the thing Perceived and it is more accurately said that we see the Sun then that we see the Light For Light Colour Heat Sound and other qualities which are commonly called Sensible are not Objects but Phantasms in the Sentients For a Phantasm is the act of Sense and differs no otherwise from Sense then fieri that is Being a doing differs from Factum esse that is Being done which difference in things that are done in an Instant is none at all and a Phantasme is made in an Instant For in all Motion which proceeds by perpetual propagation the first part being moved moves the second the second the third and so on to the last and that to any distance how great soever And in what point of time the first or formost part proceeded to the place of the second which is thrust on in the same point of time the last save one proceeded into the place of the last yeilding part which by reaction in the same instant if the reaction be strong enough makes a Phantasme and a Phantasme being made Perception is made together with it 4 The Organs of Sense which are in the Sentient are such parts thereof that if they be hurt the very generation of Phantasmes is thereby destroyed though all the rest of the parts remain intire Now these parts in the most of Living Creatures are found to be certain Spirits and Membranes which proceeding from the Pia Mater involve the Brain and all the Nerves also the Brain it self and the Arteries which are in the Brain and such other parts as being stirred the Hart also which is the fountain of all Sense is stirred together with them For whensoever the action of the Object reacheth the Body of the Sentient that action is by some Nerve propagated to the Brain and if the Nerve leading thither be so hurt or obstructed that the Motion can be propagated no further no Sense follows Also if the motion be intercepted between the Brain and the Heart by the defect of the Organ by which the action is propagated there will be no perception of the Object 5 But though all Sense as I have said be made by Reaction nevertheless it is not necessary that every thing that Reacteth should have Sense I know there have been Philosophers those learned men who have maintained that all Bodies are endued with Sense Nor do I see how they can be refuted if the nature of Sense be placed in Reaction onely And though by the Reaction of Bodies inanimate a Phantasme might be made it would nevertheless cease as soon as ever the Object were removed For unless those Bodies had Organs as living Creatures have fit for the retaining of such Motion as is made in them their Sense would be such as that they should never remeÌ„ber the same And therefore this hath nothing to do with that Sense which is the subject of my discourse For by Sense we commonly understand the judgement we make of Objects by their Phantasmes namely by comparing and distinguishing those Phantasmes which we could never do if that motion in the Organ by which the Phantasme is made did not remain there for some time and make the same Phantasme return Wherefore Sense as I here understand it and which is commonly so called hath necessarily some memory adhering to it by which former and later Phantasmes may be compared together and distinguished from one another Sense therefore properly so called must necessarily have in it a perpetual variety of Phantasmes that they may be discerned one from another For if we should suppose a man to be made with cleer Eyes and all the rest of his Organs of Sight well disposed but endued with no other Sense and that he should look onely upon one thing which is alwayes of the same colour and figure without the least appearance of variety he would seem to me whatsoever others may say to see no more then I seem to my self to feel the Bones of my own Limbs by my Organs of Feeling and yet those Bones are alwayes and on all sides touched by a most sensible Membrane I might perhaps say he were astonished and looked upon it but I should not say he saw it it being almost all one for a man to be alwayes sensible of one and the same thing and not to be sensible at all of any thing 6 And yet such is the nature of Sense that it does not permit a man to discern many things at once For seeing the nature of Sense consists in Motion as long as the Organs are employed about one Object they cannot be so Moved by another at the same time as to make by both their Motions one sincere Phantasme of each of them at once And therefore two several Phantasmes will not be made by two Objects working together but onely one Phantasme compounded from the action of both Besides as when we divide a Body we divide its place and when we reckon many Bodies we must necessarily reckon as many places and contrarily as I have shewn in the first Article of the 7th Chapter so what number soever we say there be of Times we must understand the same number of Motions also and as oft as we count many Motions so oft we reckon many times For though the object we looke upon be of diverse colours yet with those diverse colours it is but one varied Object and not variety of Objects Moreover whilest those Organs which are common to all the Senses such as are those parts of every Organ which proceed in Men from the root of the Nerves to the Hart are vehemently stirred by a strong action from some one Object they are by reaof the contumacy which the motion they have already gives them against the reception of all other motion made the lesse fit to receive any other impression from whatsoever other Objects to what sense soever those Objects belong And hence it is that an earnest studying of one Object takes away the Sense of all other Objects for the present For Study is nothing else but a possession of the mind that is to say a vehement motion made by some one Object in the Organs of Sense which are stupid to all other motions as long as this lasteth according to what was said by Terence Populus studio stupidus in funambulo animum occuparat For what is Stupor but that which the Greekes call 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 that is a cessation from the Sense of other things Wherefore at one and the same time we cannot by Sense perceive more then one single Object as in reading we see the letters successively one by one and not all together though the whole Page be presented to our eye and though every severall letter be distinctly written there yet when we looke upon the whole page at once we read nothing From hence it is manifest that every endeavour of the Organ â—utwards is not to be called Sense but that onely which
nothing but perturbed Light is comprehended Wherefore the Phantasme of a Lucid Body is Light and of a coloured Body Colour But the Object of Sight properly so called is neither Light nor Colour but the Body itself which is lucid or enlightned or coloured For Light and Colour being Phantasmes of the Sentient cannot be Accidents of the Object Which is manifest enough from this that Visible things appear oftentimes in places in which we know assuredly they are not and that in different places they are of different colours and may at one and the same time appear in divers places Motion Rest Magnitude and Figure are common both to the Sight and Touch and the whole appearance together of Figure and Light or Colour is by the Greeks commonly called 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 and by the Latines Species and Imago all which names signifie no more but Appearance The phantasme which is made by Hearing is Sound by Smell Odour by Tast Savour and by Touch Hardness and Softness Heat and Cold Wetness Oiliness and many more which are easier to be distinguished by sense then words Smoothness Roughness Rarity and Density refer to Figure and are therefore common both to Touch and Sight And as for the Objects of Hearing Smel Tast and Touch they are not Sound Odour Savour Hardness c. but the Bodies themselves from which Sound Odour Savour Hardness c. proceed Of the causes of which and of the manner how they are produced I shall speak hereafter But these Phantasmes though they be effects in the Sentient as Subject produced by Objects working upon the Organs yet there are also other effects besides these produced by the same Objects in the same Organs namely certain Motions proceeding from Sense which are called Animal Motions For seeing in all Sense of external things there is mutual Action and Reaction that is two Endeavours opposing one another it is manifest that the motion of both of them together will be continued every way especially to the confines of both the Bodies And when this happens in the internal Organ the Endeavour outwards will proceed in a solid Angle which will be greater and consequently the Idea greater then it would have been if the impression had been weaker 11 From hence the Natural cause is manifest First why those things seem to be greater which caeteris paribus are seen in a greater Angle Secondly why in a serene cold night when the Moon doth not shine more of the fixed Stars appear then at another time For their action is less hindred by the serenity of the Aire and not obscured by the greater Light of the Moon which is then absent and the Cold making the Air more pressing helpeth or strengtheneth the action of the Stars upon our Eies in so much as Stars may then be seen which are seen at no other time And this may suffice to be said in general concerning Sense made by the Reaction of the Organ For as for the place of the Image the deceptions of Sight and other things of which we have experience in our selves by Sense being they depend for the most part upon the Fabrick it self of the Eie of Man I shall speak of them then when I come to speak of Man 12 But there is another kind of Sense of which I will say somthing in this place namely the Sense of Pleasure and Pain proceeding not from the Reaction of the Heart outwards but from continual action from the outermost part of the Organ towards the Heart For the original of Life being in the Heart that motion in the Sentient which is propagated to the Heart must necessarily make some alteration or diversion of Vital Motion namely by quickning or slackening helping or hindering the same Now when it helpeth it is Pleasure and when it hindereth it is Pain Trouble Grief c. And as Phantasmes seem to be without by reason of the Endeavour outwards so Pleasure and Pain by reason of the Endeavour of the Organ inwards seem to be within namely there where the first Cause of the