in the same measure of time there passes a greater bulk of water in the designed part of the channel of the swifter stream then in the designed part of the flower though those parts be equal Nor imports it that in Velocity we take a part of time whereas in Density it seems that an instant is sufficient and consequently there would be no proportion between them For knowing Philosophers all agree that there are no Instants in time and that the apprehension of them proceeds meerly from the manner of our understanding And as for parts in time there cannot be assumed any so little in which the comparison is not true and so in this regard it is absolutely good And if the Reader have difficulty at the disparity of the things which are pressed together in Density and in Celerity for that in Density there is only Substance in Celerity there is also Quantity crowded up with the substence he will soon receive satisfaction when he shall consider that this disparity is to the advantage of what we say and makes the nature of density more perfect in celerity and consequently more powerful in fire then in earth Besides if there were no disparity it would be a distinct species of density but the very same By what we have spoken above it appears how fire gets into fewel now let us consider how it comes out for the activity of that fierce body will not let it lie still and rest as long as it has so many enemies round about it to rouse it up We see then that as soon as it has incoporated it self with the fewel and is grown master of it by introducing into it so many of its own parts like so many Souldiers into an Enemies Town they break out again on every side with as much violence as they came in For by reason of the former resistance of the fewel their continual streaming of new parts upon it and one overtaking another there where their journey was stop'd all which is increas'd by the blowing doth so exceedingly condense them into a narrower room then their nature effects that as soon as they get liberty and grow masters of the fewel which at the first was their prison they enlarge their place and consequently come out and flie abroad ever aiming right forwards from the point where they begin their journey for the violence wherewith they seek to extend themselves into a larger room when they have liberty to do so will admit no motion but the shortest which is by a straight line So that if in our phantasie we frame an image of a round body all of fire we must withall presently conceive that the flame proceeding from it would diffuse it self every way indifferently in straight lines so that the source serving for the Center there would be round about it an huge Sphere and of fire and light unless some accidental and extern cause should determine its motion more to one part then to another Which compass because it is round and has the figure of a Sphere is by Philosophers term'd the Sphere of its activity So that it is evident the most simple and primary motition of fire is a flux in a direct line from the center of it to its circumference taking the fewel for its center as also that when 't is beaten against a harder body it may be able to destroy it though that
is The better to apprehend how much this faint resemblance of flame upon the paper maketh for our purpose let us turn the leaf and imagine in our thoughts after what fashion that fire which is in the flame of a little candle would appear to us if it were dilated and stretch'd out to the utmost extent that excess of rarity can bring it to Suppose that so much flame as would fill a cone of two inches height and half an inch Diameter should suffer so great an expansion as to replenish with his light body a large chamber and then what can we imagine it would seem to be How would the continual driving it into a thinner substance as it streams in a perpetual flood from the flame seem to play upon the paper And then judg whether it be likely to be a body or no when our discourse suggests to us that if it be a body those very appearances must follow which our eyes give us evidence are so in effect If gold beaten into so airy a thinness as we see gilders use remains still Gold notwithstanding the wonderfull expansion of it why shall we not allow that fire dilated to its utmost period shall still remain fire though extreamly rarified beyond what it was We know that fire is the rarest and the subtilest substance that nature hath made among bodies and we know likewise that it is ingendred by the destroying and feeding upon some other more grosse body let us then calculate when the oyl or tallow or wax of a candle or the bulk of a faggot or billet is dilated and rarified to the degree of fire how vast a place must it take up To this let us add what Aristotle teaches us that fire is not like a standing pool which continues full with the same water and as it has no waste so has it no supply but it is a fluent and brook-like current Which also we may learn out of the perpetual nutriment it requires for a new part of fewel being converted into a new part of fire as we may observe in the little atomes of Oyl or melted wax that continually ascend apace up the wieke of a burning candle or lamp of necessity the former must be gone to make room for the latter and so a new part of the river is continually flowing Now then this perpetual flux of fire being made of a grosse body that so rarified will take up such a vast room if it die not at the instant of its birth but have some time to subsist be it never so short it must needs run some distance from the fountain whence it springs Which if it do you need not wonder that there should be so great an extent of fire as is requisite to fill all that space which light replenishes nor that it should be still supplyed with new as fast as the cold of the aire kills it For considering that flame is a much grosser substance then grosse fire by reason of the mixture with it of that viscous oyly matter which being drawn out of the wood and candle serves for fewel to the fire and is by little and little converted into it and withal reflecting on the nature and motion of fire which is to dilate it self extreamly and to fly all about from the center to the circumference you cannot choose but conceive that the pure fire strugling to break away from the oyly fewel which is still turning into new fire doth at length free his wings from that birdlime and then flies abroad with extream swiftness swels and dilates it self to a huge bulk now that it has gotten liberty and so fills a vast room but remains still fire till it die Which it no sooner doth but it is still supply'd with new streams of it that are continually strain'd as it were squees'd out of the thick flame which imprison'd and kept it within it till growing fuller of fire then it could contain by reason of the continual attenuating the oyly parts of it and converting them into fire it gives liberty to those parts of fire that are next the superficies to fly whither their nature will carry them And thus discourse would inform a Blind man after he has well reflected on the nature of fire how it must needs fill a mighty extent of place though it have but a narrow beginning at its spring head and that there by reason of the condensation of it and mixture with a grosser body it must needs burn other bodies but that when it is freed from such mixture and suffers an extream expansion it cannot have force to burn but may have means to express it self to be there present by some operation of it upon some body that is refin'd and subtilized enough to perceive it And this operation a seeing man will tell you is done upon his eyes whose fitness to receive impression from so subtile an Agent Anatomists will teach you And I remember how a blind Schoolmaster that I kept in my house to teach my children who had extream subtile spirits and a great tenderness through his whole body and met with few distractions to hinder him from observing any impression never so nicely made upon him used often to tell me that he felt it very perceptibly in several parts of his body but especially in his brain But to settle us more firmly in the perswasion of light 's being a body and consequently fire let us consider that the properties of a body are perpetually incident to light look what rules a ball will keep in its rebounds the same doth light in its reflections and the same demonstration alike convinces the one and the other Besides light is broken like a body as when 't is snapped in pieces by a tougher body it is gather'd together in a little room by looking or burning glasses as water is by ordering the gutters of a house so as to bring into one cistern all that rains dispersedly upon the whole roof It is sever'd and dispers'd by other glasses and is to be wrought upon and cast hither and thither at pleasure all by the rule of other bodies And what is done in light the same will likewise be done in heat in cold in wind and in sound And the very same instruments that are made for light will work their effects in all these others if they be duly managed So that certainly were it not for the authority of Aristotle and his learned followers that presses us on the one side and for the seemingness of those reasons we have already mention'd which perswades us on the other side our very eyes would carry us by stream into this consent that light is no other thing but the nature and substance of fire spread far and wide and freed from the mixture of all other gross bodies Which will appear yet more evident in the solutions of the oppositions we have brought against our own opinion for in them there will
conceive let us go on to the fourth which requires that we satisfie their inquisition who ask what becomes of that vast body of shining light if it be a body that fills all the distance between heaven and earth and vanishes in a moment assoon as a cloud or the Moon interposes it self between the Sun and us or that the Sun quits our Hemisphere No sign at all remains of it after its extinction as doth of all other substances whose destruction is the birth of some new thing Whither then is it flown we may be perswaded that a mist is a corporeal substance because it turns to drops of water upon the twigs that it invirons and so we might believe light to be fire if after the burning of it out we found any ashes remaing but experience assures us that after it is extinguished it leaves not the least vestigium behind it of having been there Now before we answer this objection we will intreat our Adversary to call to mind how we have in our solution of the former declared and proved that the light which for example shines from a candle is no more then the flame is from whence it springs the one being condensed and the other dilated and that the flame is in a perpetual flux of consumption about the circumference and of restauration at the center where it sucks in the fewell and then we will enquire of him what becomes of the bodie of flame which so continually dies and is renewed and leaves no remainder behind it as well as he doth of us what becomes of our body of light which in like manner is alwaies dying and alwaies springing fresh And when he hath well considered it he will find that one answer will serve for both Which is That as the fire streams out from the fountain of it and growes more subtile by its dilatation it sinks the more easily into those bodies it meets withall the first of which and that environs it round about is aire With air then it mingles and incorporates it self and by consequence with the other little bodies that are mingled with the aire and in them it receives the changes which nature works by which it may be turn'd into the other Elements if there be occasion or be still conserv'd in bodies that require heat Upon this occasion I remember a rare experiment that a Noble-Man of much sincerity and a singular friend of mine told me he had seen which was That by meanes of glasses made in a very particular manner and artificially placed one by another he had seen the Sun-beams gather'd together and precipitated down into a brownish or purplish red powder There could be no fallacy in this operation for nothing whatever was in the glasses when they were placed and disposed for this intent and it must be in the hot time of the year else the effect would not follow And of this Magistry he could gather some dayes near two ounces in a day And it was of a strange volative nature and would pierce and imprint his spiritual quality into gold it self the heaviest and most fixed body we converse withall in a very short time If this be plainly so without any mistaking then mens eyes and hands may tell them what becomes of light when it dies if a great deal of it were swept together But from what cause soever this experience had its effect our reason may be satisfied with what we have said above for I confesse for my part I beleeve the appearing body might be something that came along with the Sun-beams and was gather'd by them but not ther pure substance Some peradventure will object those lamps which both ancient and modern writers have reported to have been found in Tombes and Urns long time before closed up from mens repair to them to supply them with new fewel and therefore they believe such fires to feed upon nothing and consequently to be inconsumptible and perpetual Which if they be then our doctrine that will have light to be nothing but the body of fire perpetually flowing from his center and perpetual dying cannot be sound for in time such fires would necessarily spend themselves in light although light be so subtile a substance that an exceeding little quantity of fewel may be dilated into a vast quantity of light However there would be some consumption which how imperceptible soever in a short time yet after a multitude of revolutions of years must needs discover it self To this I answer That for the most part the witnesses who testifie originally the stories of these lights are such as a rational man cannot expect from them that exactness or nicitie of observation which is requisite for our purpose For they are usually gross labouring people who as they dig the ground for other intentions Stumble upon these Lamps by chance before they are aware and commonly they break them in the finding and imagine they see a glimpse of light which vanishes before they can in a manner take notice of it and is peradventure but the glistering of the broken glass or glazed pot which reflects the outward light assoon as by rummaging in the ground and discovering the Glass the light strikes upon it in such manner as sometimes a Diamond by a certain incountring of light in a dusky place may in the first twinkling of the motion seem to sparkle like fire And afterwards when they shew their broken Lamp and tell their tale to some man of a pitch of wit above them who is curious to inform himself of all the circumstances that may concern such lights they strain their memory to answer him satisfactorily unto all his demands and thus for his sake they perswade themselves to remember what they never saw and he again on his side is willing to help out the story a little And so after a while a very formal and particular relation is made of it As happens in like sort in reporting of all strange and unusual things when even those that in their nature abhor from lying are naturally apt to strain a little and fashion up in a handsome mould and almost to perswade themselves they saw more then they did so innate it is to every man to desire the having of some preeminence beyond his neighbours be it but in pretending to have seen something which they have not Therefore before I engage my self in giving any particular answer to this objection of pretended inconsumptible lights I would gladly see the effect certainly averred and undoubtedly proved For the testemonies which Fortunius Licetus produces who has been very diligent in gathering them and very sub 〈◊〉 in discoursing upon them and as the exactest Author that has written upon this subject do not seem to me to make that certainty which is required for the establishing of a ground in Philosophy Nevertheless if there be any certain experience in this particular I should think there might be some Art by circulation
of fewel to maintain the same light for a great company of years But I should not easily be perswaded that either flame or light could be made without any manner of consuming the body which serves them for fewel CHAP. VIII An Answer to three other Objectious formerly proposed against Light being a Substance HAving thus defended our selves from their Objections who would not allow light to be fire and having satisfied their inquisition who would know what becomes of it when it dyes if it be a body we will now apply our selves to answer their difficulties who will not let it pass for a body because it is in the same place with another body as when the Sun-beams enlighten all the air and when the several lights of two distinct Candles are both of them every where in the same room Which is the substance of the second main objection This of the justling of the aire is easily answered thus that the aire being a very divisible body doth without resistance yield as much place as is requisite for light And that light though our eyes judge it diffused every where yet is not truly in every point or atome of air but to make us see it every where it suffices that it be in every part of the air which is as big as the black or sight of our eye so that we cannot set our eye in any position where it receives not impressions of light In the same manner as Perfumes which though they be so gross bodies that they may be sensibly wasted by the wind yet â—o fill the air that we can put our nose in no part of the room where a perfume is burned but we shall smell it And the like is of mists as also of the sprouted water to make a perfume which we mention'd above But because pure discourses in such small thrids as these 〈◊〉 but weakly bind such Readers as are not accustom'd to them and I would if possible render this Treatise intelligible to every rational man how ever little vers'd in Scholastick learning among whom I expect it will have a fairer passage then among those that are already deeply imbued with other principles let us try if we can herein inform our selves by our sense and bring our eyes for witness of what we say He then that is desirous to satisfie himself in this particular may put himself in a dark room through which the Sun sends his beams by a cranie or little hole in the wall and he will discover a multitude of little atomes flying about in that little stream of light which his eye cannot discern when he is environ'd on all sides with a full light Then let him examine whether or no there be light in the midst of those little bodies and his own reason will easily till him that if those bodies were as perspicuous as the air they would not reflect upon our eyes the beams by which we see them And therefore he will boldly conclude that at the least such parts of them as reflect light to us do not admit it nor let it sink into them Then let him consider the multitude of them and the little distance betwixt one another and how nevertheless they hinder not our sight but we have it free to discover all objects beyond them in what position soever we place our eye And when he thus perceives that these opacous bodies which are every where do not hinder the eye from judging light to have an equal plenary diffusion through the whole place that it irradiates he can have no difficulty to allow air that is diaphanous and more subtile far then they and consequently divisible into lesser atomes and having lesser pores gives less scope to our eyes to miss light then they do to be every where mingled with light though we see nothing but light and cannot discern any breach of it Especially when he shall adde to this consideration that the subtile body which thus fills the air is the most visible thing in the world and that whereby all other things are seen and that the air it mingles it self with is not at all visible by reason of the extreme diaphaneity of it and easie reception of the light in every pore of it without any resistance or reflection and that such is the nature of light as it easily drowns an obscure body if it be not too big and not onely such but even other light bodies for so we know as well the fixed Stars as the Planets are conceal'd from our sight by the nearness to the Sun neither the lightness of the one nor the bigness of the other prevailing against the darkning of an exuperant light and we have daily experience of the same in very pure chrystal glasses and in very clear water which though we cannot discern by our sight if they be certain positions nevertheless by experience we find that they reflect much light and consequently have great store of opacous parts And then he cannot choose but conclude that it is impossible but light should appear as it doth to be every where and to be one continued thing though his discourse withal assure him it is every where mingled with air And this very answer I think will draw with it by consequence the solution of the other part of the same objection which is of many lights joyning in the same place and the same is likewise concerning the images of colours every where crossing one another without hindrance But to raise this contemplation a strain higher let us consider how light being the most rare of all known bodies is of its own nature by reason of the divisibility that followeth rarity divisible into lesser parts then any other and particularly then flame which being mixed with smoke and other corpulency falls very short of light And this to the proportion in which it is more rare then the body 't is compared to Now a great Mathematician having devised how to measure the rarefaction of Gun-powder into flame found the Diameter fifty times increased and so concluded that the body of the flame was in proportion to the body of the Gun-powder it was made of as 125000. is to one Wherfore by the immediately proceeding consequence we find that 125000 parts of flame may be couched in the room of one least part of gunpowder and peradventure many more considering how porous a body Gun-powder is Which being admitted 't is evident that although light were as gross as the flame of Gun-powder and Gun-powder were as solid as gold yet there might pass 125000. rayes of light in the space wherin one least part of Gun-powder might be contained which space would be absolutely invisible to us and be contained many times in the bigness of the sight of a mans eye Out of which we may gather what an infinity of objects may seem to us to cross themselvs in the same indivisible place and yet may have room sufficient for every one
to pass his way without hindring his fellow Wherfore seeing that one single light could not send rayes enough to fil every little space of aire that is capable of light and the less the further it is from the flame 't is obvious enough to conceive how in the space where the air is there is capacity for the rays of many candles Which being well sum'd up will take away the great admiration how the beams of light though they be corporeall can in such great multitudes without hindering one another enter into bodies and come to our eye and will shew that 't is the narrowness of our capacities and not the defect of nature which makes these difficulties seem so great For she hath sufficiently provided for all these subtile operations of fire as also for the entrance of it into glass and into all other solid bodies that are Diaphanous upon which was grounded the last instance the second objection pressed for all such bodies being constituted by the operation of fire which is alwaies in motion there must needs be ways left for it both to enter in and to evaporate out And this is most evident in glass which being wrought by an extreme violent fire and swelling with it as water and other things do by the mixture of fire must necessarily have great store fire in it self whiles it is boyling as we see by its being red hot And hence it is that the workmen are forced to let it cool by degrees in such relentings of fire as they call their nealing heats lest it should shiver in pieces by a violent succeeding of air in the room of the fire for that being of greater parts then the fire would strain the pore of the glass too suddenly and break it all in pieces to get ingressions whereas in those nealing heats the air being rarer lesser parts of it succeed to the fire and leisurely stretch the pores without hurt And therefore we need not wonder that light passes so easily through glass and much less that it gets through other bodies seeing the experience of Alchymists assures us 't is hard to find any other body so impenitrable as glass But now to come to the answer of the first and in appearance most powerful objection against the corporeity of light which urges that its motion is perform'd in an instant and therefore cannot belong to what is material and cloth'd with quantity We will endeavour to shew how unable the sense is to judge of sundry sorts of motions of Bodies and how grosly it is mistaken in them And then when it shall appear that the motion of light must necessarily be harder to be observed then those others I conceive all that is rais'd against our opinion by so incompetent a judge will fall flat to the ground First then let me put the Reader in mind how if ever he mark'd children when they play with firesticks they move and whirle them round so fast that the motion will cosen their eyes and represent an entire circle of Fire to them and were it somewhat distant in a dark night that one play'd so with a lighted Torck it would appear a constant Wheele of fire without any discerning of motion in it And then let him consider how slow a motion that is in respect of what 't is possible a body may participate of and he may safely conclude that 't is no wonder though the motion of light be not descried and that indeed no argument can be made from thence to prove that light is not a body But let us examine this consideration a little further and compare it to the motion of the earth or heavens Let the appearing circle of the fire be some three foot Diameter and the time of one entire circulation of it be the sixtieth part of a minute of which minutes there are 60. in an hour so that in a whole day there will but be 86400. of these parts of time Now the Diameter of the wheel of fire being but of three foot the whole quantity of space that it moves in that atome of time will be at the most ten foot which is three paces and a foot of which parts there are near eleven millions in the compass of the earth so that if the earth be moved round in 24. hours it must go near 130. times as fast as the Boy 's stick which by its swift motion deceives our eye But if we allow the Sun the Moon and the fixed Stars to move how extreme swift must their flight be and how imperceptible would their motion be in such a compass as our sight would reach to And this being certain that whether the earth or they move the appearances to us are the same 't is evident that as now they cannot be perceiv'd to move as peradventure they do not so it would be the very same in shew to us although they did move If the Sun were near us and gallop'd at that rate surely we could not distinguish between the beginning and ending of his race but there would appear one permanent Line of light from East to West without any motion at all as the Torch seems to make with so much a slower motion one permanent immoveable wheel of fire But contrary to this effect we see that the Sun and Stars by onely being removed further from our eyes do cosen our sight so grossely that we cannot discern them to be moved at all One would imagine that so rapid and swift a motion should be perceiv'd in some sort or other which whether it be in the earth or in them is all one to this purpose Either we should see them change their places whiles we look upon them as Arrows and Birds do when they fly in the Aire or else they should make a stream of light bigger then themselvs as the Torch doth But none of all this happens Let us gaze upon them so long and so attentively that our eyes be dazled with looking and all that while they seem to stand immovable and our eyes can give us no account of their journey till it be ended They discern it not while it is in doing So that if we consult with no better counsellour then them we may wonder to see that body at night setting in the West which in the morning we beheld rising in the East But that which seems to be yet more strange is that these bodies move cross us and nevertheless are not perceiv'd to have any motion at all Consider then how much easier it is for a thing that moves towards us to be with us before we are aware A nimble Fencer will put in a thrust so quick that the â—oil will be in your bosome when you thought it a yard off because in the same moment you saw his point so far distant and could not discerne it to move towards you till you felt the rude salutation it gave you If then you will compare the body of light with
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
downwards Nor need we fear lest the littlenessof the agents or the feebleness of their stroaks should not be sufficient to work this effect since there is no resistance in the body it self and the air is continually cut in pieces by the Sun-beams and by the motions of little bodies so that the adhesion to air of the body to be moved will be no hind'rance to this motion especially considering the perpetual new percussions and the multitude of them and how no force is so little but that with time and multiplication it will overcome any resistance But if any man desires to look on as it were at one view the whole chain of this doctrine of Gravity let him turn the first cast of his eyes on what we have said of fire when we explicated the nature of it To wit that it begins from a little source and by extreme multiplication and rarefaction extends it self into a great sphere And then hee 's perceive the reason why light is darted from the body of the Sun with that incredible celerity wherewith its beams fly to visit the remotest parts of the world and how of necessity it gives motion to all circumstant bodies since it is violently thrust forward by so extreme rarefaction and the further it goes is still the more rarified and dilated Next let him reflect how infinitely the quickness of lights motion prevents the motion of a moist body such an one as air is and then he wil plainly see that the first motion which light is able to give the air must needs be a swelling of that moist element perpendicularly round about the earth For the ray descendent and the ray reflectent flying with so great a speed that the air between them cannot take a formal pley any way before the beams of light be on both sides of it it followes that according to the nature of humide things it must first only swell for that is the beginning of motion in them when heat enters into and works on them And thus he may confidently resolve himself that the first motion which light causes in the air will be a swelling of it between the two rays towards the middle of them That is perpendicularly from the surface of the earth And out of this he will likewise plainly see that if there be any other little dense bodies floating in the air they must likewise mount a little through this swelling and rising of the air But that mounting will be no more then the immediate parts of the air themselvs move Because this motion is not by way of impulse or stroke that the air gives those denser bodies but by way of containing them in it and carrying them with it so that it gives them no more celerity then to make them go with it self and as parts of it self Then let him consider that light or fire by much beating upon the earth divides some little parts of it from others wherof if any become so small and tractable as not to exceed the strength which the rays have to manage them the returning rays will at their going back carry away with or drive before them such little atomes as they made or met with and so fill the air with little bodies cut out of the earth After this let him consider that when light caries up an atome with it the light and the atome stick together and make one ascending body in such sort as when an empty dish lies upon the water the air in the dish makes one descendent body together with the dish it self so that the density of the whole body of air and dish which in this case are but as one body is to be esteem'd according to the density of the two parts one of them being allay'd by the other as if the whole where thrughout of such a proportion of density as would arise out of the composition and kneading together the several densities of those two parts Now then when these little compounded bodies of light and earth are carryed up to a determinate height the parts of fire or light by little and little break away from them and therby the bulk of the part which is left becoms of a different degree of density quantity for quantity from the bulk of the entire atome when light was part of it and consequently it is denser then it was Besides let him consider that when these bodies ascend they go from a narrow room to a large one that is from the centrewards to the circumference but when they come down again they go from a larger part to a narrower Whence it followes that as they descend they draw closer and closer together and by consequence are subject to meet and fall in one with another and therby to increase their bulk and become more powerful in density not only by the loss of their fire but also by the encrease of their quantity And so 't is evident that they are denser coming down then going up Lastly let him consider that those atoms which went up first and are parted from their volative companions of fire or light must begin to come down apace when other new atoms which still have their light incorporated with them ascend to where they are and go beyond them by reason of their greater levity And as the latter atoms come up with a violence and great celerity so must the first go down with a smart impulse and by consequence being more dense then the air in which they are carryed must of necessity cut their way through that liquid and rare Medium and go the next way to supply the defect and room of the atoms which ascend that is perpendicularly to the earth and give the like motion to any body they find in their way if it be susceptible of such a motion Which 't is evident that all bodies are unless they be strucken by some contrary impulse For since a bodies being in a place is nothing else but the continuity of its outside to the inside of the body that contains it and is its place it can have no other repugnance to local motion which is nothing else but a successive changing of place besides this continuity Now the nature of density being the power of dividing and every least power having some force efficacy as we have shew'd above it follows that the stroke of every atome either descending or ascending will work somthing upon any body though never so big it chances to incounter with and strike upon in its way unless there be as strong an impulse the contrary way to oppose it But it being determin'd that the descending atoms are denser then those that ascend it follows that the descending ones will prevail And consequently all dense bodies must necessarily tend downwards to the center which is to be heavy if some other more dense body do not hinder them Out of this discourse we may conclude that there is no such thing among bodies
as positive gravity or levity but that their course upwards or downwards happens to them by the order of nature which by outward causes gives them an impulse one of these wayes without which they would rest quietly wherever they are as being of themselvs indifferent to any motion But because our words express our notions and they are fram'd according to what appears to us when we observe any body to descend constantly towards our earth we call it heavie and if it move contrarywise we call it light But we must take heed of considering such gravity and levity as if they were Entities that work such effects since upon examination it appears that these words are but short expressions of the effects themselves the causes whereof the vulgar of mankind who impose names to things do not consider but leave that work to Philosophers to examine whiles they onely observe what they see done and agree upon words to express that Which words neither will in all circumstances always agree to the same thing for as cork descends in aire and ascends in water so also will any other body descend if it lights among others more rare then it self and will ascend if it lights among others that are more dense then it And we term Bodies light and heavy only according to the course which we usually see them take Now proceeding further on and considering how there are various degrees of density or gravity it were irrational to conceive that all bodies should descend at the same rate and keep equal pace with one another in their journey downwards For as two knives whereof one hath a keener edge then the other being press'd with equal strength into like yielding matter the sharper will cut deeper then the other so if of two bodies one be more dense then the others that which is so will cut the air more powerfully and descend faster then the other for in this case density may be compared to the kniefs edge since in it consists the power of dividing as we have heretofore determin'd And therefore the pressing them downwards by the descending atomes being equal in both or peradventure greater in the more dense body as anon we shall have occasion to touch and there being no other cause to determine them that way the effect of division must be the greater where the divider is the more powerful Which the more dense body is and therefore cuts more strongly through the resistance of the air and consequently passes more swiftly that way 't is determin'd to move I do not mean that the velocities of their descent shall be in the same proportion to one another as their densities are for besides their density those other considerations which we have discours'd of above when we examin'd the causes of velocity in motion must likewise be ballanced And out of the comparisons of all them not out of the consideration of any one alone results the differences of their velocities nor that neither but in as much as concerns the consideration of the moveables for to make the calculation exact the Medium must likewise be considered as by and by we shall declare For since the motion depends of all them together though there should be difference between the moveables in regard of one only and that the rest were equal yet the proportion of the difference of their motions must not follow the proportion of their difference in that one regard because their difference consider'd single in that regard will have one proportion and with the addition of the other considerations though alike in both to their difference in this they will have another As for example reckon the density of one moveable to be double the density of another moveable so that in that regard it has two degrees of power to descend whereas the other has but one suppose then the other causes of thier descent to be alike in both and reckon them all three and then joyn these three to the one which is caused by the density in one of the moveables as likewise to the two which is caused by the density in the other moveable and you will find that thus altogether their difference of power to descend is no longer in a double proportion as it would be if nothing but their density were considered but is in the proportion of five to four But after we have consider'd all that concerns the moveables we are then to cast an eye upon the Medium they are to move in and we shall find the addition of that decreases the proportion of their difference exceedingly more according to the cessibility of the Medium Which if it be Air the great disproportion of its weight to the weight of those bodies which men use to take in making experiences of their descent in that yeelding Medium will cause their difference of velocity in descending to be hardly perceptible Even as the difference of a sharp or dull knife which is easily perceiv'd in cutting of flesh or bread is not to be distinguish'd in dividing of water or oyl And likewise in Weights a pound and a scruple will bear down a dram in no sensible proportion of velocity more then a pound alone would do and yet put a pound in that scale in stead of the dram and then the difference of the scruple will be very notable So then those bodies whose difference of descending in water is very sensible because of the greater proportion of weight in water to the bodies that descend in it will yield no sensible difference of velocity when they descend in air by reason of the great disproportion of weight between air and the bodies that descend in it The reason of this will clearly shew it self in abstracted proportions Thus Suppose air to have one degree of density and water to have 400 then let the moveable A. have 410 degrees of density and the moveable B. have 500. Now compare their motion to one another in the several mediums of air and water The exuperance of the density of A. to water is 10 degrees but the exuperance of B. to the same water is 100 degrees so that B. must have in water swifter then A in the proportion of 103 to ten that is of 10 to one Then let us compare the exuperance of the two moveables over air A is 409 times more dense then air but B is 499 times more dense then it by which account the motion of B. must be in that medium swifter then the motion of A in the proportion of 499 to 409 that is about 50 to 41 which to avoid fractions we may account as 10 to 8. But in water they exceed one another as 10 to one so that their difference of velocity must be scarce perceptible in air in respect of what it is in water Out of all which discourse I only infer in common that a greater velocity in motion will follow the greater density of the moveable without determining
notable degree as for example to water makes then a great difference of a heavy bodies gravitation in it and accordingly we see a great difference between heavy bodies descending in water and in air though between two kinds of air none is to be observ'd their difference is so smal in respect of the density of the body that descends in them And therfore since an assured and certain difference in circumstances makes no sensible inequality in the affect we cannot expect any from such circumstances as we may reasonably doubt whether there be any inequality among them or no. Besides that if in any of the proposed cases a heavy body should gravitate more and be heavier one time than another yet by weighing it we could not discern it since the counterpoise which is to determine its weight must likewise be in the same proportion heavier then it was And besides weighing no other means remains to discover its greater graviation but to compare it to Time in its descent and I believe that in all such distances as we can try it in its inequalities will be no whit less difficult to be observ'd that way then any other Lastly to bend our discourse particularly to that instance of the objection where it is conceiv'd that if gravity or descending downwards of bodies proceeded from atoms striking on them as they move downwards it would follow that a stone or other dense body lying under shelter of a thick hard and impenetrable adamantine rock would have no impulse downwards and consequently would not weigh there We may note that no body whatever compacted by physical causes and agents can be so dense and imporous but that such atoms as these we speak of must be in them and in every part of them and every where pass through and through them as water doth through a sieve or through a spunge and this universal maxime must extend as far as the Sun or any other heat communicating with the Sun reaches and is found The reason whereof is because these atoms are no other thing but such extreme little bodies as are resolved by heat out of the main stock of those massie bodies upon which the Sun and heat do work Now then it being certain out of what we have heretofore said that all mixt bodies have their temper and consistence and generation from the mingling of fire with the rest of the Elements that compose them and from the concoction or digestion which fire makes in those bodies 't is evident that no mixt body whatever nor any sensible part of a mixt body can be void of pores capable of such atoms or be without such atoms passing through those pores which atoms by mediation of the air that likewise hath its share in such pores must have communication with the rest of the great sea of air and with the motions that pass in it And consequently in all and every sensible part of any such extreme dense and pretended inpenetrable body to the notice wherof we can arrive this percussion of atoms must be found and they will have no difficulty in running through nor by means of it in striking any other body lying under the shelter of it and thus both in from that hard body there must be stil an uninterrupted continuation of gravity or of descending towards the centre To which we may adde that the stone or dense body cannot lie so close to the rock that covers it but that some air must be between for if nothing were between they would be united and become one continued body and in that air which is a Creek of the great Ocean of air spread over the world that is every where bestrew'd with moving atoms and which is continually fed like a running stream with new air that drives on the air it overtakes no doubt but there are descending atoms as well as in all the rest of its main body and these descending atoms meeting with the stone must needs give some stroke upon it and that stroke be it never so little cannot chuse but work some effect in making the stone remove a little that way they go and that motion wherby the space is inlarg'd between the stone and the shelt'ring rock must draw in a greater quantity of air and atoms to strike upon it And thus by little and little the stone passes through all the degrees of tardity by which a descending body parts from rest which is by so much the more speedily done by how much the body is more eminent in density But this difference of time in regard of the atoms strokes only and abstracting from the bodies density will be insensible to us seeing as we have said no more is required of them but to give a determination downwards And out of this we clearly see the reason why the same atoms striking upon one body lying on the water make it sink and upon another they do not As for example if you lay upon the superficies of some water a piece of iron and a piece of cork of equal bigness and of the same figure the iron will be beaten down to the bottom and the cork will float at the top The reason wherof is the different proportions of the comparison of their densities with the density of water for as we have said the efficacy and force of descending is to be measured by that So then the strokes of the atoms being more efficatious upon water then upon cork because the density of water is greater then the density of cork considering the abundance of air that is harbor'd in the large pores of it it followes that the atoms will make the water go down more forcibly then they will cork But the density of iron exceeding the density of water the same strokes will make the iron descend faster then the water and consequently the iron must sink in the water and the cork will swim upon it And this same is the cause why if a piece of cork be held by force at the bottom of the water it will rise up to the top as soon as the violence is taken away that kept it down for the atoms strokes having more force on the water then on the cork they make the water sink and slide under it first a little thin plate of water and then another a little thicker and so by degrees more and more till it hath lifted the cork quite up to the top Fifthly it may be objected that these atoms do not descend always perpendicularly but somtimes slopingly and in that case if their strokes be the cause of dense bodies moving they should move sloping and not downward Now that these atoms descend somtimes slopingly is evident as when for example they meet with a stream of water or with a strong wind or even with any other little motion of the air such as carries feathers up and down hither and thither which must needs waft the atoms in some measure along