Pleasure or Pain is as when the Pain proceeds from a Wound we think the Pain and the Wound are both in the same place Now Vital Motion is the Motion of the Bloud perpetually circulating as hath been shewn from many infallible signes and marks by Doctor Harvey the first Observer of it in the Veins and Arteries Which Motion when it is hindered by some other Motion made by the action of sensible Objects may be restored again either by bending or setting straight the parts of the Body which is done when the Spirits are carried now into these now into other Nerves till the Pain as farre as is possible be quite taken away But if Vital Motion be helped by Motion made by Sense then the parts of the Organ will be disposed to guide the Spirits in such manner as conduceth most to the preservation and augmentation of that motion by the help of the Nerves And in animal motion this is the very first Endeavour and found even in the Embrio which while it is in the wombe moveth its limbes with voluntary motion for the avoiding of whatsoever troubleth it or for the pursuing of what pleaseth it And this first Endeavour when it tends towards such things as are known by experience to be pleasant is called APPETITE that is an Approaching and when it shuns what is troublesome AVERSION or Flying from it And little Infants at the beginning and as soon as they are born have appetite to very few things as also they avoid very few by reason of their want of Experience and Memory therefore they have not so great a variety of animal Motion as we see in those that are more grown For it is not possible without such knowledge as is derived from Sense that is without Experience and Memory to know what will prove pleasant or hurtful onely there is some place for conjecture from the looks or aspects of things And hence it is that though they do not know what may do them good or harm yet sometimes they approach and sometimes retire from the same thing as their doubt prompts them But afterwards by accustoming themselves by little and little they come to know readily what is to be pursued and what to be avoided and also to have a ready use of their Nerves and other Organs in the pursuing and avoiding of good and bad Wherefore Appetite and Aversion are the first Endeavours of Animal Motion Consequent to this first Endeavour is the Impulsion into the Nerves and Retraction again of Animal Spirits of which it is necessary there be some Receptacle on place neer the original of the Nerves and this Motion or Endeavour is followed by a swelling and Relaxation of the Muscles and lastly these are followed by Contraction and Extension of the limbes which is Animal Motion 13 The Considerations of Appetites and Aversions are divers For seeing Living Creatures have sometimes Appetite and
of the parts of those plants made an Odorous liquour so also of aire passing through the same plants whilest they are growing are made Odorous aires And thus also it is with the Juices and Spirits which are bred in Living Creatures 16 That Odorous Bodies may be made more Odorous by Contrition proceeds from this that being broken into many parts which are all Odorous the aire which by respiration is drawn from the Object towards the Organ doth in its passage touch upon all those parts and receives their motion Now the aire toucheth the superficies onely and a Body having less superficies whilest it is whole then all its parts together have after it is reduced to powder it follows that the same Odorous Body yeildeth less Smell whilest it is whole then it will do after it is broken into smaller parts And thus much of Smels 17 The Tast follows whose generation hath this difference from that of the Sight Hearing and Smelling that by these we have Sense of remote Objects whereas we Tast nothing but what is contiguous and doth immediately touch either the Tongue or Palate or both From whence it is evident that the cuticles of the Tongue and Palate and the Nerves inserted into them are the first Organ of Tast and because from the concussion of the parts of these there followeth necessarily a concussion of the Pia Mater that the action communicated to these is propagated to the Brain and from thence to the farthest Organ namely the Heart in whose reaction consisteth the nature of Sense Now that Savours as well as Odours doe not onely move the Brain but the Stomack also as is manifest by the loathings that are caused by them both they that consider the Organ of both these Senses will not wonder at all seeing the Tongue the Palate the Nostrils have one and the same continued cuticle derived from the Dura Mater And that Effluviums have nothing to doe in the Sense of Tasting is manifest from this that there is no Tast where the Organ and the Object are not contiguous By what variety of motions the different kinds of Tasts which are innumerable may be distinguished I know not I might with others derive them from the divers figures of those Atomes of which whatsoever may be Tasted consisteth or from the diverse motions which I might by way of Supposition attribute to those Atomes conjecturing not without some likelyhood of truth that such things as tast Sweet have their particles moved with slow circular motion and their figures Spherical which makes them smooth and pleasing to the Organ that Bitter things have circular motion but vehement and their figures full of Angles by which they trouble the Organ and that Sowre things have straight and reciprocal motion and their figures long and small so that they cut and wound the Organ And in like manner I might assigne for the causes of other Tasts such several motions and figures of Atomes as might in probability seem to be the true causes But this would be to revolt from Philosophy to Divination 18 By the Touch we feel what Bodies are Cold or Hot though they be distant from us Others as Hard Soft Rough and Smooth we cannot feel unless they be contiguous The Organ of Touch is every one of those membranes which being continued from the Pia Mater are so diffused throughout the whole Body as that no part of it can be pressed but the Pia Mater is pressed together with it Whatsoever therefore presseth it is felt as Hard or Soft that is to say as more or less Hard. And as for the Sense of Rough it is nothing else but innumerable perceptions of Hard and Hard succeeding one another by short intervals both of time and place For we take notice of Rough and Smooth as also of Magnitude and Figure not onely by the Touch but also by Memory For though some things are touched in one Point yet Rough and Smooth like Quantity and Figure are not perceived but by the Flux of a Point that is to say we have no Sense of them without Time and we can have no Sense of Time without Memory CHAP. XXX Of Gravity 1 A Thick Body doth not contain more Matter unless also more Place then a Thinne 2 That the Descent of Heavy Bodies proceeds not from their own Appetite but from some Power of the Earth 3 The difference of Gravities proceedeth from the difference of the Impetus with which the Elements whereof Heavy Bodies are made do fall vpon the Earth 4 The cause of the Descent of Heavy Bodies 5 In what proportion the Descent of Heavy Bodies is accelerated 6 Why those that Dive do not when they are under Water feel the waight of the Water above them 7 The Waight of a Body that floateth is equal to the Waight of so much Water as would fill the space which the immersed part of the Body takes up within the Water 8 If a Body be Lighter then Water then how big soever that Body be it will float upon any quantity of Water how little soever 9 How Water may be lifted up and forced out of a Vessel by Air. 10 Why a Bladder is Heavier when blown full of aire then when it is empty 11 The cause of the ejection upwards of Heavy Bodies from a Wind-Gun 12 The cause of the ascent of Water in a Weather-glass 13 The cause of motion upwards in Living Creatures 14 That there is in Nature a kind of Body Heavier then Aire which nevertheless is not by Sense distinguishable from it 15 Of the cause of Magnetical vertue 1 IN the 21 Chapter I have defined Thick and Thinne as that place required so as that by Thick was signified a more Resisting Body and by Thinne a Body less Resisting following the custome of those that have before me discoursed of Refraction Now if we consider the true and vulgar signification of those words we shall find them to be Names Collective that is to say Names of Multitude as Thick to be that which takes up more parts of a space given Thinne that which contains fewer parts of the same magnitude in the same space or in a space equal to it Thick therefore is the same with Frequent as a Thick Troop And Thinne the same with Unfrequent as a Thinne Rank Thinne of Houses not that there is more matter in one place then in another equal place but a greater quantity of some named Body For there is not less matter or Body indefinitely taken in a Desert then there is in a City but fewer Houses or fewer Men. Nor is there in a Thick Rank a greater quantity of Body but a greater number of Souldiers then in a Thinne Wherefore the multitude paucity of the parts contained within the same space do constitute Density and Rarity whether those parts be separated by Vacuum or by Aire But the consideration of this is not of any great moment in Philosophy and therefore I let