carried out of the force of that motion directly the contrary way till the force of gravity overcoming the velocity it must be brought back again to the perpendicular which being done likewise with velocity it must send it again towards the place from which it fell at the first And in this course of motion it must continue for a while every Undulation being weaker then other till at last it quite ceases by the course of nature setling the air in its due situation according to the natural causes that work upon it And in this very manner also is performed that Undulation we see in water when it is stir'd from the natural situation of its Spherical superficies Galileo hath noted that the time in which the Undulations are made which follow one another of their own accord is the same in every one of them and that as much time precisely is taken up in a pendants going a very short arch towards the end of its vibration as was in its going the greatest arch at the beginning of its motion The reason wherof seems strange to him and he thinks it an accident natural to the body out of its gravity and that this effect convinces it is not the air which moves such bodies Wheras in truth 't is clearly the air which causes this effect Because the air striving at each end where it is furthest from the force of the motion to quiet it self gets at every bout somwhat upon the space and so contracts that into a shorter arch That motion also which we call Refraction and is manifest to sense only in light though peradventure hereafter more diligent searchers of nature may likewise find in such other bodies as are called qualitie as in cold or heat c. is but a kind of Reflexion For there being certain bodies in which the passages are so well order'd with their resistences that all the parts of them seem to permit light passe through them and yet all seem to reflect it when light passes through such bodies it finds at the very entrance of them such resistences where it passes as serve it for a reflecting body and yet such a reflectent body as hinders not the passage through but only from being a staight line with the line incident Wherfore the light must needs take a ply as beaten from those parts towards a line drawn from the illuminant falling perpendicularly upon the resisting superficies and therfore is term'd by Mathematicians to be refracted or broken towards the perpendicular Now at the very going out again of the light the second superficies if it be parallel to the former must needs upon a contrary cause strike it the contrary way which is which is termed from the perpendicular But before we wade any deeper into this difficulty we cannot omit a word of the manner of explicating Refraction which Monsieur des Cartes uses so witty a one as I am sorry it wants success He therefore following the demonstration above given of Reflection supposes the superficies which a ball lights upon to be a thin linen cloth or some other such matter as will break cleanly by the force of the ball striking smartly upon it And because that superficies resists only one way therfore he infers that the velocity of the ball is lessen'd only one way and not the other so that the velocity of its motion that way in which it finds no resistance must be after the balls passage through the linnen in a greater proportion to the velocity which it has the other way were it finds resistance then it was before And therfore the ball will in less time arrive to its period on the one side then on the other and consequently lean towards that side to which the course wherin it findes no opposition carries it Which to shew how it is contrary to his own principle Let us conceive the cloth CE to be of some thickness and so draw the line OP to determine that thickness And let us make from B upon AL another Parallelogram like the Parallelogram AL whose Diameter shall be BQ And it must necessarily follow that the motion from B to Q if there were no resistance were in the same proportion as from A to B. But the proportion of the motion as from A to B is the proportion of CB to CA that is it goes in the same time faster towards D then towards M in proportion which CB hath to CA. By which account the resistance it has in the way towards D must also be greater then the resistance it has in the towards M in the proportion which CB has to CA and therfore the more tardicy must be in the way to D and not in the way to M and consequently the declination must be from E wards and to M wards For where there is most resistance that way likewise must the tardity be greatest and the declination must be from that way but which way the thickness to be passed in the same time is most that way the resistance is greatest and the thickness is clearly greater towards E then towards M therfore the resistance must be greatest towards E and consequently the declination from the line BL must be towards M and not towards E. But the truth is in his Doctrine the ball would go in a straight line as if there were no resistance unless peradventure towards the contrary side of the cloth at which it goes out into the free air For as the resistance of the cloth is greater in the way towards D then in the way towards M because it passes a longer line in the same time as also it did formerly in the air so likewise is the force that moves it that way greater then the force which moves it the other And therfore the same proportions that were in the motion before it came to the resisting passage will remain also in it at least till coming near the side at which it goes out the resistance be weakned by the thinness of the resistent there which because it must needs happen on the side that has least thickness the ball must consequently turn the other way where it findes greatest yielding and so at its getting out into the free air it will bend from the greater resistance in such manner as we have said above Neither do the examples brought by Monsieur des Cartes and others in the maintenance of this Doctrine any thing avail them for when a Canon Bullet shot into a River hurts the people on the other side 't is not caused by refraction but by reflection as Monsir des Cartes himself acknowledges and therfor has no force to prove any thing in refraction whose Laws are divers from those of pure reflection And the same answer servs against the instance of a Musket bullot shot at a mark under water which perpetually lights higher then the mark though exactly just aim'd at For we knowing that it is the nature of
water by sinking in one place to rise round about it must of necessity follow that the bullet which in entring has press'd down the first parts of the water has withal therby put others further off in a motion of rising and therfore the bullet in its going on must meet with some water swelling upwards and from it receive a ply that way which cannot fail of carrying it above the mark it was level'd at And so we see this effect proceeds from reflection or the bounding of the water and not from refraction Besides that it may justly be suspected the shooter took his aim too high by reason of the marks appearing in the water higher than in truth it is unless such false aiming were duly prevented Neither is Monsir des Cartes his excuse to be admitted when he saies that light goes otherwise than a ball would do because in a glass or water the etherial substance which he surposes to run through all bodies is more efficaciously moved than in air and thersore light must go faster in the glass than in the air and so turn on that side of the straight line which is contrary to the side that the ball takes because the ball goes not so swiftly For not to dispute the verity of this proposition the effect he pretends is impossible for if the etherial suhstance in the air before the glass be flowly moved the motion of which he calls light 't is impossible that the etherial substance in the glass or in the water should be more smartly moved than it Well it may be less but without all doubt the impulse of the etherial substance in the Glass cannot be greater than its adequate cause which is the motion of the other parts that are in the air precedent to glass Again after it is pass'd the glass it should return to be a straight line with the line that it made in the air precedent to the glass in the subsequent air must take off just as much and no more as the glas did add the contrary wherof experience shews us Thirdly in this explication it would always go one way in the air and another way in the glass wheras all experience testifies that in a glass convex on both sides it still goes in the air after its going out to the same side as it did in the glass but more And the like happens in glasses on both sides concave Wherfore 't is evident that 't is the snperficies of the Glass that is the worker on both sides and not the substance of the air on one side and of the glass on the other And lastly his answer no way solvs our objection which proves that the resistance both ways is proportionate to the force that moves and by consequence that the thing moved must go straight As we may imagine would happen if a bullet were shot stoping through a green mud wall in which there were many round sticks so thin set that the bullet might pass with ease through them for as long as the bullet touched none of them which express his case it would go straight but if it touch'd any which resembles ours as by and by will apperar it would glance according to the quality of the touch and move from the stick in another line Some peradventure may answer for Monsieur des Cartes that this subtile body which he supposes to run through all things is stiff and no ways pliable But that is so repugnant to the nature of rarity and so many insuperable inconveniences follow out of it as I cannot imagin he will own it and therfore I will not spend any time in replying therto We must therfore seek some other cause of the refraction of light which is made at the entrance of it into a Diaphanous body Which is plainly as we said before because the ray striking against the inside of a body it cannot penetrate turns by reflection towards that side on which the illuminant stands and if it findes clear passage through the whole resistent it follows the course it first takes if not then 't is lost by many reflections to and fro But because crooked surfaces may have many irregulalities it will not be amiss to give a rule by which all of them may be brought to a certainty And this it is that Reflections from crooked superficieses are equal to the reflections that are made from such plain superficieses as are tangents to the crooked ones in that point from whence the reflections are made Which Principle the Masters of Opticks take out of a Mathematecal supposition of the Unity of the reflecting point in both the surfaces the crooked and the plain But we take it out of the insensibility of the difference of so little a part in the two different surfaces as serves to reflect a ray of light For where the difference is insensible in the causes there likewise the difference is so little in the effects as sense cannot judge of them which is as much as is requisite to our purpose Now since in the Mathematical supposition the point where the reflection is made is indifferent to both the surfaces it follows that it imports not whether superficies you take to know the quality of reflection by This principle then being setled that the reflection must follow the nature of the tangent surfaces and it being proved that in plain surfaces it will happen as we have explicated it follows that in any crooked supersicies of what Figure soever the same also will happen Now seeing we have formerly declared that refractions are but a certain kind of reflexions what we have said here of reflections may be apply'd to refractions But there remains yet untouch'd one affection more of refractions which is that some Diaphanous bodies in their inward parts reflect more than others which is that we call refraction as experience shews us Concerning which effect we are to consider that Diaphanous bodies may in their composition have two differences for some are composed of greater parts and greater pores others of lesser parts and lesser pores 'T is true there may be other combinations of pores and parts yet by these two the rest may be esteem'd As for the first combination we see that because the pores are greater a greater multitude of parts of light may pass together through one pore and because the parts are greater likewise a greater multitude of rays may reflect from the same part and find the same passage quite throughout the Diaphanous body On the contrary side in the second combination where both the pores and the parts of the Diaphanous body are little the light must be but little that finds the same passage Now that refraction is greater or lesser happens two ways for 't is either when one Diaphanous body reflects light at more angles than another and by consequence in a greater extent of the superficies or else when one body reflects light from the
proportion over air and water And this I conceive produces those substāces which we may term co-agulated juyces and which the Latines call succi concreti whos 's first origine seems to have been liquours that have been afterwards dried by the force either of heat or cold Of this nature are all kind of Salts Niters Sulfurs and divers sorts of Bitumens All which easily bewray the relicks and effects of fire left in them some more some less according to their degrees And thus we have in general deduced from their causes the complexions of those bodies whereof the bulk of the world subjected to our use consists and which serve for the production and nourishment of living creatures both animal and vegetable Not so exactly I confess nor so particularly as the matter in it self or as a Treatise confined to that subject would require yet sufficiently for our intent In the performance whereof if more accurate searchers of nature shall find that we have peradventure been mistaken in the minute delivering of some particular bodies complexion their very correction I dare boldly say will justifie our principal scope which is to shew that all the great variety we see among bodies arises out of the commixion of the First Qualities and of the Elements for they will not be able to correct us upon any other grounds then those we have laid As may easily be perceiv'd if we cast a summary view upon the qualities of compounded bodies All which we shall find to spring out of rarity and density and to savour of their origine for the most manifest qualities of bodies may be reduced to certain pairs opposite to one another As namely some are liquid and flowing others are consistent some are soft others hard some are fatty viscuous and smooth others lean gritty and rough some gross others subtile some tough others brittle and the like Of which the liquid the soft the fat and the viscuous are so manifestly derived from rarity that we need not take any further pains to trace out their origine and the like is of their contraries from the contrary cause to wit of those bodies that are consistent hard lean and gritty all which evidently spring from density As for smoothness we have already shew'd how that proceeds from an airy or oily nature and by consequence from a certain degree of rarity And therefore roughness the contrary of it must proceed from a proportionable degree of density Toughness is also a kind of ductility which we have reduced to watriness that is to another degree of rarity and consequently brittleness must arise from the contrary degree of density Lastly grossness and subtilness consist in a difficulty or facility to be divided into small parts which appears to be nothing else but a certain determination of rarity and density And thus we see how the several complexions of bodies are reduced to the four Elements that compound them and the qualities of those bodies to the two primary differences of quantitative things by which the elements are diversified And out of this discourse it will be evident that these complexions and qualities though in diverse degrees must of necessity be found wherever there is any variation in bodies For seeing there can be no variation in bodies but by rarity and density and that the pure degrees of rarity and density make heat cold moisture and driness and in a word the four Elements 't is evident that wherever there is variety of bodies there must be the four Elements though peradventure far unlike these miked bodies which we call Elements And again because these Elements cannot consist without motion and by motion they of necessity produce Mixed bodies and forge out those Qualities which we come from explicating it must by like necessity follow that wherever there is any variety of active and passive bodies there mixed bodies likewise must reside of the same kinds and be indued with qualities of the like natures as those we have treated of though peradventure such as are in other places of the world remote from us may be in a degree far different from ours Since then it cannot be denied but that there must be notable variety of active and passive bodies wherever there is light neither can it be denied but that in all those Great Bodies from which light is reflected to us there must be a like variety of complexions and qualities and of bodies temper'd by them as we find here in the Orb we live in Which Systeme how different it is from that which Aristotle and the most of the School have deliver'd us as well in the evidencies of the proofs for its being so as in the position and model of it I leave to the prudent Readers to consider and judge Out of what has been already said 't is not hard to discover in what manner the composition of bodies is made In effecting which the main hinge wheron that motion depends is fire or heat as it likewise is in all other motions whatever Now because the composition of a mixed body proceeds from the action of one simple body or element upon the others it will not be amiss to declare by some example how this work passes for that purpose let us examine how fire or heat works upon his fellows By what we have formerly deliver'd 't is clear that fire streaming out from its centre and diffusing it self abroad so as to fill the circumference of a larger circle it must needs follow that the beams of it are most condens'd and compacted together near the centre and the further they stream from the centre the more thin and rarified they must grow yet this is with such moderation as we cannot any where discern that one beam doth not touch another and therfore the distances must be very smal Now let us suppose that fire happens to be in a viscuous and tenacious body and then consider what will happen in this case of one side the fire spreads it self abroad on the other side the parts of the tenacious body being moist as I have formerly determin'd their edges on all hands will stick fast to the dry beams of the fire that pass between them Then they stretching wider and wider from one another must needs draw with them the parts of that tenacious body which stick to them and stretch them into a greater widness or largness then they enjoy'd before from whence it follows that seeing there is no other body near therabouts but they two either there must be a vacuity left or else the tenacious body must hold and fill a greater space then it did before and consequently be more rare Contrariwise of any of the other elements be stronger then fire the denser Elements break off from their continu'd stream the little parts of fire which were gotten into their greater parts and sticking on all sides about them so enclose them that they have no more semblance of fire and
shake notably in a fierce wind The reason of all which may be deduced out of what we have said above For since the bending of a body makes the spirits or humours within it to sally forth 't is clear if the violence which forces it be not so sudden nor the motion it receives so quick but that the moisture may oose gently out the body will bend stil more and more as their absence gives it leave But if the motion wrought in it be too quick then the spirits not having time allow'd them to go leisurely and gently out force their prison and break out with a violence and so the body is snap'd in two Here peradventure some remembring what we have said in another place namly that it is the shortness and littleness of the humid parts in a body which makes it stick together and that this shortness may be in so high a degree as nothing can come between the parts they glew together to divide them may ask how a very dense body of such a strain can be broken or divided But the difficulty is not great for since the humid parts in whatever degree of shortness they be must necessarily have stil some latitude it cannot be doubted but there may be some force assign'd greater then their resistance can be All the question is how to apply it to work its effect upon so close a compacted body in which peradventure the continuity of the humid parts that bind the others together may be so small as no other body whatever no not fire can go between them so as to separate part from part At the worst it cannot be doubted but that the force may be so apply'd at the outside of that body as to make the parts of it press and fight one against another and at length by multiplication of the force constrain it to yield and suffer division And this I conceive to be the condition of gold and some precious stones in which the elements are united by such little parts as nothing but a civil war within themselvs stir'd up by some subtile outward enemy wherby they are made to tear their own bowels could bring to passe their destruction But this way of dissolving such bodies more properly belongs to the next way of working upon them by fire yet the same is done when some exteriour violence pressing upon those parts it touches makes them cut a way betwixt their next neighbours and so continuing the force divide the whole body As when the chisel or even the hammer with beating breaks gold asunder for it is neither the chisel nor the hammer that doth that effect immediately but they make those parts they touch cut the others that they are forced upon As I remember hap'ned to a Gentleman that stood by me in a Sea-fight I was in with a coat of mail upon his body when a bullet coming against a bony part in him made a great wound and shatter'd all the bones near where it struck and yet the coat of mail was whole it seems the little links of the mail yielding to the bullets force made their way into the flesh and to the bone But now 't is time to come to the other two instuments of separation of bodies Fire and water and to examine how they dissolve compounds Of these two the way of working of fire is the easiest and most apparant to be discerned We may readily observe how it proceeds if we but set a piece of wood on fire in which it makes little holes as if with bodkins it pierced it So that the manner of its operation in common being plain we need but reflect a little upon the several particular degrees of it Some bodies it seems not to touch as clothes made of Asbestus which are only purifyed by it Others it melts but consumes not as gold Others it turns into powder suddenly dissolving their body as lead and such metalls as are calcined by pure fire Others again it separates into a greater number of differing parts as into Spirits Waters Oyls Salt Earth and Glass of which rank are all vegetables And lastly others it converts into pure fire as strong Waters or Aquavites called Aquae ardentes and some pure Oyls for the smoak that is made by their setting on fire and peradventure their salt is so little as is scarce discernable These are in sum the divisions which fire makes upon bodies according to their nature and its due application to them for by the help and mediation of other things it may peradventure work other effects Now to examine a little in particular how the same fire in differing subjects produces such different effects Limus ut hic durescit haec ut câ—ra liquescit Uno eodemque igni We will consider the nature of every one of the subjects apart by it self First for the Asbestus 't is clear it is of a very dry substance so that to look upon it when it is broken into very little pieces they seem to be little bundles of short hairs the liquidity within being so little as it affords the parts neither length nor breadth and therefore fire meets with little there that it can dilate But what it cannot dilate it cannot separate nor carry away any thing of it but what is accidentally adherent to the outsides of it And so it seems only to pass through the pores and cleanse the little thrids but brings no detriment at all to the substance of it In this I speak only of an ordinary fire for I doubt not but such a one it might be as would perfectly calcine it The next body we spake of is Gold This abounds so much in liquidity that it stickes to the fire if duly apply'd but its humidity is so well united to its earthy parts and so perfectly incorporated with them as it cannot carry away one without both but both are too heavy a weight for the little agile parts of fire to remove Thus it is able to make Gold swell as we see in melting it in which the Gold receives the fire into its bowels and retains it a long time with it but at its departure it permits the fire to carry nothing away upon its wings as is apparant by the Golds no whit decay of weight after never so long fusion And therefore to have fire make any separation in Gold requires the assistance of some other moist body that on the one side may stick closely to the Gold when the fire drives it into it and on the othe rside may be capable of dilatation by the action of the fire upon it As in some sort we see in Strong Waters made of Salts being a proper subject for the fire to dilate which by the assistance of fire mingling themselves closely with little parts of the Gold pull them away from their whole substance and force them to bear them company in their journey upwards in which multitudes of little parts of fire
concur to press on and hasten them and so the weight of gold being at length overcome by these two powerful Agents whereof one supplies what the other wants the whole substance of the metal is in little atomes diffused through the whole body of the water But this is not truly a dissolution or separation of the substantial parts of Gold one from another 't is only a corrosion which brings it into a subtile powder when the water salts are separated from it much like what filing though far smaller or grinding of leaf gold upon a porphyre stone may reduce it into for neither the parts of the water nor of the fire that make themselvs a way into the body of the gold are small and subtile enough to get between the parts that compose the essence of it and therefore all they can attain to is to divide it only in its quantity or bulk not in the composition of its nature Yet I intend not to deny but this is possible to be arrived to either by pure fire duly apply'd or by some other assistance as peradventure by some kind of Mercury which being of a nearer cognation to Metals then any other Liquor is may happily have a more powerful ingression into gold then any other body whatever and being withal very subject to rarefaction may after it is inter'd so perfectly penetrate the gold as it may separate every least part of it and so reduce it into an absolute calx But in this place I explicate no more then what ordinarily passes leaving the mysteries of this Art to those who profess it To go on then with what we have in hand Lead hath abundance of water overmingled with its earth as appears by its easie yielding to be bent any way and by its quiet standing bent in the same position that the force which bowed it leaves it in And therefore the liquid parts of Lead are easily separated from its dry and earthy ones and when it is melted the very shaking of it causes the gross parts to descend and many liquid ones to flie away with the fire so that suddenly it is thus converted into powder But this powder is gross in respect of other metals unless this operation be often reiterated or the fire more powerfully apply'd then what is just enough to bring the body of the Lead into powder The next consideration of bodies that fire works upon is of such as it divides into Spirits Salts Oyls Waters or Phlegms and Earth Now these are not pure and simple parts of the dissolv'd body but new compounded bodies made of the first by the operation of heat As Smoak is not pure water but water and fire together and therefore becomes not water but by cooling that is by the fire flying away from it So likewise those Spirits Salts Oyls and the rest are but degrees of things which fire makes of diverse parts of the dissolved body by separating them one from another and incorporating it self with them And so they are all of them compounded of the four Element and are further resolvable into them Yet I intend not to say that there are not originally in the body before its dissolution some loose parts which have the properties of these bodies that are made by the fire in the dissolving of it For seeing that nature works by the like instruments as art uses she must need in her excesses and defects produce like bodies to what art doth in dissolution which operation of art is but a kind of excess in the progress of nature But my meaning is that in such dissolution there are more of these parts made by the working of fire then were in the body before Now because this is the natural and most ordinary dissolution of things let us see in particular how it is done Suppose then that fire were in a convenient manner apply'd to a body that hath all sorts of parts in it and our own discourse will tell us the first effect it works will be that as the subtile parts of fire divide and pass through that body they will adhere to the most subtile parts in it which being most agile and least bound and incorporated to the bowels of the body and lying as 't were loosly scatter'd in it the fire will carry them away with it These will be the first that are separated from the main body which being retain'd in a fit receiver will by the coldness of the circumdant air grow outwardly cool themselves and become first a dew upon the sides of the glass and then still as they grow cooler condense more and more till at length they fall down congeal'd into a palpable liquor which is composed as you see of the hotest parts of the body mingled with the fire that carried them out and therfore this liquor is very inflamable and easily turn'd into actual fire as you see all Spirits and aquae ardentes of vegetables are The hot and loose parts being extracted and the fire continuing and encreasing those that will follow next are such as though they be not of themselvs loose yet are easiest to be made so and are therfore most separable These must be humide and those little dry parts which are incorporated with the overflowing humide ones in them for no parts that we can arrive to are of one pure simple nature but all mixed and composed of the four Elements in some proportion must be held together with such gross glew as the fire may easily penetrate and separate them And then the humide parts divided into little atoms stick to the lesser ones of the fire which by their multitude of number and velocity of motion supplying what they want of them in bulk carry them away with them And thus these Phlegmatick parts flie up with the fire and are afterwards congeal'd into an insipide water which if it have any savour 't is because the first ardent spirits are not totally separated from it but some few of them remain in it and give some little life to the whole body of that otherwise flat liquor Now those parts which the fire separates next from the remaining body after the fiery and watry ones are carryed away must be such as it can work upon and therfore must abound in humidity But since they stir not till the watry ones are gone 't is evident they are composed of many dry parts strongly incorporated and very subtilly mixed with the moist ones and that both of them are exceeding small and so closely and finely knit together that the fire hath much ado to get between and cut the thrids that tie them together and therfore they require a very great force of fire to carry them up Now the composition of these shewes them to be Aerial and together with the fire that is mingled with them they congeal into that consistence which we call Oyl Lastly it cannot be otherwise but that the fire in all this while of
continual application to the body it thus anatomises hath harden'd as it were rosted some parts into such greatness and driness as they will not flie nor can be carried up with any moderate heat But great quantity of fire being mingled with the subtiler parts of his baked earth makes them very pungent and acrimonious in tast so that they are of the nature of ordinary Salt and so called and by the help of water may easily be separated from the more gross parts which then remain a dead and useless earth By this discourse 't is apparent that fire has been the instrument which hath wrought all these parts of an entire body into the forms they are in for whiles it carried away the fiery parts it swel'd the watry ones and whiles it lifted up them it digested the Aerial parts and whiles it drove up the Oyle it baked the earth and salt Again all these retaining for the most part the proper nature of the substance from whence they are extracted 't is evident that the substance is not dissolv'd for so the nature of the whole would be dissolv'd and quite destroy'd extinguish'd in every part but that onely some parts containing the whole substance or rather the nature of the whole substance in them are separated fromo ther parts that have likewise the same nature in them The third instrument for the separation and dissolution of bodies is Water whose proper matter to work upon is Salt and it serves to supply what the fire could not perform which is the separation of the salt from the earth in calcined bodies All the other parts fire was able to sever but in these he hath so baked the little humidity he hath left in them with their much earth as he cannot divide them any further and so though he incorporates himself with them yet he can carry nothing away with him If then pure water be put upon that chalk the subtilest dry parts of it easily joyn to the supervenient moysture and sticking close to it draw it down to them But because they are the lighter it happens to them as when a man in a boat pulls the land to him that comes not to him but he removes himself and his boat to it so these ascend in the water as they dissolve And the water more and more penetrating them and by addition of its parts making the humidity which glews their earthy parts together greater and greater makes a wider and wider separation between those little earthy parts and so imbues the whole body of the water with them into which they are dispersed in little atomes Those that are of biggest bulk remain lowest in the water and in the same measure as their quantities dissolve into less and less they ascend higher and higher till at length the water is fully replenish'd with them and they are diffused through the whole body of it whiles the more gross and heavy earthy parts having nothing in them to make a present combination between them and the water fall down to the bottome and settle under the water in dust In which because earth alone predominates in a very great excess we can expect no other virtue to be in it but that which is proper to mere earth to wit driness and weight Which ordinary Alchimists look not after and therfore call it Terra damnata but others find a fixing quality in it by which they perform very admirable operations Now if you prove the impregnated water from the Terra damnata and then evaporate it you will find a pure white substance remaining Which by its bulk shews it self to be very earthy and by its pricking and corrasive taste will inform you much fire is in it and by its easie dissolution in a moist place that water had a great share in the production of it And thus the salts of bodies are made and extracted Now as water dissolves salt so by the incorporation and virtue of that corrosive substance it doth more then salt it self can do for having gotten acrimony and more weight by the mixture and dissolution of salt in it it makes it self away into solide bodies even into metalls as we see in brass and iron which are easily rusted by salt dissolving upon them And according as the salts are stronger so this corrasive virtue encreases in them even so much as neither silver nor gold are free from their eating quality But they as well as the rest are divided into most small parts and made to swim in water in such sort as we have explicated above and wherof every ordinary Alchymist teaches the practise But this is not all salts help as well to melt hard bodies and metalls as to corrode them For fome fusible salts flowing upon them by the heat of the fire and others dissolv'd by the steam of the metal that incorporates with them as soon as they are in flux mingle with the natural juice of the metals and penetrate deeper then without them the fire could do and swell them and make them fit to run These are the principal ways of the two last instruments in dissolving of bodies taking each of them by it self But there remains one more of very great importance as well in the works of nature as of art in which both the former are joyned and concur and that is putrefaction Whose way of working is by gentle heat and moisture to wet and pierce the body it works upon wherby 't is made to swel and the hot parts of it being loosen'd they are at length drunk up and drown'd in the moist ones from whence by fire they are easily separated as we have already declared and those moist parts afterwards leaving it the substance remaines dry and falls in pieces for want of the glew that held it together CHAP. XVI An explication of certain Maxims touching the operations and qualities of bodies and whether the Elements be found pure in any part of the World OUt of what we have determin'd concerning the natural actions of bodies in their making and destroying one another 't is easie to understand the right meaning of some terms and the true reason of some maxims much used in the Schools As first when Philosophers attribute to all sorts of corporeal Agents a Sphere of Activity The sense of that manner of expression in fire appears plainly by what we have already declared of the nature and manner of operation of that Element And in like manner if we consider how the force of cold consists in a compression of the body that is made cold we may perceive that if in the cooled body there be any subtile parts which can break forth from the rest such compression wil make them do so Especially if the compression be of little parts of the compressed body within themselvs as well as of the outward bulk of the whole body round about For at first the compression of such causes in the body
either losing his course by steering after a wrong compass or being forced back again with short and obscure relations of discoveries since others that went out before him are return'd with a large account to such as are able to understand and sum it up Which surely our learned Countryman and my best and most honoured Friend and to whom of all men living I am most obliged for to him I ow that little which I know and what I have and shall set down in all this discourse is but a few sparks kindled by me at his great fire has both profoundly and accutely and in every regard judiciously performed in his Dialogues of the World Our task then in a lower strain and more proportionate to so weak shoulders is to look no further then among those bodies we converse with Of which having declared by what course and Engines Nature governs their common motions that are found even in the Elements and from thence are derived to all bodies composed of them we intend now to consider such motions as accompany divers particular bodies and are much admired by whoever understands not the the causes of them To begin from the easiest and most connexed with the actions of the Elements the handsel of our labour will light upon the motions of Rarefaction and Condensation as they are the passions of mixed bodies And first for Rarefaction we may remember how it proceeds originally from fire and depends of heat as is declared in the former Chapter and wherever we find Rarefaction we may be confident the body which suffers it is not without fire working upon it From hence we may gather that when the Air imprison'd in a baloon or bladder swells against what contains it and stretches its case and seeks to break out this effect must proceed from fire or heat though we see not the fire working either within the very bowels of the air or without by pressing upon what contains it and so making it self a way to it And that this latter way is able to work this effect may be convinced by the contrary effect from a contrary cause for ' take a bladder stretch'd out to its greatest extent by air shut up within it and hang it in a cold place you will see it presently contract it self into a less room and the bladder will grow wrinckled and become too big for the air within it But for immediate proof of this position we see that the addition of a very smal degree of heat rarifies the air in a Weather-glass the air receiving the impression of heat sooner then water and so makes it extend it self into a greater place and consequently it presses upon the water and forces it down into a less room then formerly it possessed And likewise we see Quicksilver and other liquors if they be shut up in glasses close stop'd and set in sufficient heat and a little is sufficient for this effect will swell and fill their glasses and at the last break them rather then not find a way to give themselvs more room which is then grown too straight in the glass by reason of the rarefaction of the liquors by the fire working upon them Now again that this effect may be wrought by the inward heat that is inclosed in the bowels of the substance thus shut up both reason and experience assure us For they teach us that if a body which is not extremely compacted but that by its loosness is easily divisible into little parts such a one as Wine or other spiritual liquors be inclosed in a vessel the little atoms that perpetually move up and down in every space of the whole World making their way through every body will set on work the little parts in the Wine for example to play their game so that the hot and light parts if they be many not enduring to be compressed and kept in by the heavie and cold ones seek to break out with force and till they can free themselvs from the dense ones that would imprison them they carry them along with them and make them swell out as well as themselvs Now if they be kept in by the vessel so that they have not play enough they drive the dense ones like so many little hammers or wedges against the sides of it and at length break it and so make themselvs way to a larger room But if they have vent the more fiery hot spirits fly away and leave the other grosser parts quiet and at rest On the other side if the hot and light parts in a liquor be not many nor very active and the vessel be so ful that the parts have not free scope to remove and make way for one another there will not follow any great effect in this kind as we see in Bottle Beer or Ale that works little unless there be some space left empty in the bottle And again if the vessel be very much too big for the liquor in it the fiery parts find room first to swel up the heavie ones and at length to get out from them though the vessel be close stopped for they have scope enough to float up and down between the surface of the liquor and the roof of the vessel And this is the reason that if a little beer or small wine be left long in a great cask be it never so close stop'd it will in time grow dead And then if at the opening of the bung after the cask hath been long unstir'd you hold a candle close to it you shall at the instant see a flash of flame environing the vent Which is no other thing but the subtile spirits that parting from the beer or wine have left it dead and flying abroad as soon as they are permited are set on fire by the flame they meet with in their journey as being more combustible because more subtile then that spirit of wine which is kept in form of liquor and yet that likewise though much grosser is set on fire by the touch of flame And this happens not only to Wine and Beer or Ale but even to water As dayly experience shews in the East Indian Ships that having been five or six yeers at Sea when they open some of their casks of Thames Water in their return homewards for they keep that water till the last as being their best and most durable and that grows lighter and purer by the often purifyings through violent motions in storms every one of which makes new gross and earthy parts fall down to the bottom and other volatile ones ascend to the top a flame is seen about their bungs if a candle be near as we said before of wine And to proceed with confirming this doctrine by further experience we dayly see that the little parts of heat being agitated and brought into motion in any body enter and pierce into other parts and incorporate themselvs with them and set them on fire if they be capable