Metaphysical Empusa not by skirmish but by letting in the light upon her For I am confident if any confidence of a Writing can proceed from the Writers fear circumspection diffidence that in the three former parts of this Book all that I have said is sufficiently demonstrated from Definitions all in the fourth part from Suppositions not absurd But if there appear to your Lordship any thing less fully demonstrated then to satisfie every Reader the cause was this that I professed to write not all to all but some things to Geometricians onely But that your Lordship will be satisfied J cannot doubt There remains the second Section which is concerning Man That part thereof where J handle the Optiques contayning six Chapters together with the Tables of the Figures belonging to them I have already written engravenlying by me above these six years The rest shall as soon as J can be added to it though by the contumelies petty injuries of some unskilful men I know already by experience how much greater thanks will be due then payed me for telling Men the truth of what Men are But the burthen I have taken on me I mean to carry through not striving to appease but rather to revenge my self of Envy by encreasing it For it contents me that I have your Lordships favour which being all you require J acknowledge and for which with my prayers to Almighty God for your Lordships safety J shall to my power be always thankefull London April 23 1655. YOUR LORDSHIPS most humble Servant Thomas Hobbes The Authors Epistle To the Reader THink not courteous Reader that the Philosophy the Elements whereof I am going to set in order is that which makes Philosophers Stones nor that which is found in the Metaphsique Codes But that it is the Natural Reason of Man busily flying up and down among the Creatures bringing back a true report of their Order Causes Effects Philosophy therefore the Childe of the World and your own Mind is within your self perhaps not fashioned yet but like the World its Father as it was in the beginning a thing confused Do therefore as the Statuaries do who by hewing off that which is superfluous do not make but find the Image Or imitate the Creation If you will be a Philosopher in good earnest let your Reason move upon the Deep of your own Cogitations and Experience Those things that lie in Confusion must be set asunder distinguished and every one stampt with its own name set in order that is to say your Method must resemble that of the Creation The order of the Creation was Light Distinction of Day and Night the Firmament the Luminaries Sensible Creatures Man and after the Creation the Commandement Therefore the order of Contemplation will be Reason Definition Space the Starres Sensible Quality Man and after Man is grown up Subjection to Command In the first part of this Section which is entitled Logique I set up the light of Reason In the Second which hath for title the Grounds of Philosophy I distinguish the most common Notions by accurate definition for the avoiding of confusion and obscurity The third part concerns the Expansion of Space that is Geometry The fourth contains the Motion of the Starres together with the doctrine of Sensible Qualities In the second Section if it please God shall be handled Man In the third Section the doctrine of Subjection is handled already This is the Method I followed and if it like you you may use the same for I do but propound not commend to you any thing of mine But whatsoever shall be the Method you will like I would very fain commend Philosophy to you that is to say the study of Wisdome for want of which we have all suffered much dammage lately For even they that study Wealth do it out of love to Wisdome for their Treasures serve them but for a Looking-glass wherin to behold and contemplate their owne Wisdome Nor do they that love to be employed in publike business aime at any thing but place wherein to shew their Wisdome Neither do Voluptuous men neglect Philosophy but onely because they know not how great a pleasure it is to the Mind of Man to be ravished in the vigorous and perpetual embraces of the most beauteous World Lastly though for nothing else yet because the Mind of Man is no less impatient of Empty Time then Nature is of Empty Place to the end you be not forced for want of what to do to be troublesome to men that have business or take hurt by falling into idle Company but have somewhat of your own wherewith to fill up your time I recommend unto you the Study of Philosophy Farewell T. H. The Titles of the CHAPTERS The first Part or Logique CHAP. 1 Of Philosophy CHAP. 2 Of Names CHAP. 3 Of Proportion CHAP. 4 Of Syllogisme CHAP. 5 Of Erring Falsity and Captions CHAP. 6 Of Method The Second Part or The first Grounds of Philosophy CHAP. 7 Of Place and Time CHAP. 8 Of Body and Accident CHAP. 9 Of Cause and Effect CHAP. 10 Of Power and Act. CHAP. 11 Of Identity and Difference CHAP. 12 Of Quantity CHAP. 13 Of Analogisme or the Same Proportion CHAP. 14 Of Straight and Crocked Angle and Figure The third Part Of the Proportions of Motions and Magnitudes CHAP. 15 Of the Nature Properties and divers considerations of Motion and Endeavour CHAP. 16 Of Motion Accelerated and Uniform and of Motion by Concourse CHAP. 17 Of Figures Deficient CHAP. 18 Of the Equation of Straight Lines which the Crooked Lines of Parabolas and other Figures made in imitation of Parabolas CHAP. 19 Of Angles of Incidence and Reflexion equal by supposition CHAP. 20 Of the Dimension of a Circle and the Division of Arches or Angles CHAP. 21 Of Circular Motion CHAP. 22 Of other Variety of Motions CHAP. 23 Of the Center of Equiponderation of Bodies pressing downwards in straight parallel lines CHAP. 24 Of Refraction and Reflexion The fourth Part of Physiques or the Phaenomena of Nature CHAP. 25 Of Sense and Animall Motion CHAP. 26 Of the World and of the Starres CHAP. 27 Of Light Heat and of Colours CHAP. 28 Of Cold Wind Hard Ice Restitution of Bodies bent Diaphanous Lightning and Thunder and of the Heads of Rivers CHAP. 29 Of Sound Odour Savour and Touch. CHAP. 30 Of Gravity COMPUTATION OR LOGIQUE CHAP. I. Of Philosophy 1 The Introduction 2 The Definition of Philosophy explained 3 Ratiocination of the Mind 4 Properties what they are 5 How Properties are known by Generation contrarily 6 The Scope of Philosophy 7 The Utility of it 8 The Subject 9 The Parts of it 10 The Epilogue PHILOSOPHY seems to me to be amongst men now in the same manner as Corn and Wine are said to have been in the world in ancient time For from the beginning there were Vines and Ears of Corn growing here and there in the fields but no care was taken for the
the fourth place which two considerations comprehend that part of Philosophy which is called Physiques And in these four parts is contained whatsoever in Naturall Philosophy may be explicated by Demonstration properly so called For if a Cause were to be rendred of Natural Appearances in special as what are the Motions and Influences of the heavenly Bodies and of their parts the reason hereof must either be drawn from the parts of the Sciences above mentioned or no reason at all will be given but all left to uncertaine conjecture After Physiques we must come to Morall Philosophy in which we are to consider the Motions of the Mind namely Appetite Aversion Love Benevolence Hope Fear Anger Emulation Envy c. what Causes they have and of what they be Causes And the reason why these are to be considered after Physiques is that they have their Causes in Sense and Imagination which are the Subject of Physicall Contemplation Also the reason why all these Things are to be searched after in the order abovesaid is that Physiques cannot be understood except we know first what Motions are in the smallest parts of Bodies nor such Motion of Parts till we know what it is that makes another Body move nor this till we know what Simple Motion will effect And because all Appearance of things to sense is determined and made to be of such and such Quality and Quantity by Compounded Motions every one of which has a certaine degree of Velocity and a certaine and determined way therefore in the first place we are to search out the wayes of Motion simply in which Geometry consists next the wayes of such generated Motions as are manifest and lastly the wayes of internal and invisible Motions which is the Enquiry of Naturall Philosophers And therefore they that study Naturall Philosophy study in vaine except they begin at Geometry and such Writers or Disputers thereof as are ignorant of Geometry do but make their Readers and Hearers lose their time 7 Civill and Morall Philosophy doe not so adhere to one another but that they may be severed For the Causes of the Motions of the Mind are known not onely by Ratiocination but also by the Experience of every man that takes the paines to observe those Motions within himselfe And therefore not only they that have attained the knowledge of the Passions and Perturbations of the Mind by the Syntheticall Method and from the very first Principles of Philosophy may by proceeding in the same way come to the Causes and Necessity of constituting Common-wealths and to get the Knowledge of what is Naturall Right and what are Civill Duties and in every kind of Government what are the Rights of the Commonwealth and all other Knowledge appertaining to Civill Philosophy for this reason that the Principles of the Politiques consist in the Knowledge of the Motions of the Mind and the Knowledge of these Motions from the knowledge of Sense and Imagination but even they also that have not learned the first part of Philosophy namely Geometry and Physiques may notwithstanding attain the Principles of Civill Philosophy by the Analyticall Method For if a Question be propounded as Whether such an Action be Just or Uniust if that Uniust be resolved into Fact against Law and that notion of Law into the Command of him or them that have Coercive Power and that Power be derived from the Wills of Men that constitute such Power to the end they may live in Peace they may at last come to this that the Appetites of Men and the Passions of their Minds are such that unlesse they be restrained by some Power they will alwayes be making warre upon one another which may be known to be so by any mans experience that will but examine his owne Mind And therefore from hence he may proceed by Compounding to the determination of the Justice or Injustice of any propounded Action So that it is manifest by what has been said that the Method of Philosophy to such as seek Science simply without propounding to themselves the Solution of any Particular question is partly Analyticall and partly Syntheticall namely that which proceeds from Sense to the invention of Principles Analyticall and the rest Syntheticall 8 To those that seek the Cause of some certaine and pro pounded Appearance or Effect it happens sometimes that they know not whether the thing whose Cause is sought after be Matter or Body or some Accident of a Body For though in Geometry when the Cause is sought of Magnitude or Proportion or Figure it be certainly known that these things namely Magnitude Proportion and Figure are Accidents yet in Naturall Philosophy where all questions are concerning the Causes of the Phantasmes of sensible things it is not so easie to discern between the things themselves from which those Phantasmes proceed and the Appearances of those things to the sense which have deceived many especially when the Phantasmes have been made by Light For Example a Man that looks upon the Sunne has a certaine shining Idea of â—â—e Magnitude