therof as we see in wet Hay or Flax laid together in great quantity And if they be not capable of taking fire then they carry them with them to the outside when they can transport them no further part flies away other part staies with them as we see in new Bear or Ale and in must of wine in which a substance usually call'd the mother is wrought up to the top Which in wine wil at the last be converted into Tartar when the spirits that are very volatile are flown away and leave those parts from whence they have evaporated more gross and earthy then the others where the grosser and subtiler parts continue still mixed but in Beer or rather in ale this mother which in them we call Barm wil continue longer in the same consistence and with the same qualities for the spirits of it are not so fiery that they must presently leave the body they have incorporated themselvs with nor are hot enough to bake it into a hard consistence And therfore Bakers make use of it to raise their bread which neither will it do unless it be kept from cold both which are evident signs that it works in force of heat and consequently that it continues still a hot and light substance And again we see that after wine or beer hath wrought once a violent motion wil make it work a new As is daily seen in great lightnings and in thunder and by much rocking of them For such motion rarifies and consequently heats them partly by separating the little parts of the liquor which were before as glew'd together therfore lay quietly but now by their pulling a sunder and the liquors growing therby more loose then it was they have freedom to play up and down and partly by beating one part against another which breaks and divides them into lesser atomes and so brings some of them into the state of fire which you may remember is nothing else but a body brought into such a degree of littleness and rarity of its parts And this is the reason why such hard and dry bodies as have an unctuous substance in them are by motion either easily set on fire or at least fire is easily goten out of them As happens in flints and divers other stones which yields fire when they are strucken and if presently after you smel to them you shall perceive an odour of brimstone and burning which is a certain signe that the motion converted into fire the natural Brimstone that was mingled withthe Flint whose denser parts were grown cold and so stuck to the stone And in like manner the Ivywood and divers others as also the Indian Canes which from thence are called Firecanes being rub'd with some other stick of the same nature if they be first very dry will of themselvs set on fire and the like will happen to Coach-wheels in in the Summer if they be overheated with motion To conclude our discourse of Rarefaction we may look a little into the power and efficacity of it which is no where to be seen so clearly as in fire And as fire is the general cause of rarefaction so is it of all bodies the most rarified And therfore 't is no marvel if its effects be the greatest that are in nature seeing 't is the proper operation of the most active Element The wonderful force of it we daily see in Thunder in Guns in Granado's in Mines of which continual experience as well as several Histories witnesse little less then miracles Leaving them to the remarks of curious persons we wil only look into the way by which so main effects proceed from causes that appear so slender 'T is evident that fire as we have said before dilates it self spherically as nature shews us manifestly in bubbles of boyling water and Milk and generally of such substances as are of a viscuous composition for those bubbles being round assure us that the cause which made them did equally dilate them from the Centre to all parts Now then remembring the infinite multiplication which is in fire we may conceive that when a grain of Gun-powder is turn'd into it there are so many little bubbles of a viscuous substance one backing another with great celerity as there are parts of fire more then there were of Gun-powder And if we make a computation of the number and celerity of these bubbles we shall find that although every one of them single seem to be of an inconsiderable force yet the whole number of them together will exceed the resistance of the body move or broken by them especially if we note that when hard substances have not time allow'd them to yield they break the sooner And then we shall not so much admire the extremities we see acted by these means Thus having look'd into the nature of Rarefaction and trac'd the progress of it from the motion of the Sun fire in the next place we are to examine the nature of Condensation And we shall oftentimes find it likewise aneffect of the same cause otherwise working For there being two different ways to dry any wet thing one by taking away that juyce which makes a body liquid the other by putting more drought to the wet body that it may imbibe the moisture this latter way doth as well as the former condense a body for by the close sticking of wet to dry the most part of condensation is effected in compounded bodies The first of these wayes properly and immediately proceeds from heat For heat entring into a body incorporates it self with the moist and viscuous parts it findes there as purging medicines do with humour they work on which when the stomack can no longer entertain by reason of their unruly motions in wrestling together they are both ejected grappling with one another and the place of their contention is thus by the supervenience of a guest of a contrary nature that will not stay long there purged from the superabundance of the former ones that annoy'd it Even so the fire that is greedily drunk up by the watry and viscuous parts of a compounded body and whose activity and restless nature will not endure to be long imprisoned there quickly pierces quite through the body it enters into and after a while streams out at an opposite side as fast as it enters on the side next to it and carries away with it those glewy parts it is incorporated with and by their absence leaves the body they paâ—t from dryer then at the first it was Which course we may observe in Syrops that are boyl'd to a consistence and in broths that are consumed to a jelly over which whiles they are making by the fire under them you see a great steam which is the watry parts that being incorporated with fire fly away in smoke Likewise when the sea-sea-water is condens'd into salt you see it is an effect of the Sun or fire that exhales or boyls
salts solution As soon as you put the first salt into the water it falls down presently to the bottome of it and as the water by its humidity pierces by degrees the little joynts of this salt so the small parts of it are by little and little separated from one another and united to parts of water And so infusing more and more salt this progress will continue till every part of water is incorporated with some part of salt and then the water can no longer work of it self but in conjunction to the salt with which it is united After which if more salt of the same kind be put into the water that water so impregnated will not be able to divide it because it has not any so subtile parts left as are able to enter between the joynts of a salt so closely compacted but may be compared to that salt as a thing of equal driness with it and therfore is unapt to moisten and pierce it But if you put into this compound of salt and water another kind of salt that is of a stronger and drier nature then the former and whose parts are more grosly united then the first salt dissolv'd in the water will be able to get in betwixt the joynts of the grosser salt and divide it into little parts and will incorporate his already-composed parts of salt and water into a decompound of two salts and water till all his parts be anew impregnated with second grosser salt as before the pure water was with the first subtiler salt And so it will proceed on if proportionate bodies be joyn'd till the dissolving composition grow into a thick body To which discourse we may add that when the water is so fully impregnated with the first salt as it will receive no more remaining in the temper 't is in yet if it be heated it will then afresh dissolve more of the same kind Which shews that the reason of its giving over to dissolve is for want of having the water divided into parts little enough to stick to more salt which as in this case the fire doth so peradventure in the other the acrimoniousness of the salt doth it And this is sufficient to give curious wits occasion by making further experiments to Search out the truth of this matter Only we may note what happens in most of the experiencies we have mention'd to wit that things of the same nature joyn better and more easily then others that are more estranged from one another Which is very agreeable to reason seeing that if nature intends to have things consist long together she must fit them for such consistence Which seems to proceed out of their agreement in four qualities First in weight for bodies of divers degrees in weight if they be at liberty seek divers places and consequently substances of like weight must of necessity find one another out and croud together as we have shew'd it is the nature of heat to make them do Now it is apparent that things of one nature must in equal parts have the same or a near proportion ofweight seeing that in their composition they must have the same proportion of Elements The second reason of the consistence of bodies together that are of the same nature is the agreement of their liquid parts in the same degree of rarity and density For as it is the nature of quantity in common to make all parts be one quantity so it is the nature of the degrees of quantity when two parts meet that are of the same degree to make them one in that degree of quantity which is to make them stick together in that degree of sticking which the degree of density that is common to them both makes of its own nature Wheras parts of different densities cannot have this reason of sticking though peradventure they may upon some other ground have some more efficatious one And in this manner the like humide parts of two bodies becomming one the holes or receptacles in which those humide parts are contain'd must also needs be united The third reason is the agreeable proportion which their several figures have in respect of one another For if any humidity be extracted out of a mixed body especially by the virtue of fire it must have left pores of such figures as the humidity that is drawn out of them is apt to be cut into for every humide body not being absolutely humide but having certain dry parts mixed with it is more apt for one kind of figure and greatness then for another and by consequence whenever that humidity shall meet again with the body it was severed from it will easily run through and into it all and fill exactly the cavities pores it passed before The last quality in which bodies that are to consist long together agree is the bigness of the humide dry parts of the same body For if the humide parts be too big for the dry ones 't is clear that the dry ones must needs hang loosly together by them because their glew is in too great a quantity But if the humide parts be too little for the dry on s then of necessity some portion of every little dry part must be unfurnish of glew by means wherof to stick to his fellow and so the sticking parts not being conveniently proportion'd to one another their adhesion cannot be so solid as if each of them were exactly fitted to his fellow CHAP. XVIII Of another motion belonging to particular bodies call'd Atraction and of certain operations term'd Magicall HAving thus ended the two motions of rarefaction and condensation the next that offer themselvs are the locall motions which some bodies have to others These are somtimes perform'd by a plain force in the body towards which the motion is and other whiles by a hidden cause which is not so easily discern'd The first is chiefly that which is ordinarily said to be done by the force of nature to hinder vacuum and is much practis'd by nature as in drawing our breath in sucking and many other natural operations which are imitated by art in making of Pumps Syphons and such other instuments and in that admirable experiment of taking up a heavy Marble stone merely by another lying flat and smoothly upon it without any ther connexion of the two stones together as also by that sport of boyes when they spread a thin moistned leather upon a smooth broad stone press it all over close to it and then by pulling of a string fastned at the middle of the leather they draw up likewise the heavy stone In all which the first cause of the motion proceeds from that body towards which the motion is made and therfore is properly called Attraction For the better understanding and delaring of which let us suppose two marble stones very broad and exceeding smoothly polished to be laid one flat upon the other and let there be a ring fastned at the back part of the
it upon a hedge as that dries away so will their sore amend In other parts they observe that if milk newly come from the cow in the boyling run over into the fire and that this happen often and near together to the same cows milk that cow will have her udder sore inflamed and the prevention is to cast salt immediately into the fire upon the milk The herb Persicaria if it be well rub'd upon Warts and then be laid in some fit place to putrifie causes the Warts to wear away as it rots some say the like of fresh Beef Many examples also there are of hurting living creatures by the like means which I set not down for fear of doing more harm by the evil inclination of some persons into whose hands they may fall then profit by their knowing them to whom I intend this work But to make these operations of nature not incredible let us remember how we have determin'd that every body whatever yields some steam or vents a kind of vapour from it self and consider how they must needs do so most of all that are hot and moist as bloud and milk and all wounds and sores generally are We see that the foot of a Hare or Bear leaves such an impression where the beast has passed as a dog can discern it a long time after and a Fox breaths out so strong a vapour that the hunters themselvs can wind it a great way off and a good while after he is parted from the place Now joyning this to the experiences we have already allow'd of concerning the attraction of heat we may conclude that if any of these vapours light upon a solid warm body which has the nature of a source to them they will naturally congregate and incorporate there and if those vapours be joyn'd with any medicative quality or body they will apply that medicament better then any Chirurgeon can Then if the steam of bloud bloud and spirits carry with it from the weapon or cloth the balsamike qualities of the salve or powder and with them settle upon the wound what can follow but a bettering in it Likewise if the steam of the corruption that is upon the clod carry the drying quality of the wind which sweeps over it when it hangs high in the air to the sore part of the cows foot why is it not possible that it should dry the corruption there as well as it dryes it upon the hedge And if the steam of burned milk can hurt by carrying fire to the dug why should not salt cast upon it be a preservative against it Or rather why should not salt hinder the fire from being carried thither Since the nature of salt always hinders and suppresses the activity of fire as we see by experience when we throw salt into the fire below to hinder the flaming of soot in the top of a chimney which presently ceases when new fire from beneath doth not continue it And thus we might proceed in sundry other effects to declare the reason and possibility were we certain of the truth of them therfore we remit this whole question to the authority of the testimonies CHAP. XIX Of three other motions belonging to particular bodies Filtration Restitution and Electrical attraction AFter these let us cast our eye upon another motion very familiar among Alchymists which they call Filtration It is effected by putting one end of a tongue or label of Flannen or Cotten or Flax into a vessel of water and letting the other end hang over the brim of it And it will by little and little draw all the water out of that vessel so that the end which hangs qâ—t be lower then the superficies of the water and make it all come over into any lower vessel you will reserve it in The end of this operation is when any water is mingled with gross and muddy parts not dissolv'd in the water to separate the pure light ones from the impure By which we are taught that the lighter parts of the water are those which most easily catch And if we will examine in particular how 't is likely this business passes we may conceive that the body or linguet by which the water ascends being a dry one some lighter parts of the water whose chance it is to be near the climbing body of Flax begin to stick fast to it and then they require nothing near so great force nor so much pressing to make them climb up along the flax as they would do to make them mount in the pure air As you may see if you hold a stick in running water shelving against the stream the water will run up along the stick much higher then it could be forced up in the open air without any support though the agent were much stronger then the current of the stream And a ball will on a rebound run much higher upon a shelving board then it would if nothing touch'd it And I have been told that if an egsshell fill'd with dew be set at the foot of a hollow stick the Sun will draw it to the top of the shelving stick wheras without a prop it will not stir it With much more reason then we may conceive that water finding as it were little steps in the Cotton to facilitate its journy upwards must ascend more easily then those other things do so as it once receive any impulse to drive it upwards For the gravity both of that water which is upon the Cotton as also of so many of the confining parts of water as can reach the Cotton is exceedingly allay'd either by sticking to the Cotton and so weighing in one bulk with that dry body or else by not tending down straight to the Center but resting as it were upon a steep plain according to what we said of the arm of a Syphon that hangs very sloping out of the water and therfore draws not after it a less proportion of water in the other arm that is more in a direct line to the Center by which means the water as soon as it begins to climb comes to stand in a kind of cone neither breaking from the water below its bulk being big enough to reach to it nor yet falling down to it But our chief labour must be to finde a cause that may make the water begin to ascend To which purpose consider how water of its own nature compresses it self together to exclude any other body lighter then it is Now in respect of the whole mass of the water those parts which stick to the cotton are to be acounted muchlighter then water not because in their own nature they are so but for the circumstances which accompany and give them a greater disposition to receive a motion upwards then much lighter bodies whiles they are destitute of such helps Wherfore as the bulk of water weighing and striving downwards it follows that if there were any air mingled with it it would to