of about a foâ—t over and this he calls the Sunne thougâ—…e know the Sunne to be truly a great deale bigger and in like 〈…〉 the Phantasme of the same thing appears sometimes â—â—und by being 〈…〉 a â—arre off and sometimes square by being neerer Whereupon â—t may well be doubted whether that Phantasme be Maâ—… or some Body Naturall or onely some Accident of a Body in the examination of which doubt we may use this Method The Properties of Matter and Accidents already found out by Us by the Syntheticall Method from their Definitions are to be compared with the Idea we have before us and if it agree with the Properties of Matter or Body then it is a Body otherwise it is an Accident Seeing therefore Matter cannot by any endeavour of ours be either Made or Destroyed or Encreased or Diminished or Moved out of its place whereas that Idea Appeares Vanishes is Encreased and Diminished and Moved hither and thither at pleasure we may certainly conclude that it is not a Body but an Accident onely And this Method is Syntheticall 9 But if there be a doubt made concerning the Subject of any known Accident for this may be doubted sometimes as in the praecedent example doubt may be made in what Subject that Splendor and apparent Magnitude of the Sunne is then our enquiry must proceed in this manner First Matter in Generall must be divided into parts as into Object Medium and the Sentient it selfe or such other parts as seem most conformable to the thing propounded Next these parts are severally to be examined how they agree with the Definition of the Subject and such of them as are not capable of that Accident are to be rejected For example If by any true Ratiocination the Sunne be found to be greater then its apparent Magnitude then that Magnitude is not in the Sunne If the Sunne be in one determined straight line and one determined
which they work is continually altered and changed For example as the Heat of the Fire encreases more and more so also the Effects thereof namely the Heat of such Bodies as are next to it again of such other Bodies as are next to them encreases more more accordingly which is already no litle argument that all Mutation consists in Motion onely the truth whereof shall be further demonstrated in the ninth Article But in this Progress of Causation that is of Action and Passion if any man comprehend in his imagination a part thereof and divide the same into parts the first part or Beginning of it cannot be considered otherwise then as Action or Cause for if it should be considered as Effect or Passion then it would be necessary to consider something before it for its Cause or Action which cannot be for nothing can be before the Beginning And in like manner the last part is considered onely as Effect for it cannot be called Cause if nothing follow it but after the last nothing follows And from hence it is that in all Action the Beginning and Cause are taken for the same thing But every one of the intermediate parts are both Action and Passion and Cause and Effect according as they are compared with the antecedent or subsequent part 7 There can be no Cause of Motion except in a Body Contiguous and Moved For let there be any two Bodies which are not contiguous and betwixt which the intermediate Space is empty or if filled filled with another Body which is at Rest and let one of the propounded Bodies be supposed to be at Rest I say it shall always be at Rest. For if it shall be Moved the Cause of that Motion by the 8th Chapter 19th Article will be in some external Body and therefore if between it and that external Body there be nothing but empty Space then whatsoever the disposition be of that external Body or of the Patient it self yet if it be supposed to be now at Rest we may conceive it wil continue so til it be touched by some other Body but seeing Cause by the Definition is the Aggregate of all such Accidents which being supposed to be present it cannot be conceived but that the Effect will follow those Accidents which are either in external Bodies or in the Patient it self cannot be the Cause of future Motion and in like manner seeing we may conceive that whatsoever is at Rest will still be at Rest though it be touched by some other Body except that other Body be moved therefore in a contiguous Body which is at Rest there can be no Cause of Motion Wherefore there is no Cause of Motion in any Body except it be Contiguous and Moved The same reason may serve to prove that whatsoever is Moved will alwayes be Moved on in the same way and with the same Velocity except it be hindered by some other Contiguous and Moved Body and consequently that no Bodies either when they are at Rest or when there is an interposition of Vacuum can generate or â—â—tinguish or lesson Motion in other Bodies There is one that has written that things Moved are more resisted by things at Rest then by things contrarily Moved for this reason that he conceived Motion not to be so contrary to Motion as Rest. That which deceived him was that the words Rest and Motion are but contradictory Names whereas Motion indeed is not resisted by Rest but by contrary Motion 8 But if a Body work upon another Body at one time and afterwards the same Body work upon the same Body at another time so that both the Agent and Patient and all their parts be in all things as they were and there be no difference except onely in time that is that one Action be former the other later in time it is manifest of it self that the Effects will be Equal and Like as not differing in any thing besides time And as Effects themselves proceed from their Causes so the diversity of them depends upon the diversity of their Causes also 9 This being true it is necessary that Mutation can be nothing else but Motion of the Parts of that Body which is Changed For First we do not say any thing is Changed but that which appears to our Senses otherwise then it appeared formerly Secondly both those Appearances are Effects produced in the Sentient therefore if they be differeÌ„t it is necessary by the preceding article that either some part of the Agent which was formerly at Rest is now Moved and so the Mutation consists in this Motion or some part which was formerly Moved is now otherwise Moved and so also the Mutation consists in this new Motion or which being formerly Moved is now at Rest which as I have shewn above cannot come to pass without Motion and so again Mutation is Motion or lastly it happens in some of these manners to the Patient or some of its parts so that Mutation howsoever it be made will consist in the Motion of the parts either of the Body which is perceived or of the Sentient Body or of both Mutation therefore is Motion namely of the parts either of the Agent or of the Patient which was to be demonstrated And to this it is consequent that Rest cannot be the Cause of any thing nor can any Action proceed from it seeing neither Motion nor Mutation can be caused by it 10 Accidents in respect of other Accidents which precede them or are before them in time upon which they do not depend as upon their Causes are called Contingent Accidents I say in respect of those Accidents by which they are not generated for in respect of their Causes all things come to pass with equal necessity for otherwise they would have no Causes at all which of things generated is not intelligible CHAP. X. Of Power and Act. 1 Power and Cause are the same thing 2 An Act is produced at the same instant in which the Power is Plenary 3 Active and Passive Power are parts onely of Plenary Power 4 An Act when said to be Possible 5 An Act Necessary and Contingent what 6 Active Power consists in Motion 7 Cause Formal and Final what they are 1_COrrespondent to Cause and Effect are POWER and ACT Nay those and these are the same things though for divers considerations they have divers names Forwhensoever any Agent has all those Accidents which are necessarily requisite for the production of some Effect in the Patient then we say that Agent has Power to produce that Effect if it be applyed to a Patient But as I have shewn in the precedent Chapter those Accidents constitute the Efficient Cause and therefore the same Accidents which constitute the Efficient Cause constitute also the Power of the Agent Wherefore the Power of the Agent and the Efficient Cause are the same thing But they are considered with this difference that Cause is so called in respect of the Effect already
of Inclination A B C be an angle of 45 degrees Let C B be produced to the Circumference in D let C E the sine of the angle â— B C be drawn to which let B F be taken equal in the separating line B G. B C E F will therefore be a Parallelogram F E B C that is F E and B G equal Let AG be drawn namely the Diagonal of the Square whose side is B G and it will be as A G to E F so B G to B F so by supposition the density of the Medium in which C is to the density of the Medium in which D is and so also the sine of the angle Refracted to the sine of the angle of Inclination Drawing therefore F D from D the line D H perpendicular to A B produced DH will be the sine of the angle of Inclination And seeing the sine of the angle Refracted is to the sine of the angle of Inclination as the density of the Medium in which is C is to the density of the Medium in which is D that is by supposition as A G is to F E that is as D H is to B G and seeing D H is the sine of the angle of Inclination B G will therefore be the sine of the angle Refracted Wherefore B G will be the Refracted line and lye in the plain separating Superficies which was to be demonstrated Coroll It is therefore manifest that when the Inclination is greater then 45 degrees as also when it is less provided the density be greater it may happen that the Refraction will not enter the thinner Medium at all 8 If a Body fall in a straight line upon another Body and do not penetrate it but be reflected from it the angle of Reflexion will be equal to the angle of Incidence Let there be a Body at A in the 5th figure which falling with straight motion in the line A C upon another Body at C passeth no further but is reflected and let the angle of Incidence be any angle as A C D. Let the straight line C E be drawn making with D C produced the angle E C F equall to the angle A C D and let A D be drawn perpendicular to the straight line D F. Also in the same straight line D F let C G be taken equall to C D and let the perpendicular G E be raised cutting C E in E. This being done