possess a lesser place drive out the aire so here in this case the water at the foot of the ladder of cotton ready to climb with a very small impulse may be after some sort compared in respect of the water to air by reason of the lightness of it and consequently is forced up by the compressing of the rest of water round about it Which no faster gets up but other parts at the foot of the ladder follow the first and drive them still upwards along the tow and new ones drive the second and others the third and so forth so that with ease they climb up to the top of the filter still driving one another forwards as you may do a fine towel through a musket barrel which though it be too limber to be thrust straight through yet craming still new parts into it at length you will drive the first quite through And thus when these parts of water are got up to the top of the vessel on which the filter hangs and over it on the other side by sticking still to the tow and by their natural gravity against which nothing presses on this side the label they fall down again by little and little and by drops break again into water in the vessel set to receive them But now if you ask why it will not drop unless the end of the label that hangs be lower then the water I conceive it is because the water which is all along upon the flannen is one continued body hanging together as it were a thrid of wire and is subject to like accidents as such a continued body is Now suppose you lay wire upon the edge of the basin which the filter rests on and so make that edge the Centre to ballance it upon if the end that is outermost be heaviest it will weigh down the other otherwise not So fares it with this thrid of water if the end of it that hangs out of the pot be longer and consequently heavier then that which rises it must needs raise the other upwards and fall it self downwards Now the raising of the other implies lifting more water from the Cistern and the sliding of it self further downwards is the cause of its converting into drops So that the water in the cistern serves like the flax upon a distaff and is spun into a thrid of water still as it comes to the flannen by the drawing it up occasion'd by the overweight of the thrid on the other side of the center Which to express better by a similitude in a solid body I remember I have oftentimes seen in a Mercers shop a great heap of massy gold lace lie upon their stall and a little way above it a round smooth pin of wood over which they use to have their lace when they wind it into bottoms Now over this pin I have put one end of the lace as long as it hung no lower then the board upon which the rest of the lace did lie it stird'd not for as the weight of the loose end carried it one way so the weight of the otherside where the whole was drew it the otherway in this manner kept it in equalibrity But as soon as I drew on the hanging end to the heavier then the climbing side for no more weights then is in the air that which lies upon the board having another center then it began to roule to the ground and still drew up new parts of that which lay upon the board till all was tumbled down upon the floor In the same manner it hap'nes to the water in which the thrid of it upon the filter is to be compared fitly to that part of the lace which hung upon the pin and the whole quantity in the cistern is like the bulk of lace upon the Shopboard for as fast as the filter draws it up 't is converted into a thrid like that which is already upon the filter in like manner as the wheel converts the flax into yarn as fast as it draws it out from the distaff Our next consideration will very aptly fall upon the motion of those things which being bent leap with violence to their former figure wheras others return but a little and others stand in that ply wherin the bending hath set them For finding the reason of which effects our first reflection may be to note that a Superficies which is more long then broad contains a less floor then that whose sides are equal or nearer being equal and that of those surfaces whose lines and angles are all equal that which hath most sides and angles contains still the greater floor Whence it is that Mathematicians conclude a circle to be the most capacious of all figures and what they say of lines in respect of a superficies the same with proportion they say of surfaces in respect of the body contained And accordingly we see by consequence that in the making a bag of a long napkin if the napkin be sew'd together longwise it holds a great deal less then if it be sewd together broadwise By this we see plainly that if any body in a thick and short figure be forced into a thinner which by becoming thinner must likewise become either longer or broader for what it loses one way it must get another then that superficies must needs be stretched which in our case is a Physical outside or material part of a solid body not a Mathematical consideration of an indivisible Entity We see also that this change of figures happens in the bending of all those bodies wherof we are now enquiring the reason why some of them restore themselves to their original figures and others stand as they are bent Then to begin with the latter sort we find that they are of a moist nature as among metalls lead and tin and among other bodies those â—which we account soft And we may determine that this effect proceeds partly from the humidity of the body that stands bent and partly from a driness peculiar to it that comprehends and fixes the humidity of it For by the first they are render'd capable of being driven into any figure which nature or art desires and by the second they are preserv'd from having their gravity put them out of what figure they have once receiv'd But because these two conditions are common to all solid bodies we may conclude that if no other circumstance concur'd the effect arising out of them would likewise be common to all such and therfore where we find it otherwise we must seek further for a cause of that transgression As for example if you bend the bodies of young trees or the branches of others they will return to their due figure 'T is true they will somtimes lean towards that way they have been bent as may be seen even in great trees after violent tempests and generally the heads of trees the ears of corn and the grown hedg rows will all bend one way
necessity happen that in the air there come Atoms to the Torrid Zone of that grossness that they cannot suddenly be so much rarified as the subtiler parts of air that are there and therfore the more those subtiler parts are rarified and therby happen to be carried up the stronger and the thicker the heavier Atoms must descend And thus this concourse of air from the Polar parts maintains gravity under the Zodiack where otherwise all would be turned into fire and so have no gravity Now who considers the two Hemispheres which by the Equator are divided will find that they are not altogether of equal complexions but that our Hemisphere in which the Northpole is comprised is much dryer then the other by reason of the greater continent of land in this and the vast tract of Sea in the other and therfore the supply which comes from the divers Hemispheres must needs be of different natures that which comes from towards the Southpole being compared to that which comes from towards the North as the more wet to the more dry Yet of how different complexions soever they be you see they are the emanations of one and the same body Not unlike to what nature hath instituted in the rank of Animals among whom the Male and Female are so distinguish'd by heat and cold moisture and drought that nevertheless all belongs but to one nature and that in degrees though manifestly different yet so near together that the body of one is in a manner the same thing as the body of the other Even so the complexions of the two Hemispheres are in such sort different in the same qualities that nevertheless they are of the same nature and are unequal parts of the same body which we call the Earth Now Alchimists assure us that if two extractions of one body meet together they will incorporate one with the other especially if there be some little difference in the complexion of the extractions Whence it follows that these two streams of air making up one continuate floud of various currents â—om one end of the world to the other each stream that come to the Equator from its own Pole by the extraction of the Sun and that is still supply'd with new matter flowing from its own Pole to the Equator before the Sun can sufficiently rarifie and lift up the Atomes that came first Perpendicularly under its beams as it uses to happen in the effects of Physical causes which cannot be rigorously ajusted but must have some latitude in which nature inclines ever rather to abundance then to defect will pass even to the other pole by the conduct of his fellow in case he be by some occasion driven back homewards For as we see in a Bowl or Pail full of water or rather in a Pipe through which the water runs along if there be a little hole at the bottome or side of it the water will wriggle and change its course to creep out at that Pipe especially if there be a little spiggot or quill at the outside of the hole that by the narrow length of it helps in some sort as it were to suck it So if any of the files of the army or floud of Atoms sucked from one of the Poles to the Equator do there find any gaps or chinks or lanes of retiring files in the front of the other poles battalia of atomes they will press in there in such mannner as we have above declared that water doth by the help of a label of cotten and as is exemplyfied in all the attractions of venime by venimous bodies wherof we have given many examples above and they will go along with them the course they go For as when a thick short gilded ingot of silver is drawn out into a long subtile wyre the wyre continuing still perfectly guilded all over manifestly shews that the outside and the inside of the ingot strangely meet together and intermix in the drawing out so this little stream which like an Eddy current runs back from the Equator towards its own Pole will continue to the end still tincted with the mixture of the other Poles atoms it was incorporated with at his coming to the Equator Now that some little rivolets of air and atoms should run back to their own Pole contrary to the course of their main stream will be easy enough to conceive if we but consider that at certain times of the year winds blow more violently and strongly from some determinate part or Rombe of the world then they do at other times and from other parts As for example our East India Marriners tell us of the famous Monsones they find in those parts whch are strong winds that reign constantly six moneths of the year from one polewards and the other six moneths from the other pole beginning precisely about the Suns entring into such a sign or degree of the Zodiac and continue til about its entrance into the opposite degree And in our parts of the world certain smart Easterly or Northeasterly winds reign about the end of March and beginning of April when it seems that some snows are melted by the spring heats of the Sun And other winds have their courses in other seasons upon other causes All which evidently convince that the course of the air and vapours from the poles to the Equator cannot be so regular and uniform but that many impediments and crosses light in the way to make breaches in it and therby to force it in some places to an opposite course In such sort as we see happens in eddy waters and in the course of a tide wherin the stream ruÌ„ning swiftly in the middle beats the edges of the water to the shore and therby makes it run back at the shore And hence we may conclude that although the main course of air atoms for example from North to South in our Hemisphere can never fail of going on towards the Equator constantly at the same rate in gross nevertheless in several particular little parts of it and especially at the edges of those streams that are driven on faster then the rest by an extraordinary and accidental violent cause it is variously interrupted and somtimes intirely stop'd and other times even driven back to the Northwards And if peradventure any man should think that this will not fall out because each stream seems to be always coming from his one Pole to the Equator and therfore will oppose and drive back any bodies that with less force should strive to swim against it or if they stick to them will carry them back to the Equator We answer that we must not conceive the whole air in body doth every where equally incroach from the Polewards upon the Torrid Zone but as it were in certain brooks or rivulets according as the contingency of all causes put together makes it fall out Now then out of what we have said it will follow that since all
of them To come then to the matter Now that we have explicated the natures of those motions by means wherof bodies are made and destroy'd and in which they are to be consider'd chiefly as passive whiles some exterior agent working upon them causes such alterations in them and brings them to such pass as we see in the changes that are daily wrought among substances The next thing we are to imploy our selves about is to take a survey of those motions which some bodies have wherin they seem to be not so much patients as agents and contain within themselvs the principle of their own motion having no relation to any outward object more then to stir up that principle of motion and set it on work which when it is once in act hath as it were within the limits of its own kingdom and sever'd from commerce with all other bodies whatever many other subaltern motions over which it presides To which purpose we may consider that among the compounded bodies whose natures we have explicated there are some in whom the parts of different complexions are so small so wel mingled together that they make a compound which to our sense seems all quite through of one Homogeneous nature and however it be divided each part retains the entire and compleat nature of the whole Others again there are in which 't is easie to discern that the whole is made up of several great parts of very differing natures and tempers And of these there are two kinds one of such as their differing parts seem to have no relation to one another or correspondence together to perform any particular work in which all of them are necessary but rather they seem to be made what they are by chance and accident and if one part be sever'd from another each is an entire thing by it self of the same nature as it was in the whole and no harmony is destroy'd by such division As may be observ'd in some bodies dig'd out of Mines in which one may see lumps of Metal or stone and glass and such different substances in their several distinct situations perfectly compacted into one continuate body which if you divide the glass remains what it was before the Emerald is still an Emerald the silver is good silver and the like of the other substances the causes of which may be easily deduced out of what we have formerly said But there are other bodies in which this manifest and notable difference of parts carries with it such a subordination of one of them to another as we cannot doubt but that nature made such engines if so I may call them by design and intended that this variety should be in One thing whose unity and being what it is should depend of the harmony of the several differing parts and should be destroy'd by their separation As we see in living Creatures whose particular parts and members being once sever'd there is no longer a living creature to be found among them Now of this kind of bodies there are two sorts The first is of those that seem to be one continuate substance wherin we may observe one and the same constant progress throughout from the lowest to the highest part of it so that the operation of one part is not at all different from that of another but the whole body seems to be the course and throughfare of one constant action varying it self in divers occasions and occurrences according to the disposition of the subject The bodies of the second sort have their parts so notably separated one from the other and each have such a peculiar motion proper to them that one might conceive they were every one a complete distinct total thing by it self and that all of them were artificially tied together were it not that the subordination of these parts to one another is so great and the correspondence between them so strict the one not being able to subsist without the other from whom he derives what is needful for him and again being so useful to that other and having its action and motion so fitting and necessary for it as without it that other cannot be as plainly convinces that the compound of all these several parts must needs be one individuol thing I remember that when I travel'd in Spain I saw there two Engines that in some sort express the natures of these two kinds of bodies One at Toledo the other a Segovia both of them set on work by the current of the river in which the foundation of their machine was laid That at Toledo was to force up water at a great height from the river Tagus to the Alcazar the Kings palace that stands upon a high steep hill or rock almost perpendicular over the river In the bottome there was an indented wheel which turning round with the stream gave motion at the same time to the whole engine which consisted of a multitude of little troughs or square ladles set one over another in two parallel rows over against one another from the bottom to the top and upon two several divided frames of timber These troughs were closed at one end with a traverse board to retain the water from running out there which end being bigger then the rest of the trough made it somewhat like a ladle and the rest of it seem'd to be the handle with a channel in it the little end of which channel or trough was open to let the water pass freely away And these troughs were fasten'd by an axletree in the middle of them to the frame of timber that went from the bottome up to the top so that they could upon that center move at liberty either the shut end downwards or the open end like the beam of a ballance Now at a certain position of the root-wheel if so I may call it all one side of the machine sunk down a little lower towards the water and the other was raised a little higher Which motion was changed as soon as the ground-wheel had ended the remnant of his revolution for then the side that was lowest before sprung up and the other sunk down And thus the two sides of the machine were like two legs that by turns trod the water as in the Vintage men press Grapes in a watte Now the troughs that were fast'ned to the timber which descended turn'd that part of them downwards which was like a Box shut to hold the water and consequently the open end was up in the air like the arm of the ballance to which the lightest scale is fasten'd and in the mean time the troughs upon the ascending timber were moved by a contrary motion keeping their boxends aloft and letting the open ends incline downwards so that if any water were in them they would let it run out wher'as the others retain'd any that came into them VVhen you have made an image of this Machine in your phantasie consider what will follow out
cultivating mans voice as Rhetorick Meetering and Singing 'T is admirable how finely Galileo hath deliver'd us the consonances of Musick towards the end of his First Dialogue of Motion from the 95 page forward on and now he hath shew'd that matter clearly to the sight so making the eye as well as the ear Judge of it in motions of the water in Pendants hanging loose in the air and in permanent notes or traces made upon letton To the moderation of the same many other mechanical arts are imply'd as the Trade of Belfounders and of all Makers of musical instruments by wind or by water or by strings Neither can I slip over without mention the two curious Arts of Echoing and Whispering The first of which teaches to iterate voices several times and is frequently put in practice by those that are delighted with rarities in their gardens And the other shews how to gather into a narrow room the motions of the air that are diffused in a great extent wherby one that shall put his ear to that place where all the several motions meet shall hear what is spoken so low as no body between him and the speaker can discern any sound at all Of which kind there are very fine curiosities in some Churches of England and my self have seen in an upper room of a capacious round Tower vaulted overhead the walls so contrived by chance I believe that two men standing at the utmost opposite points of the Diameter of it could talk very currently and clearly with one another and yet none that stood in the middle could hear a sillable And if one turn'd his face to the wall and spoke against that though never so softly the others ear at the opposite point would discern every word Which puts me in mind of a note made by one that was no friend to Auricular Confession upon occasion of his being with me in a Church that had been of a Monastery where in one corner of it one might sit and hear almost all that was whisper'd through the whole extent of the Church who would not be perswaded but that it was on purpose contrived so by the subtilty of the Friars to the end that the Prior or some of them might sit there and hear whatever the several Penitents accused themselvs of to their Ghostly Fathers so to make advantage by this artifice of what the Confessors durst not of themselvs immediately reveal He allow'd better of the use in Rome of making voyces rebound from the top of the Cupula of St. Peters in the Vatican down to the floor of the Church when on great days they make a Quire of Musick go up to the very highest part of the arch which is into the Lanthorn from whence while they sing the people below just under it are surprised with the smart sound of their voices as though they stood close by them and yet can see no body from whom these notes should proceed And in the the same Cupula if two men stand upon the large cornish or border which circles the bottom of it they may observe the like effect as that I spoke of above in the round Tower In like manner they that are called Ventriloqui perswade ignorant people that the Devil speaks from within them deep in their belly by their sucking their breath inwards in a certain manner whiles they speak whence it follows that their voice seems to come not from them but from somwhat else hidden within them if at least you perceive it comes out of them but if you do not then it seems to come from a good way off To this art belongs the making of Sarabatanes or Trunks to help the hearing and of Echo-glasses that multiply sounds as Burning-glasses do light All which arts and the rules of them follow the laws of motion and every effect of them is to be demonstrated by the principles and proportions of motion therfore we cannot with reason imagine them to be any thing else We see likewise that great noises not only offend the hearing but even shake houses and Towers I have been told by inhabitants of Dover that when the Arch-Duke Albertus made his great battery aganst Calais which for the time was a very furious one for he endeavor'd all he could to take the Town before it could be reliev'd the very houses were shaken and the glass-windows shiver'd with the report of his Artillery And I have been told by one that in Sevil when the gunpowder-house of that Town which was some two miles distant from that place where he lived was blown up that it made the wooden shutters of the windows in his house beat and clap against the walls with great violence and split the very walls of a fair Church that standing next it though at a good distance hand no other building between to shelter it from the impetuosity of the airs sudden violent motion And after a fight I once had with some Galleasses and Galliones in the rode of Scanderone which was a very hot one for the time and a scarce credible number of pieces of Ordnance were shot from my Fleet the English Consul of that place coming afterwards aboard my ship told me that the report of our guns had during all the time of the fight shaken the drinking-glasses that stood upon shelvs in his house and split the paper-windows all about and spoil'd and crack'd all the eggs that his Pigeons were then sitting uppon which loss he lamented exceedingly for they were of that kind which commonly it called Carriers and serve them daily in their commerce between that place and Aleppo And I have often observed at Sea in smooth water that the Ordnance shot off in a ship some miles distant would violently shake the glass-windows in another And I have perceiv'd this effect in my own more then once at the report of a single gun from a ship so far off that we could not descry her I remember how one time upon such an occasion we alter'd our course and steer'd with the sound or rather with the motion at first observing upon which point of the Compass the shaking appear'd for we heard nothing though soon after with much attention and silence we could discerna dul clumsie noise And such a motion grows at the end of it so faint that if any strong resisting body check it in its course 't is presently deaded and will afterwards shake nothing beyond that body and therfore 't is perceptible onely at the outside of the ship if some light and very moveable body hang loosly on that side it comes to receive the impression of it as this sound at the gallery windows of my Cabin upon the poop which were of light Moscovia glass And by then we had run somwhat more then a watch with all the sails abroad we could make and in a fair loom gale we found our selvs near enough to part the fray of two ships that in a little