the triangles A C D and E C G will be equall and like Let C H be drawn equal and parallel to the straight line A D and let H C be produced indefinitely to I. Lastly let E A be drawn which will passe through H and be parallel and equall to G D. I say the motion from A to C in the straight line of Incidence AC will be reflected in the straight line C E. For the motion from A to C is made by two coefficient or concurrent motions the one in A H parallel to D G the other in A D perpendicular to the same D G of which two motions that in A H workes nothing upon the Body A after it has been moved as farre as C because by supposition it doth not passe the straight line D G whereas the endeavour in A D that is in H C worketh further towards I. But seeing it doth onely presse and not penetrate there will be reaction in H which causeth motion from C towards H and in the mean time the motion in H E remaines the same it was in A H and therefore the Body will now be moved by the concourse of two motions in C H and H E which are equall to the two motions it had formerly in A H and H C. Wherefore it will be carried on in C E. The angle therefore of Reflection will be E C G equall by construction to the angle A C D which was to be demonstrated Now when the Body is considered but as a point it is all one whether the Superficies or line in which the Reflection is made be straight or crooked for the point of Incidence and Reflexion C is as well in the crooked line which toucheth D G in C as in D G it selfe 9 But if we suppose that not a Body be moved but some Endeavour onely be propagated from A to C the Demonstration will neverthelesse be the same For all Endeavour is motion and when it hath reached the Solid Body in C it presseth it and endeavoureth further in C I. Wherefore the reaction will proceed in C H and the endeavour in C H concurring with the endeavour in H E will generate the endeavour in C E in the same manner as in the repercussion of Bodies moved If therefore Endeavour be propagated from any point to the concave Superficies of a Spherical Body the Reflected line with the circumference of a great circle in the same Sphere will make an angle equall to the angle of Incidence For if Endeavour be propagated from A in the 6 fig. to the circumference in B and the center of the Sphere be C and the line C B be drawne as also the Tangent D B E and lastly if the angle F B D be made equall to the angle A B E the Reflexion will be made in the line B F as hath been newly shewn Wherefore the angles which the straight lines A B and F B make with the circumference will also be equall But it is here to be noted that if C B be produced howsoever to G the endeavour in the line G B C will proceed onely from the perpendicular reaction in G B and that therefore there will be no other endeavour in the point B towards the parts which are within the Sphere besides that which tends towards the center And here I put an end to the third part of this Discourse in which I have considered Motion and Magnitude by themselves in the abstract The fourth and last part concerning the Phaenomena of Nature that is to say concerning the Motions and Magnitudes of the Bodies which are parts of the World reall and existent is that which followes PHYSIQVES or the PHAENOMENA of NATVRE CHAP. XXV Of Sense and Animal Motion 1 The connexion of what hath been said with that which followeth 2 The investigation of the nature of Sense and the Definition of Sense 3 The Subject and Object of Sense 4 The Organ of Sense 5 All Bodies are not indued with Sense 6 But one Phantasme at one and the same time 7 Imagination the Remayns of past Sense which also is Memory Of Sleep 8 How Phantasmes succeed one another 9 Dreames whence they proceed 10 Of the Senses their kindes their Organs and Phantasmes proper and common 11 The Magnitude of Images how and by what it is determined 12 Pleasure Pain Appetite and Aversion what they are 13 Deliberation and Will what 1 I Have in the first Chapter defined Philosophy to be Knowledge of Effects acquired
by true Ratiocination from knowledge first had of their Causes and Generation and of such Causes or Generations as may be from former knowledge of their Effects or Appearances There are therefore two Methods of Philosophy One from the Generation of things to their possible Effects and the other from their Effects or Appearances to some possible Generation of the same In the former of these the Truth of the first Principles of our ratiocination namely Definitions is made and constituted by our selves whilest we consent and agree about the Appellations of things And this part I have finished in the foregoing Chapters in which if I am not deceived I have affirmed nothing saving the Definitions themselves which hath not good coherence with the Definitions I have given that is to say which is not sufficiently demonstrated to all those that agree with me in the use of Words and Appellations for whose sake onely I have written the same I now enter upon the other part which is the finding out by the Appearances or Effects of Nature which we know by Sense some wayes and means by which they may be I do not say they are generated The Principles therefore upon which the following discourse depends are not such as we our selves make and pronounce in general terms as Definitions but such as being placed in the things themselves by the Authour of Nature are by us observed in them and we make use of them in single and particular not universal propositions Nor do they impose upon us any necessity of constituting Theoremes their use being onely though not without such general Propositions as have been already demonstrated to shew us the possibility of some production or generation Seeing therefore the Science which is here taught hath its Principles in the Appearances of Nature and endeth in the attayning of some knowledge of Natural causes I have given to this Part the title of PHYSIQUES or the PHAENOMENA of NATURE Now such things as appear or are shewn to us by Nature we call Phaenomena or Appearances Of all the Phaenomena or Appearances which are neer us the most admirable is Apparition it self 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 namely that some Natural Bodies have in themselves the patterns almost of all things and others of none at all So that if the Appearances be the Principles by which we know all other things we must needs acknowledge Sense to be the Principle by which we know those Principles that all the knowledge we have is derived from it And as for the causes of Sense we cannot begin our search of them from any other Phaenomenon then that of Sense it self But you will say by what Sense shall we take notice of Sense I answer by Sense it self namely by the Memory which for some time remains in us of things sensible though they themselves pass away For he that perceiues that he hath perceived remembers In the first place therefore the causes of our Perception that is the causes of those Ideas and Phantasmes which are perpetually generated within us whilest we make use of our Senses are to be enquired into and in what manner their generation proceeds To help which Inquisition we may observe first of all that our Phantasmes or Ideas are not alwayes the same but that new ones appear to us and old ones vanish according as we apply our Organs of Sense now to one Object now to another Wherefore they are generated and perish And from hence it is manifest that they are some change or mutation in the Sentient 2 Now that all Mutation or Alteration is Motion or Endeavour and Endeavour also is Motion in the internal parts of the thing that is altered hath been proved in the 9th Article of the 8th Chapter from this that whilest even the least parts of any Body remain in the same situation in respect of one another it cannot be said that any alteration unless perhaps that the whole Body together hath been moved hath hapned to it but that it both appeareth and is the same it appeared was before Sense therefore in the Sentient can be nothing else but motion in some of the internal parts of the Sentient and the parts so moved are parts of the Organs of Sense For the parts of our Body by which we perceive any thing are those we commonly call the Organs of Sense And so we find what is the Subject of our Sense namely that in which are the Phantasmes and partly also we have discovered the nature of Sense namely that it is some internal Motion in the Sentient I have shewn besides in the 8th Chap. at the 7th Article that no Motion is generated but by a Body contiguous and Moved From whence it is manifest that the immediate cause of Sense or Perception consists in this that the first Organ of Sense is touched and pressed For when the uttermost part of the Organ is pressed it no sooner yeilds but the part next within it is pressed also and in this manner the pressure or Motion is propagated through all the parts of the Organ to the innermost And thus also the pressure of the uttermost part proceeds from the pressure of some more remote Body and so continually till we come to that from which as from its fountain we derive the Phantasme or Idea that is made in us by our Sense And this whatsoever it be is that we commonly call the Object Sense therefore is some internal Motion in the Sentient generated by some internal Motion of the parts of the Object and propagated through all the Media to the innermost part of the Organ By which words I have almost defined what Sense is Moreover I have shewn in the 2d Article of the 15 Chapter that all Resistance is Endeavour opposite to another Endeavour that is to say Reaction Seeing therefore there is in the whole Organ by reason of its own internal natural Motion some Resistance or Reaction against the Motion which is propagated from the Object to the innermost part of the Organ there is also in the same Organ an Endeavour opposite to the Endeavour which proceeds from the Object so that when that Endeavour inwards is the last action in the act of Sense then from the Reaction how little soever the duration of it be a Phantasme or Idea hath its being which by reason the Endeavour is now outwards doth alwayes appear as something situate without the Organ So that now I shall give you the whole Definition of Sense as it is drawn from the explication of the causes thereof and the order of its generation thus SENSE is a Phantasme made by the Reaction and endeavour outwards in the Organ of Sense caused by an Endeavour inwards from the Object remayning for some time more or less 3 The Subject of Sense is the Sentient it self namely some living Creature and we speak more correctly when we say a Living Creature seeth then when we say the Eye seeth The Object is
looking back to the End that is from Consultation it must needs be that seeing in sleep we lose all thought of the End our Phantasmes succeed one another not in that order which tends to any End but as it hapneth and in such manner as Objects present themselves to our Eyes when we look indifferently upon all things before us and see them not because we would see them but because we do not shut our Eyes for then they appear to us without any order at all The second proceeds from this that in the silence of Sense there is no new motion from the Objects and therefore no new Phantasme unless we call that new which is compounded of old ones as a Chimaera a golden Mountain and the like As for the third why a Dream is sometimes as it were the continuation of Sense made up of broken Phantasmes as in men distempered with sickness the reason is manifestly this that in some of the Organs Sense remains and in others it faileth But how some Phantasmes may be revived when all the exteriour Organs are benummed with sleep is not so easily shewn Nevertheless that which hath already been said contains the reason of this also For whatsoever strikes the Pia Mater reviveth some of those Phantasmes that are still in motion in the Brain and when any internal motion of the Heart reacheth that Membrane then the praedominant motion in the Brain makes the Phantasme Now the Motions of the Heart are Appetites and Aversions of which I shall presently speak further And as Appetites and Aversions are generated by Phantasmes so reciprocally Phantasmes are generated by Appetites and Aversions For example Heat in the Heart proceeds from Anger and Fighting and again from Heat in the Heart whatsoever be the cause of it is generated Anger and the Image of an Enemy in Sleep And as Love and Beauty stirre up heat in certain Organs so Heat in the same Organs from whatsoever it proceeds often causeth Desire and the Image of an unresisting Beauty Lastly Cold doth in the same manner generate Feare in those that sleep and causeth them to dream of Ghosts and to have Phantasmes of horrour and danger as Fear also causeth Cold in those that wake so reciprocal are the motions of the Heart and Brain The fourth namely that the things we seem to see and feel in sleep are as clear as in sense it self proceeds from two causes one that having then no sense of things without us that internal motion which makes the Phantasme in the absence of all other impressions is praedominant and the other that the parts of our Phantasms which are decayed and worn out by time are made up with other fictitious parts To conclude when we dream we do not wonder at strange places and the appearances of things unknown to us because Admiration requires that the things appearing be new and unusual which can happen to none but those that remember former appearances whereas in sleep all things appear as present But it is here to be observed that certain Dreams especially such as some men have when they are between sleeping and waking and such as happen to those that have no knowledge of the nature of Dreams and are with all superstitious were not heretofore nor are now accounted Dreams For the Apparitions men thought they saw and the Voices they thought they heard in sleep were not believed to be Phantasmes but things subsisting of themselves and Objects without those that dreamed For to some men as well sleeping as waking but especially to guilty men and in the night and in hallowed places Feare alone helped a little with the stories of such Apparitions hath raised in their minds terrible Phantasmes which have been and are still deceiptfully received for things really true under the names of Ghosts and Incorporeal Substances 10 In most living Creatures there are observed five kinds of Senses which are distinguished by their Organs and by their different kinds of Phantasmes namely Sight Hearing Smell Tast and Touch and these have their Organs partly peculiar to each of them severally and partly common to them all The Organ of Sight is partly animate and partly inanimate The inanimate parts are the three Humours namely the Watry Humour which by the interposition of the Membrane called Uâ—ea the perforation whereof is called the Apple of the Eye is contained on one side by the first concave superficies of the Eye and on the other side by the Ciliary processes and the Coat of the Cristalline humour the Cristalline which hanging in the midst between the Ciliary processes and being almost of Spherical figure and of a thick consistence is inclosed on all sides with its own transparent Coat and the Vitreous or Glassie Humour which filleth all the rest of the Cavity of the Eye and is somewhat thicker then the Watry Humour but thinner then the Cristalline The animate part of the Organ is first the Membrane Choroeides which is a part of the Pia Mater saving that it is covered with a Coat derived from the marrow of the Optique Nerve which is called the Retina and this Choroeides seeing it is part of the Pia Mater is continued to the beginning of the Medulla Spinalis within the Scull in which all the Nerves which are within the Head have their roots Wherefore all the Animal Spirits that the Nerves receive enter into them there for it is not imaginable that they can enter into them any where else Seeing therefore Sense is nothing else but the action of Objects propagated to the furthest part of the Organ and seeing also that Animal Spirits are nothing but Vital Spirits purified by the Hart and carried from it by the Arteries it follows necessarily that the action is derived from the Heart by some of the Arteries to the roots of the Nerves which are in the Head whether those Arteries be the Plexus Retiformis or whether they be other Arteries which are inserted into the substance of the Brain And therefore those Arteries are the Complement or the remaying part of the whole Organ of Sight And this last part is a common Organ to all the Senses wheras that which reacheth from the Eie to the roots of the Nerves is proper onely to Sight The proper Organ of Hearing is the Tympanum of the Eare and its own Nerve from which to the Heart the Organ is Common So the proper Organs of Smel Tast are Nervous Membranes in the Palate and Tongue for the Taste and in the Nostrils for the Smell and from the roots of those Nerves to the Heart all is common Lastly â—he proper Organ of Touch are Nerves and Membranes dispersed through the whole Body which Membranes are derived from the root of the Nerves And all things else belonging alike to all the Senses seem to be administred by the Arteries and not by the Nerves The proper Phantasme of Sight is Light and under this name of Light Colour also which is
will remain no cause at all why the water should be forced out Wherefore the assertion of Vacuum is repugnant to the very experiment which is here brought to establish it Many other Phaenomena are usually brought for Vacuum as those of Weather-glasses Aeolipiles Wind-guns c. Which would all be very hard to be salved unless water be penetrable by aire without the intermixture of empty space But now seeing aire may with no great endeavour pass through not onely water but any other fluid Body though never so stubborn as Quicksilver these Phaenomena prove nothing Nevertheless it might in reason be expected that he that would take away Vacuum should without Vacuum shew us such causes of these Phaenomena as should be at least of equal if not greater probability This therefore shall be done in the following discourse when I come to speak of these Phaenomena in their proper places But first the most general Hypotheses of natural Philosophy are to be premised And seeing that Suppositions are put for the true Causes of apparent Effects every Supposition except such as be absurd must of necessity consist of some supposed possible Motion for Rest can never be the Essicient Cause of any thing Motion supposeth Bodies Moveable of which there are three kinds Fluid Consistent and mixt of both Fluid are those whose parts may by very weak endeavonr be separated from one another and Consistent those for the separation of whose parts greater force is to be applyed There are therefore degrees of Consistency which degrees by comparison with more or less Consistent have the names of Hardness or Softness Wherefore a Fluid Body is alwayes divisible into Bodies equally Fluid as Quantity into Quantities and Soft Bodies of whatsoever degree of Softness into Soft Bodies of the same degree And though many men seem to conceive no other difference of Fluidity but such as ariseth from the different magnitudes of the parts in which Sense Dust though of Diamonds may be called Fluid Yet I understand by Fluidity that which is made such by Nature equally in every part of the Fluid Body not as Dust is Fluid for so a House which is falling in pieces may be called Fluid but in such manner as Water seems Fluid and to divide it self into parts perpetually Fluid And this being well understood I come to my Suppositions 5 First therefore I suppose That the Immense Space which we call the World is the Aggregate of all Bodies which are either Consistent Visible as the Earth and the Starres or Invisible as the small Atomes which are disseminated through the whole space between the Earth and the Stars and lastly that most Fluid Aether which so fils all the rest of the Universe as that it leaves in it no empty place at all Secondly I suppose with Copernicus That the greater Bodies of the World which are both consistent and permanent have such order amongst themselves as that the Sunne hath the first place Mercury the second Venus the third The Earth with the Moon going about it the fourth Mars the fifth Jupiter with his Attendants the sixth Saturne the seventh and after these the Fixed Starres have their several distances from the Sunne Thirdly I suppose That in the Sunne the rest of the Planets there is and alwayes has been a Simple Circular Motion Fourthly I suppose That in the Body of the Aire there are certain other Bodies intermingled which are not Fluid but withal that they are so small that they are not preceptible by Sense and that these also have their proper Simple Motion and are some of