while longer fighting would have sunk one another But besides the motions in the air which receiv'd them easily by reason of the fluidity of it we see that even solid bodies participate of it As if you knock never so lightly at one end of the longest beam you can find it will be distinctly heard at the other end The trampling of men and horses in a quiet night wil be heard some miles off if one lay their ear to the ground and more sensibly if one make a little hole in the earth and put ones ear into the mouth of it but most of all if one set a Drum smooth upon the ground and lay ones ear to the upper edge of it for the lower membrane of the Drum is shaked by the motion of the earth and then multiplies that sound by the hollow figure of the Drum in the conveying it to the upper membrane upon which your ear leans Not much unlike the Tympane or Drum of the ear which being shaked by outward motion causes a second motion on the inside of it correspondent to this first and this having a free passage to the brain strikes it immediately and so informes it how things move without which is all the mystery of hearing If any thing break or stop this motion before it shake our ear it is not heard And accordingly we see that the sound of Bells or Artillery is heard much further if it have the conduct of waters then through the pure air because in such bodies the great continuity of them makes that one part cannot shake alone and upon their superficies there is no notable unevenness nor any dense thing in the way to check the motion as in the air hills buildings trees and such like so that the same shaking goes a great way And to confirm that this is the true reason I have several times observ'd that standing by a river side I heard the sound of a ring of Bells much more distinctly and loud then if I went some distance from the water though nearer to the steeple from whence the sound came And it is not only the motion of the air that makes sound in our ears but any motion that hath access to them in such a manner as to shake the quivering membranous Tympane within them will represent to us those motions which are without and so make such a sound there as if it were convey'd onely by the air Which is plainly seen when a man lying a good way under water shall there hear the same sounds as are made above in the air but in a more clumsie manner according as the water by being thicker and more corpulent is more unwieldy in its motions And this I have tryed often staying under water as long as the necessity of breathing would permit me Which shews that the air being smartly moved moves the water also by means of its continuity with it and that liquid element being fluide and getting into the ear makes vibrations upon the drum of it like to those of air But all this is nothing in respect of what I might in some sort say and yet speak truth Which is that I have seen one who could discern sounds with his eyes 'T is admirable how one sense will oftentimes supply the want of another whereof I have seen an other strange example in a different strain from this of a man that by his grosser senses had his want of sight wonderfully made up He was so throughly blind that his eyes could not inform him when the Sun shined for all the cry stalline humour was out in both his eyes yet his other senses instructed him so efficaciously in what was their office to have done as what he wanted in them seem'd to be overpay'd in other abilities To say that he would play at Cards and Tables as well as most men is rather a commendation of his memory phantasie then of any of his outward senses But that he should play wel at Bowles and Shovelbord and other games of aim which in other men require clear sight and an exact level of the hand according to the qualities of the earth or table and to the situation and distance of the place he was to throw at seems to exceed possibility And yet he did all this He would walk in a chamber or long alley in a garden after he had been a while used to them as straight and turn as just at the ends as any seeing man could do He would go up and down every where so confidently and demean himself at table so regularly as strangers have sitten by him several meals and seen him walk about the house without ever observing any want of seeing in him which he endeavour'd what he could to hide by wearing his hat low upon his brows He would at the first abord of a stranger as soon as he spoke to him frame a right apprehension of his stature bulk and manner of making And which is more when he taught his Schollers to declame for he was School-master to my sons and lived in my house or to represent some of Seneca's Tragedies or the like he would by their voice know their gesture and the situation they put their bodies in so that he would be able as soon as they spoke to judge whether they stood or sate or in what posture they were which made them demean themselvs as decently before him whiles they spoke as if he had seen them perfectly Though all this be very stange yet me thinks his discerning of lights is beyond it all He would feel in his body and chiefly in his brain as he hath often told me a certain effect by which he knew when the Sun was up and would discern exactly a clear from a cloudy day This I have known him frequently do without missing when for trial sake he has been lodged in a close chamber whereto the clear light or Sun could not arrive to give him any notice by its actual warmth nor any body could come to him to give him private warnings of the Changes of the weather But this is not the relation I intended when I mention'd one that could hear by his eyes if that expression may be permited me I then reflected upon a Noble man of great quality that I knew in Spain the younger brother of the Constable of Castile But the reflection of his seeing of words call'd into my remembrance the other that felt light in whom I have often remark'd so many strange passages with amazement and delight that I have adventured upon the Readers patience to record some of them conceiving they may be of some use in our course of doctrine But the Spanish Lord was born deaf so deaf that if a Gun were shot off close by his ear he could not hear it and consequently he was dumb for not being able to hear the sound of words he could never imitate nor understand them The loveliness of
of extancies as our modern Astronomers shew when they give an account of theface as some call it in the Orbe of the Moon Likewise in regard of soft or of resistent parts light will be reflected by them more or less strongly that is more or less mingled with darkness For whereas it rebounds smartly back if it strikes not upon a hard and a resistent body and accordingly will shew it self in a bright colour it must of necessity not reflect at all or but very feebly if it penetrates into a body of much humidity or loses it self in the pores of it and that little which comes so weakly from it must consequently appear of a duskie die And these two being all the causes of the great variety of colours we see in bodies according to the quality of the body in which the real colour appears it may easily be determined from which of these it proceeds and then by the colour you may judge of the composition and mixture of the rare and dense parts which by reflecting light begets it In fine out of all we have hitherto said in this Chapter we may conclude the Primary intent of our so long discourse which is That the Senses of Living Creatures and the Sensible Qualities in Bodies are made by the Mixtion of Rarity and Density as well as the Natural Qualities we spoke of in their place For it cannot be denied but that heat and cold and the other couples or pairs which beat upon our Touch are the very same as we see in other bodies the qualities which move our Taste and Smel are manifestly a kin and joyn'd with them Light we have concluded to be Fire and of Motion which affects our ear ther 's no dispute so that it is evident how all sensible quaqualities are as truly bodies as those other Qualities which we call natural To this we may add that the Properties of these sensible qualities are such as proceed evidently from Rarity and Density For to omit those which our Touch takes notice of as too plain to be question'd Physitians judg and determine the natural qualities of meat and medicines and simples by their Tastes and Smels By those qualities they find out powers in them to do material operations and such as our instruments of cutting filling brushing and the like do to ruder and grosser bodies all which vertues being in these instruments by the different tempers of Rarity and Density is a convincing argument that it must be the same causes which produce effects of the same kind in their smel and tastes And and as for light 't is known how corporeally it works upon our eyes Again if we look particularly into the composition of the organs of our Senses we shall meet with nothing but such qualities as we find in the composition of all other natural bodies If we search into our Eye we shall discover in it nothing but diaphanety softness divers colours and consistencies which all Anatomists to explicate parallel in other bodies the like is of our Tongue our Nostrils and our Ears As for our Touch that is so material a sense and so diffused over the whole body as we can have no difficulty about it Seeing then that all the qualities we can discover in the organs of our Senses are made by the various minglings of Rarity with Density how can we doubt but that the active powers over these patients must be of the same nature and kind Again seeing that examples above brought convince That the objects of one sense may be known by another who can doubt of a community among them if not of degree at least of the whole kind as we see that the Touch is the groundwork of all the rest and consequently that being evidently corporeal and consisting in a temper of Rarity Density why should we make difficulty in allowing the like of the rest Besides let us compose of Rarity and Density such tempers as we find in our Senses and let us again compose of Rarity and Density such actors as we have determined the qualities we call sensible to be and will it not manifesty follow that these two applyed to one another must produce such effects as we affirm our Senses have that is to pass the outward objects by different degrees to an inward receiver Again let us cast our eyes upon the natural resolution of bodies and how they move us and we shall therby discover both what the Senses are and why they are just so many and that they cannot be more For an outward body may move us either in its own bulk or quantity or as it works upon another The first is done by the Touch the second by the Ear when a body moving the air makes us take notice of his motion Now in resolution there are three active parts proceeding from a body which have power to move us the fiery part which you sees works upon your eyes by the virtue of light the airy part which we know moves our nostrils by being suck'd in with the air And lastly the salt which dissolves in water and so moves our watry sense which is our taste And these being all the active parts that shew themselvs in the resolution of a body how can we imagine there should be any more senses to be wrought upon For what the stable body shews of it self will be reduced to the touch what as it moves to hearing what the resolutions of it according to the natures of the resolved atomes that fly abroad will concern the other three senses as we have declared And more ways of working or of active parts we cannot conceive to spring out of the nature of a body Finally if we cast our eyes upon the intention of nature to what purpose are our Senses but to bring us into knowledge of the natures of the substances we converse withall Surely to effect this there cannot be invented a better or more reasonable expedient then to bring to our judgment seat the likenesses or extracts of those substances in so delicate a model that they may not be offensive or cumbersom like so many patterns presented to us to know by them what the whole piece is For all similitude is a communication between two things in that quality wherin their likeness consists And therfore we cannot doubt but that nature hath given us by the means whe have explicated an essay to all things in the world that fall under our commerce wherby we judge whether they be profitable or nocive to us and yet in so delicate and subtile a quantity as may in no way be offensive to us whiles we take our measures to attract what is good and avoid what is noxious CHAP. XXXII Of Sensation or the motion wherby Sense is properly exercised OUt of the considerations which we have delivered in these last Chapters the Reader may gather the unreasonablenesse of vulgar Philosophers who to explicate life and sense are
other side there remains no likeness at all between them in themselvs as they are in the understanding which is a most evident proof when the weight of it is duly consider'd that the nature of our Soul is mainly different from the nature of all corporeal things that come into our sense By this which we now come from declaring the admiration how corporeal things can be in the Soul and how they are spiritualiz'd by being there will in part be taken away For reflecting that all the notions of the Soul are nothing but the general notion of a Substance or thing joyn'd with some particular respect if we consider that the respects may be so order'd that one respect may be included in another we shall see that there may be some one respect which may include all those respects that explicate the nature of some one thing in this case the general notion of a thing coupled with this respect will contain all whatever is in the thing as for example the notion of a Knife that it is a thing to cut with includes as we have formerly declared all that belongs to a Knife And thus you see how the mystical phrase of corporeal things being spiritualiz'd in the Soul signifies no more but that the similitudes which areoftthem in the Soul are Respects Thus having collected out of the nature of Apprehension in common as much as we conceive needful in this place to prove our assertion our next work must be to try if we can do the like by reflecting on particular apprehensions We consider'd them of two sorts calling one kind universal ones and the other collective ones In the universal ones we took notice of two conditions the abstraction and the universality of them Now truly if we had no other evidence but what will rise from the first of these that alone would convince and carry the conclusion For though among corporeal things the same may be now in one place now in another or somtimes have one figure sometimes another and still be the same thing as for example wax or water yet it is impossible to imagin any bodily thing whatever to be at any time without all kind of figure or without any place at all or indifferent to this or to that and nevertheless all things whatever when they are universally apprehended by the Soul have this condition in her by reason of their abstraction there which in themselvs is impossible to them When we say water fire gold silver bread c. do we mean or express any determinate figure If we do none but that precise figure will serve or content us but 't is evident that of a hundred different ones any and every one doth alike intirely satisfy us When we call for Mony if we reflect upon our fansy peradventure we shall find there a purse of Crowns nevertheless if our messenger brings us a purse of Pistols we shall not except against it as not being what we intended in our mind because it is not that which was painted in our fansy 'T is therfore evident that our meaning and our fansy were different for otherwise nothing would have satisfy'd us but that which was in our fansy Likewise in the very word which is the picture of our notion we see an indifferency for no Dictionary will tell us that this word Mony doth not signify as well Pistols as Crowns and accordingly we see that if our meaning had been precisely of Crowns we should have blamed our selvs for not having named Crowns and not him that brought us Pistols when we spoke to him by the name of Mony ' T◠most clear therfore that our understanding or meaning is 〈◊〉 fix'd or determin'd to any one particular but equally 〈◊〉 to all and consequently that it cannot be like any thing which enters by the Senses and therfore not corporeal The second condition of Universal Apprehensions is their universality which adds to their abstraction one admirable parcularity and it is that they abstract in such sort as to express at the same time even the very thing they abstract from How is it possible that the same thing can be and not be in the same notion Yet let a man consider what he means when he saith every man hath two eyes and he shall see that he expresses nothing wherby any one man is distinguish'd from another and yet the force of this word Every expresses that every man is distinguish'd from another so that in truth he expresses particularity it self in common Now let our smartest and ingeniousest adversary shew or imagine if he can how this may be done in a picture or in a statue or in any resemblance of a body or bodily thing but if he cannot let him acknowledg an eminent and singular propriety in the Soul that is able to do it Let us reflect that particularity in a body is a collection of divers qualities circumstances as that it is white of such a figure in such a place in such a time and an infinitude of such like conditions conglobated together then if our Soul be a Body the expression of the particularity of a Body in the Soul must be a participation in her of such a conglobation or of such things conglobated Now let us imagine if we can how such a participation should be in common and should abstract from all colour all place and all those things of which the conglobation consists and yet we see that in the Soul this is done and he who saith Every man doth not express any colour place or time and nevertheless by saying so he expresses that in every man there is a conglobation of colour place and time For it could not be Every one unless there were such conglobations to make Every one one and if any conglobation were expressed in this term Every one it would not be Every one but only one alone Now if any coordination of parts can unfold and lay open this riddle I wil renounce all Philosophy Understanding Collective Apprehensions will afford us no meaner testimony than the other two for the spirituality of our Soul For though it may seem to us before we reflect throughly on the matter that we see or otherwise discern by our sense the Numbers of things as that the men in the next room are Three that the Chairs there are Ten and the like of other things yet after due consideration we shall find that our eye or sense tells us but singly of each one that it is One and so runs over every one of them keeping them still each by themselvs under their own several unities but then the Understanding comes and joyns under one notion what the Sense kept asunder in so many several ones as there are things The notion of three or ten is not in the things but in our mind for why three rather than five or ten rather than twelve if the matter of which we
we should be certain that thy parting from this life waft thee over to assured happiness For thou well know'st that there are noxious actions which deprave infect the Soul while it is forging and moulding here in its Body and tempering for its future Being and if thou should'st sally hence in such a pervers disposition unhappiness would betide theeinstead of thy presumed Bliss I see some men so ravenous after those pleasures which cannot be enjoy'd out of the Body that if those impotent desires accompany their Souls into Eternity I cannot doubt of their enduring an eternity of Misery I cannot doubt of their being tormented with such a dire extremity of unsatisfiable desire and violent grief as were able to tear all this world into pieces were it converted into one heart and to rive in sunder any thing less than the necessity of contradiction How high the Bliss of a well-govern'd Soul is above all power of quantity so extreme must be the ravenous inclemency and Vulture-like cruelty of such an uncompassable desire gnawing eternally upon the Soul for the same reason holds in both and which way soever the gravitation and desires of a Separated Soul carry it it is hurried on with a like impetuosity and unlimited activity Let me then cast a heedful and wary eye on the actions of the generality of mankind from whence I may guess at the weal or wo of their future state and if I find that the greatest number weighs down in the scale of misery have I not reason to fear lest my lot should prove among theirs For the greatest part sweeps along with it every particular that hath not some particular reason to exempt it from the general law Instead then of a few that wisely settle their hearts on legitimate desires what multitudes of wretched men do I see some hungry after Flesh and Blood others gaping after the empty wind of Honour and Vanity others breathing nothing but Ambitious thoughts others grasping all and grov'ling upon heaps of melted Earth So that they put me all in a horror and make me fear lest very few they be that are exempted from the dreadful fate of this incomprehensible misery to which I see and grieve to see the whole face of mankind desperately turned May it not then be my sad chance to be one of their unhappy number Be content then fond man to live Live yet till thou hast first secured the passage which thou art but once to venture on Be sure before thou throwst thy self into it to put thy Soul into the Scales ballance all thy thoughts examine all thy inclinations put thy self to the test try what dross what pure gold is in thy self and what thou findest wanting be sure to supply before nature calls thee to thy dreadful account 'T is soon done if thou beest what thy nature dictates thee to be Follow but evident reason and knowledg and thy wants are supply'd thy accounts made up The same evershining truth which makes thee see that two and two are four will shew thee without any contradiction how all these base allurements are vain and idle and that there is no comparison between the highest of them and the meanest of what thou maist hope for hast thou but strength to settle thy heart by the steerage of this most evident Science In this very moment thou maist be secure But the hazard is great in missing to examine thy self truly and throughly And if thou miscarry there thou art lost for ever Apply therfore all thy care all thy industry to that Let that be thy continual study and thy perpetual entertainment Think nothing else worth the knowing nothing else worth the doing but screwing up thy Soul to this height but directing it by this level by this rule Then fear not nor admit the least doubt of thy being happy when thy time shall come and that time shall have no more power over thee In the mean season spare no pains forbear no diligence employ all exactness burn in Summer freeze in Winter watch by night labour by day joyn months to months entail years upon years Think nothing sufficient to prevent so main a hazard and deem nothing long or tedious in this life to purchase so happy an Eternity The first discoverers of the Indies cast themselvs among swarms of Man eaters they fought and strugled with unknown ways so horrid ones that often times they perswaded themselvs they climb'd up mountains of waters and straight again were precipitated headlong down between the cloven sea upon the foaming sand from whence they could not hope for a resource Hunger was their food Snakes and Serpents were their dainties sword and fire were their daily exercise and all this only to be masters of a little Gold which after a short possession was to quit them for ever Our searchers after the Northern passage have cut their way through mountains of ice more affrightful and horrible than the Simplegades They have imprison'd themselvs in half-year nights they have chain'd themselvs up in perpetual stone-cleaving colds some have been found closely embracing one another to conserve as long as they were able a little sewell in their freezing hearts at length petrefy'd by the hardness of that unmerciful winter Others have been made the prey of inhumane men more savage than the wildest Beasts others have been never found nor heard of so that surely they have proved the food of ugly monsters of that vast icy Sea And these have been able and understanding men What motives what hopes had these daring men What gains could they promise themselvs to countervail their desperate attempts They aim'd not so much as at the purchase of any treasure for themselvs but meerly to second the desires of those that set them on work or to fill the mouths of others from whence some few crumes might fall to them What is required at thy hands my Soul like this And yet the hazard thou art to avoid and the wealth thou art to attain imcomparably over-sets all that they could hope for Live then and be glad of long and numerous years that like ripe fruit thou maiest drop securely into that passage which duely entred into shall deliver thee into an eternity of Bliss and unperishable happinesâ— And yet my Soul be thou not too sore agast with the apprehension of the dreadful hazard thou art in Let not a tormenting fear of the dangers that surround thee make thy whole life here bitter and uncomfortable unto thee Let the serious and due consideration of them arm thee with caution and wisedom to prevent miscarriage by them But to look upon them with horrour and affrightedness would freez thy spirits and benum thy actions and peradventure engulf thee through pusillanimity in as great mischâ—iefs as thou seekest to avoid 'T is true the harm which would accrue from misgoverning thy passage out of this life is unspeakable is unimaginable But why shouldst thou take so deep thoughts of
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
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
away all the palpable moisture And so when wet cloathes are hang'd either in the Sun or at the fire we see a smoake about the cloathes and heat within them which being all drawn out from them they become dry And this deserves a particular note that although they should be not quite dry when you take them from the fire yet by that time they are cool they will be dry for the fire that is in them when removed from the main stock of fire flying away carries with it the moisture that was incorporated with it And therfore whiles they were hot that is whiles the fire was in them they must also be moist because the fire and the moisture were grown to be one body and could not become through dry with that measure of fire for more would have dry'd them even whiles they were hot until they were also grown through cold And in like manner Syrups Hydromels Gellies and the like grow much thicker after they are taken off from the fire than they were upon the fire and much of their humidity flies away with the fire in their cooling wherby they lessen much of their quantity even after the outward fire hath ceased from working upon them Now if the moist parts that remain after the drying be by the heat well incorporated in the dry parts and so occasion the dry parts to stick close together then that body is condensed and will to the proportion of it be heavier in a less bulk as we see that Metals are heavier than Stones Although this effect be in those examples wrought by heat yet generally speaking it is more proper to cold which is the Second Way of drying a moist body As when in Greenland the extreme cold freeses the Whalefishes Beer into Ice so that the stewards divide it with Axes and Wedges and deliver their portions of drinks to their ships company and their Shallops gings in their bare hands but in the innermost part of the Butt they find some quantity of very strong liquor not inferiour to moderate spirit of Wine At first before custome had made it familiar to them they wonder'd that every time they drew at the tap when first it came from their ships to the shore for the heat of the hold would not let it freese no liquor would come unless they new tap'd it with a longer gimlet but they thought that pains well recompen'd by finding it in the tast to grow stronger and stronger till at last their longest gimlets would bring nothing out and yet the vessel not a quarter drawn off which obliged them then to stave the Cask that so they might make use of the substance that remain'd The reason of this is evident That cold seeking to condense the beer by mingling its dry and cold parts with it those that would indure this mixture were imbibed and shrunk up by them But the other rare and hot parts that were squees'd out by the dense ones which enter'd to congeal the beer and were forced into the middle of the vessel which was the furthest part for them to retire to from their invironing enemies conserv'd themselvs in their liquid form in defiance of the assaulting cold whiles their fellows remaining by their departure more gross and earthy then they were before yielded to the conquerour they could not shift away from and so were dry'd and condens'd in ice which when the Marriners thaw'd they found like fair water without any spirits in it or comforting heat to the stomack This manner of condensation which we have described in the freezing of Beer is the way most practis'd by nature I mean for immediate condensation for condensation is secondarily wherever there is rarefaction which we have determin'd to be an effect of heat And the course of it is that a multitude of earthy and dry bodies being driven against any liquor easily divide it by means of their density their driness and their littleness all which in this case accompany one another and are by us determin'd to be powerful dividers and when they are gotten into it they partly suck into their own pores the wet and diffused parts of the liquid body and partly they make them when themselvs are full stick fast to their dry sides and become as a glew to hold themselves strongly together And thus they dry up the liquor and by the natural pressing of gravity contract it into a lesser room No otherwise then when we force much wind or water into a bottle and by pressing it more and more make it lye closser then of its own nature it would do Or rather as when ashes are mingled with water both those substances stick so close to one another that they take up less room theâ— they did each apart This is the method of Frosts and Snow and Ice both natural and artificial For in natural freezing ordinarily the North or Northeast Wind by its force brings and drives into our liquors such earthy bodies as it has gather'd from rocks cover'd with snow which being mix'd with the light vapours whereof the wind is made easily find way into the liquors and then they dry them into that consistence we call Ice Which in token of the wind it has in it swims upon the water and in the vessel where it is made rises higher then the water did wherof it is composed and ordinarily it breaks from the sides of the vessel so giving way to more wind to come in and freeze deeper and thicker But because Galileus In his Discourses Intorno alle cose che stanno in su l' accqua pag. 4. was of opinion that Ice was water rarified and not condens'd we must not pass over this verity without maintaining it against the opposition of so powerful an adversary His arguments are first that Ice takes up more place then the water did of which it was made which is against the nature of condensation Secondly that quantity for quantity Ice is lighter then water wheras things that are more dense are proportionally more heavie And lastly that Ice swims in water wheras we have aften taught that the more dense desends in the more rare Now to reply to these arguments we say first that We would gladly know how he did to measure the quantity of the Ice with the quantity of the Water of which it was made and then when he hath shew'd it and shew'd withall that Ice holds more place then water we must tell him that his experiment concludes nothing against our doctrine because there is an addition of other bodies mingled with the water to make Ice of it as we touch'd above and therefore that compound may well take up a greater place then the water alone did and yet be denser then it and the water also be denser then it was And that other bodies do come into the water and are mingled with it is evident out of the exceeding coldness of the aire or some very old wind one of
judgment can acquire no denomination of perfection or deficiency from length or shortness for they belong originally to the matter of the judgment and the judgment must accordingly fit it self to that and therfore is liable neither to commendations nor reproach for being long or short It remains then that the vertue in judging answerable to the quantity of motion must consist in quickness and celerity and the contrary vice in slowness and heaviness As for order in the several parts of motion we know that if they be well order'd they are distinct and easily discernable which vertue in our subject is called clearness of judgment as the contrary vice is confusion CHAP. III. Of Discoursing IN the last Chapter we have shew'd how two Apprehensions joyn'd together make a Judgment How in this our first employment will be to shew how three of these thoughts or Judgments well chosen and duly order'd compose the first and most simple of perfect discourses which Logicians call a Syllogism whose end and effect is to gain the knowledge of somthing before hidden and unknown The means wherby this is compassed is thus By the two first Judgments we joyn the extremes of the proposition we desire to know to some third thing and then by seeing that they both are one third thing and that one can be but one we come to discern that truly one of them is the other which before we saw not So that the Identity which first made an Identical proposition be known and agreed to and afterwards caused the like assent to be yielded to those maximes whose Identification presently shew'd it self now by a little circuit and bringing in of a third term makes the two first whose Identification was hidden and obscure whiles we look'd upon the terms themselvs appear to be in very truth but one thing The various mingling and disposing of these three terms in the two first propositions begets a variety in the Syllogisms composed of them and it consists in this that the assumed term to which the other two are interchangably joyn'd is either said of them or they of it And from hence spring three different kinds of Syllogisms for either the assumed or middle term is said of both the other two or both they are said of it or it is said of one of them and the other is said of it Nither is there any deeper mystery than this in the three figures our great Clerks talk so much of which being brought into Rules to help our memory in the ready use of this transposition of the terms if we spin our thoughts upon them into over small threds and therof weave too intricate webs mean while not reflecting upon the solid ground within our selvs wheron these rules are built nor considering the true end why we may spend our time in trivial and useless subtilities and at length confound and misapply the right use of our natural discourse with a multitude of precepts drawn from artificial Logick But to return to our matter in hand Under this primary threefold variety is another of greater extent growing out of the divers composition of the three terms as they are qualifyed by affirmation or negation and by universality or particularity for that unity which the two terms whose Identification is enquired after must have by being joyn'd with the third becomes much varied by such divers application and from hence shoots up that multitude of kinds of Syllogisms which our Logicians call Moods All which I have thus particularly expressed to the end we may observe how this great variety hangs upon the sole string of Identity Now these Syllogisms being as it were interlaced and woven one within another so that many of them make a long chain wherof each is a link breed or rather are all the variety of mans life They are the steps by which we walk in all our conversations and businesses Man as Man doth nothing else but weave such chains whatever he doth swerving from this work he doth as deficient from the nature of man and if he do ought beyond this by breaking out into divers sorts of exteriour actions he findes nevertheless in this linked sequel of simple discourses the art the cause the rule the bounds and the model of it Let us take a summary view of the vast extent of it in what an immense Ocean one may securely sail by that never varying Compass when the needle is rightly touch'd and fitted to a well moulded box making still new discoveries of regions far out of the sight and belief of them who stand upon the hither shore Humane Operations are comprised under the two general heads of Knowledge and Action if we look but in gross upon what an infinity of divisions these branch themselvs into we shall become giddy our brains will turn our eyes grow weary and dim with aiming only at a suddain and roving measure of the most conspicuous among them in the way of knowledge We see what mighty works men have intended their labours to not only by wild discourses of which huge volums are composed but even in the rigorous method of Geometry Arithmetick and Algebra in which an Euclide an Apollonius an Archimedes a Diophantus and their followers have reach'd such admirable heights and have wound up such vast bottoms Somtimes shewing by effects that the thing proposed must needs be as they have set down and cannot possibly be any otherwise otherwhiles appaying the understanding which is never truly at rest till it hath found the Causes of the effects it sees by exposing how it comes to be so that the Reader calling to mind how such a thing was taught him before and now finding another unexpectedly convinced upon him easily sees that these two put together make and force that third to be wherof he was before in admiration how it could be effected which two ways of discourse are ordinarily known by the names of Demonstrations the one called a priori the other a posteriori Now if we look into the extent of the deductions outof these we shall find no end In the Heavens we may perceive Astronomy measuring whatever we can imagine and ordering those glorious lights which our Creatour hath hang'd out for us and shewing them their ways and picking out their paths and prescribing them for as many ages as he pleases before hand the various motions they may not swerve from in the least circumstance Nor want their Sublime Souls that tell us what metal they are made of what figures they have upon what pillars they are fixed upon what gimals they move and perform their various perious witness that excellent and admirable work I have so often mention'd in my former Treatise If we look upon the Earth we shal meet with those that will tell us how thick it is and how much room it takes up they will shew us how Men and Beasts are hang'd to it by the heels how the Water
and Air covers it what force and power Fire has upon them all what working is in the depths of it and of what composition the main body of it is framed where neither our eys can reach nor any of our Senses sends its messengers to gather and bring back any relations of it Yet are not our Masters contented with all this the whole world of Bodies is not enough to satisfy them the knowledg of all corporeal things and of this machine of heaven and earth with all that they enclose cannot quench the unlimited thirst of a noble mind once set on fire with the beauty and love of Truth Aestuat infoelix angusto limite mundi Ut Gyâ—rae clausus scopulis parvaque Seripho But such heroick spirits cast their subtile nets into another world after the winged inhabitants of the heavens and find means to bring them also into account and to serve them how imperceptible soever they be to the senses as dainties at the Souls table They enquire after a Maker of the world we see and are our selves a main part of and having found Him they conclude Him out of the force of contradiction to be Eternal Infinite Omnipotent Omniscient Immutable and a thousand other admirable qualities they determine of him They search after his Tools and Instruments wherwith he built this vast and admirable pallace and seek to grow acquainted with the Officers and Stewards that under him govern this orderly and numerous Family They find them to be Invisible Creatures exalted above us more than we can estimate yet infinitely farther short of their and our Maker than we are of them If this occasion them to cast their thoughts upon Man himself they find a nature in him 't is true much inferiour to these admirable Intelligences yet such an one as they hope may one day arrive to the likeness of them and that even at the present is of so noble a mould as nothing is too big for it to fathome nor any thing too small for it to discern Thus we see knowledg hath no limits nothing escapes the toils of Science all that ever was that is or can ever be is by them circled in their extent is so vast that our very thoughts and ambitions are too weak and too poor to hope for or aim at what by them may be compassed And if any man that is not inured to raise his thoughts above the pitch of the outward objects he converses daily with should suspect what I have now said is rather like the longing dreams of passionate Lovers whose desires feed them with impossibilities than that it is any real truth or should imagine it but a Poetick Idea of Science that never was nor will be in act or if any other that hath his discoursing faculty vitiated and perverted by having been imbued in the Schools with unsound and umbratile principles should perswade himself that however the pretenders to learning and Science may talk loud of all things and make a noise with Scholastick terms and perswade their ignorant hearers that they speak and unfold deep mysteries yet in very truth nothing at all can be known I shall beseech them both to suspend their conjectures or beliefs herein and to reserve their censure of me whether or no I have strain'd too far till the learned Author of the Dialogues of the World hath enriched it with the Work he hath composed of Metaphysicks in which going orderly and rigorously by continued propositions as Mathematicians demonstrate their undertakings he hath left no scope for wrangling brains to make the least cavil against his doctrine and casting his sharp-sighted thoughts over the whole extent of nature and driving them up to the Almighty Author of it he hath left nothing out of the verge of those rules and all-comprehending principles he gives of true Science And then I doubt not but they will throughly absolve me from having used any amplification in aiming at the reach of this all grasping power For my part the best expression I am able to make of this admirable piece I must borrow from witty Galileus when he speaks of Archimedes's long miss'd Book of Glasses and profess that having some of the Elements or Books of it entrusted in my hands by the Author I read them over with extreme amazement as well as delight for the wonderful subtilty and solidness of them Thus much for knowledge Now let us cast an eye upon humane actions All that we do if we do it as we should and like men is govern'd and steer'd by two sorts of qualities the one of which we call Arts the other Prudence An Art is a collection of general rules comprehending some one subject upon which we often work The matters we work on out of which the particular subjects of Arts do spring are of three kinds our Selves our Neighbours and such dumb or insensible things as compose the Rest of the World Our actions on our Selves are the highest and noblest of all the rest and those by which we live and work as men or to express my self better they are those by which we perfect that part of us which makes us men and by which we direct and level all we do according to the rule of reason not suffering our actions to swerve from what she dictates to us This is done by multiplying and heightning the thoughts of those things which maintain us in reason whether the motives be moral as the examples of worthy persons and the precepts and perswasions of wise men and the like or natural as the consideration of the sweet and contented life which vertue givs us here by good conversation honour profit quiet pleasure and what else soever grows out of so excellent a root as also of the Beatitude and Happiness it brings us to in the next state and of the contrary effects which spring from vice Again by observing the motives and wayes of our passions and animal desires we learn how to prevent them how to terrifie them and how to wear them away by little and little through sometimes giving them diversions otherwhiles restraining them with moderation and oftentimes cutting off the occasions and abridging them of their natural encreasings All these things are brought into art and rule whose lessons were men but as careful and industrious to study as they are to become masters in vain and trivial things they would enjoy happy lives In the next place we are to consider the actions wherby we work upon our Neighbours They are chiefly government and negotiation both which are of one kind and have but this difference that the one is done in common the other is perform'd in particular The means by which we command are rewards and punishments which who hath in his hands may assuredly by wise using them bring to pass whatever he has a mind to Upon occasion of mentioning these two powerful motives which have so main an influence in mens actions we may note