them more some less hard or consistent Fifthly I suppose with Kepler That as the distance between the Sunne and the Earth is to the distance between the Moon and the Earth so the distance between the Moon and the Earth is to the Semidiameter of the Earth As for the Magnitude of the Circles and the Times in which they are described by the Bodies which are in them I will suppose them to be such as shall seem most agreeable to the Phaenomena in question 6 The causes of the different Seasons of the Year and of the several variations of Dayes and Nights in all the parts of the superficies of the Earth have been demonstrated first by Copernicus and since by Kepler Galilaeus and others from the supposition of the Earths diurnal revolution about its own Axis together with its Annual motion about the Sunne in the Ecliptick according to the order of the Signes and thirdly by the annual revolution of the same Earth about its own center contrary to the order of the Signs I suppose with Copernicus That the diurnal revolution is from the motion of the Earth by which the Aequinoctial Circle is described about it And as for the other two annual motions they are the efficient cause of the Earths being carried about in the Ecliptick in such manner as that its Axis is alwayes kept parallel to it self Which parallelisme was for this reason introduced lest by the Earths annual revolution its Poles should seem to be necessarily carried about the Sunne contrary to experience I have in the 10th Artic. of the â—â—th Chap. demonstrated from the supposition of Simple Circular Motion in the Sun that the Earth is so carried about the Sunne as that its Axis is thereby kept always parallel to it self Wherefore from these two supposed motions in the Sunne the one Simple Circular Motion the other Circular Motion about its owns Center it may be demonstrated that the Year hath both the same variations of Dayes and Nights as have been demonstrated by Copernicus For if the Circle abcd in the 3d Figure be the Ecliptick whose Center is e and Diameter aec and the Earth be placed in a the Sunne be moved in the little Circle fghi namely according to the order f g h i it hath been demonstrated that a Body placed in a will be moved in the same order through the points of the Ecliptick a b c d and will alwayes keep its Axis parallel to its self But if as I have supposed the Earth also be moved with Simple Circular Motion in a plain that passeth through a cutting the plain of the Ecliptick so as that the common section of both the plains be in ac thus also the Axis of the Earth will be kept alwayes parallel to it self For let the Center of the Earth be moved about in the Circumference of the Epicycle whose Diameter is lak which is a part of the straight line lac Therefore lak the Diameter of the Epicycle passing through the Center of the Earth will be in the plain of the Ecliptick Wherefore seeing that by reason of the Earths Simple Motion both in the Ecliptick and in its Epicycle the straight line lak is kept alwayes parallel to it self every other straight line also taken in the Body of the Earth and consequently its Axis will in like manner be kept alwayes parallel
be done 16 Granting that the Clouds may be frozen it is no wonder if the Moon have been seen eclipsed at such time as she hath been almost two degrees above the Horizon the Sunne at the same time appearing in the Horizon for such an Eclipse was observed by Mestline at Tubing in the year 1590. For it might happen that a frozen Cloud was then interposed between the Sunne and the Eie of the Observer And if it were so the Sunne which was then almost two Degrees below the Horizon might appear to be in it by reason of the passing of his Beams through the Ice And it is to be noted that those that attribute such refractions to the Atmosphere cannot attribute to it so great a refraction as this Wherefore not the Atmosphere but either Water in a continued Body or else Ice must be the cause of that refraction 17 Again granting that there may be Ice in the Clouds it will be no longer a wonder that many Sunnes have sometimes appeared at once For Looking-glasses may be so placed as by reflections to shew the same object in many places And may not so many frozen Clouds serve for so many Looking-glasses and may they not be fitly disposed for that purpose Besides the number of Appearances may be encreased by refractions also and therefore it would be a greater wonder to me if such Phaenomena as these should never happen And were it not for that one Phaenomenon of the new Starre which was seen in Cassiopaea I should think Comets were made in the same manner namely by Vapours drawn not onely from the Earth but from the rest of the Planets also and congeled into one continued Body For I could very well from hence give a reason both of their Haire and of their motions But seeing that Starre remained sixteen whole moneths in the same place amongst the fixed Starres I cannot believe the matter of it was Ice Wherefore I leave to others the disquisition of the cause of Comets concerning which nothing that hath hitherto been published 〈…〉 the bare Histories of them is worth considering 18 The Heads of Rivers may be deduced from Rain-water or from melted Snowes very easily but from other causes very hardly or not at all For both Rain-water and melted Snowes run down the descents of Mountains and if they descend onely by the outward Superficies the Showres or Snowes themselves may be accounted the Springs or Fountains but if they enter the Earth descend within it then wheresoever they break out there are their Springs And as these Spings make small streams so many small streams running together make Rivers Now there was never any Spring foūd but where the Water w ch flowed to it was either further or at least as farre from the center of the Earth as the Spring it self And whereas it has bin objected by a great Philosopher that in the top of Mount-Cenis which parts Savoy from Piemont there Springs a River which runs down by Susa it is not true For there are above that River for two miles length very high hils on both sides which are almost perpetually covered with Snow from which innumerable little streams running down do manifestly supply that River with water sufficient for its magnitude CHAP. XXIX Of Sound Odour Savour and Touch 1 The definition of Sound and the distinctions of Sounds 2 The cause of the degrees of Sounds 3 The difference between Sounds Acute and Grave 4 The difference between Clear and Hoarse Sounds whence 5 The Sound of Thunder and of a Gunne whence it proceeds 6 Whence it is that Pipes by blowing into them have a clear Sound 7 Of Reflected Sound 8 From whence it is that Sound is Uniform and Lasting 9 How Sound may be helped aud hindered by the Wind. 10 Not onely Aire but other Bodies how hard soever they be conveigh Sound 11 The causes of Grave and Acute Sounds and of Concent 12 Phaenomena for Smelling 13 The first Organ and the generation of Smelling 14 How it is helped by Heat and by Wind. 15 Why such Bodies are least smelt which have least intermixture of Aire in them 16 Why Odorous things become more Odorous by being bruised 17 The first Organ of Tasting and why some Savours cause Nauseousness 18 The first Organ of Feeling and how we come to the knowledge of such Objects as are common to the Touch and other Senses SOUND is Sense generated by the action of the Medium when its motion reacheth the Eare and the rest of the Organs of Sense Now the motion of the Medium is not the Sound it self but the cause of it For the Phantasme which is made in us that is to say the Reaction of the Organ is properly that which we call Sound The principal distinctions of Sounds are these First that one Sound is stronger another Weaker Secondly that one is more Grave another more Acute Thirdly that one is Clear another Hoarse Fourthly that one is Primary another Derivative Fifthly that one is Uniform another not Sixthly that one is more Durable another less Durable Of all which distinctions the members may be subdistinguished into parts distinguishable almost infinitely For the variety of Sounds seems to be not much less then that of Colours As Vision so Hearing is generated by the motion of the Medium but not in the same manner For Sight is from Pressure that is from an Endeavour in which there is no perceptible progression of any of the parts of the Medium but one part urging or thrusting on an other propagateth that action successively to any distance whatsoever whereas the motion of the Medium by which Sound is made is a Stroke For when we Hear the Drumme of the Eare which is the first Organ of Hearing is stricken and the Drumme being stricken the Pia Mater is also shaken and with it the Arteries which are inserted into it by which the action being propagated to the Heart it self by the reaction of the Heart a Phantasm is made which we call Sound and because the reaction tendeth outwards we think it is without 2 And seeing the effects produced by Motion are greater or lesse not onely when the Velocity is greater or less but also when the Body hath greater or less Magnitude though the Velocity be the same a Sound may be greater or lesse both these wayes And because neither the greatest nor the least Magnitude or Velocity can be given it may happen that either the motion may be of so small velocity or the Body it self of so small magnitude as to produce no Sound at all or either of them may be so great as to take away the Faculty of Sense by hurting the Organ From hence may be deduced possible causes of the strength and weakness of Sounds in the following Phaenomena The first whereof is this That if a man speak through a Trunk which hath on end applyed to the mouth of the Speaker and the other to the eare of the
of the cause of Smels I shall make use of the evidence of these following Phaenomena First that Smelling is hindred by Cold and helped by Heat Secondly that when the Wind bloweth from the Object the Smel is the stronger and contrarily when it bloweth from the Sentient towards the Object the weaker both which Phaenomena are by experience manifestly found to be true in Doggs which follow the track of Beasts by the Sent. Thirdly that such Bodies as are less pervious to the fluid Medium yeild less Smell then such as are more pervious as may be seen in Stones and Metals which compared with Plants and Living Creatures and their Parts Fruits and Excretions have very little or no Smell at all Fourthly that such Bodies as are of their own nature Odorous become yet more Odorous when they are bruised Fifthly that when the breath is stopped at least in Men nothing can be Smelt Sixthly that the sense of Smelling is also taken away by the stopping of the Nostrils though the mouth be left open 13 By the fourth and fifth Phaenomenon it is manifest that the first and immediate Organ of Smelling is the innermost cuticle of the Nostrils and that part of it which is below the passage common to the Nostrils and the Palate For when we draw breath by the Nostrils we draw it into the Lungs That breath therefore which conveighs Smels is in the way which passeth to the Lungs that is to say in that part of the Nostrils which is below the passage through which the breath goeth For nothing is Smelt neither beyond the passage of the breath within nor at all without the Nostrils And seeing that from different Smels there must necessarily proceed some mutation in the Organ and all mutation is motion it is therefore also necessary that in Smelling the parts of the Organ that is to say of that internal cuticle and the nerves that are inserted into it must be diversly moved by different Smels And seeing also that it hath been demonstrated that nothing can be moved but by a Body that is already moved and contiguous and that there is no other Body contiguous to the internal membrane of the nostrils but breath that is to say attracted aire and such little solid invisible Bodies if there be any such as are intermingled with the aire it follows necessarily that the cause of Smelling is either the motion of that pure aire or aethereal Substance or the motion of those small Bodies But this motion is an effect proceding from the Object of Smell and therefore either the whole Object it self or its several parts must necessarily be moved Now we know that Odorous Bodies make Odour though their whole bulk be not moved Wherefore the cause of Odour is the motion of the invisible parts of the Odorous Body And these invisible parts do either go out of the Object or else retaining their former situation with the rest of the parts are moved together with them that is to say they have simple and invisible motion They that say there goes something out of the Odorous Body call it an Effluvium which Effluvium is either of the aethereal substance or of the small Bodies that are intermingled with it But that all variety of Odours should proceed from the Effluviums of those small Bodies that are intermingled with the aethereal substance is altogether incredible for these considerations First that certain Unguents though very little in quantity do nevertheless send forth very strong Odours not onely to a great distance of place but also to a great continuance of time and are to be Smelt in every point both of that place and time so that the parts issued out are sufficient to fil ten thousand times more space then the whole Odorous Body is able to fill which is impossible Secondly that whether that issuing out be with straight or with crooked motion if the same quantity should flow from any other Odorous Body with the same motion it would follow that all Odorous Bodies would yeild the same Smell Thirdly that seeing those Effluviums have great Velocity of motion as is manifest from this that noysome Odours proceeding from caverns are presently Smelt at a great distance it would follow that by reason there is nothing to hinder the passage of those Effluviums to the Organ such motion alone were sufficient to cause Smelling Which is not so for we cannot Smell at all unless we draw in our breath through our Nostrils Smelling therefore is not caused by the Effluvium of Atomes nor for the same reason is it caused by the Effluvium of aethereal substance for so also we should Smell without the drawing in of our breath Besides the aethereal substance being the same in all Odorous Bodies they would always affect the Organ in the same manner and consequently the Odours of all things would be like It remains therefore that the cause of Smelling must consist in the Simple motion of the parts of Odorous Bodies without any efflux or diminution of their whole substance And by this motion there is propagated to the Organ by the intermediate aire the like motion but not strong enough to excite Sense of it self without the attraction of aire by respiration And this is a possible cause of Smelling 14 The cause why Smelling is hindred by Cold and helped by Heat may be this that Heat as hath been shewn in the 21 Chapter generateth Simple motion and therefore also wheresoever it is already there it will encrease it and the cause of Smelling being encreased the Smell it self will also be encreased As for the cause why the Wind blowing from the Object makes the Smell the stronger it is all one with that for which the attraction of aire in respiration doth the same For he that draws in the aire next to him draws with it by succession that aire in which is the Object Now this motion of the aire is Wind and when another Wind bloweth from the Object will be encreased by it 15 That Bodies which cōtain the least quantity of air as Stones and Metals yeild less Smell then Plants and Living Creatures the cause may be that the motion which causeth Smelling is a motion of the fluid parts onely which parts if they have any motion from the hard parts in which they are contained they communicate the same to the open aire by which it is propagated to the Organ Where therefore there are no fluid parts as in Metals or where the fluid parts receive no motion from the hard parts as in Stones which are made hard by accretion there can be no Smell And therefore also the Water whose parts have little or no motion yeildeth no Smell But if the same Water by Seeds and the heat of the Sunne be together with particles of Earth raised into a Plant and be afterwards pressed out again it will be Odorous as Wine from the Vine And as Water passing through plants is by the motion
the Earth was before the Wind it self and if the Earth were Moved before the Wind was made then the Wind could not be the cause of the Earths revolution but if the Sunne were Moved and the Earth stand still then it is manifest the Earth might remain Unmoved notwithstanding that Wind and therefore that motion was not made by the Cause which he alledgeth But Parallogismes of this kind are very frequent among the Writers of Physiques though none can be more elaborate then this in the Example given 19 It may to some men seem pertinent to treat in this place of that Art of the Geometricians which they call Logistica that is the Art by which from supposing the thing in question to be true they proceed by Ratiocination till either they come to something knowne by which they may demonstrate the truth of the thing sought for or to something which is impossible from whence they collect that to be false which they supposed true But this Art cannot be explicated here for this reason that the Method of it can neither be practised nor understood unlesse by such as are well versed in Geometry and among Geometricians themselves they that have most Theoremes in readiness are the most ready in the use of this Logistica so that indeed it is not a distinct thing from Geometry it selfe for there are in the Method of it three parts the first whereof consists in the finding out of Equality betwixt known and unknown things which they call Equation and this Equation cannot be found out but by such as know perfectly the Nature Properties and Transpositions of Proportion as also the Addition Substraction Multiplication and Division of Lines and Superficies and the Extraction of Roots which are the parts of no meane Geometrician The Second is when an Equation is found to be able to judge whether the Truth or Falsity of the Question may be deduced from it or no which yet requires greater Knowledge And the third is when such an Equation is found as is fit for the solution of the Question to know how to Resolve the same in such manner that the Truth or Falsity may thereby manifestly appeare which in hard questions cannot be done without the Knowledge of the Nature of Crooked-lined Figures but he that understands readily the Nature and Properties of these is a Compleat Geometrician It happens besides that for the finding out of Equations there is no certaine Method but he is best able to do it that has the best Naturall Wit THE FIRST GROVNDS OF PHILOSOPHY CHAP. VII Of Place and Time 1 Things that have no existence may neverthelesse be under stood and computed 2 What is space 3 Time 4 Part. 5 Division 6 One 7 Number 8 Composition 9 The Whole 10 Spaces and Times Contiguous and Continuall 11 Beginning End Way Finite Infinite 12 What is Infinite in Power Nothing Infinite can be truly said to be either Whole or One Nor Infinite Spaces or Times Many 13 Division proceeds not to the Least 1 IN the Teaching of Naturall Philosophy I cannot begin better as I have already shewn then from Privation that is from feigning the World to be annihilated But if such annihilation of all things be supposed it may perhaps be asked what would remain for any Man whom onely I except from this Universal annihilation of things to consider as the Subject of Philosophy or at all to reason upon or what to give Names unto for Ratiocinations sake I say therefore there would remain to that Man Ideas of the World and of all such Bodies as he had before their annihilation seen with his eies or perceived by any other Sense that is to say the Memory and Imagination of Magnitudes Motions Sounds Colours c. as also of their order parts All w ch things though they be nothing but Ideas Phantasms hapning internally to him that imagineth yet they will appear as if they were externall and not at all depending upon any power of the Mind And these are the things to which he would give Names and substract them from and compound them with one another For seeing that after the destruction of all other things I suppose Man still remaining and namely that he thinkes imagines and remembers there can be nothing for him to thinke of but what is Past Nay if we do but observe diligently what it is we doe when we consider and reason we shall find that though all things be still remaining in the world yet we compute nothing but our own Phantasmes For when we calculate the magnitude and motions of Heaven or Earth we doe not ascend into Heaven that we may divide it into parts or measure the motions thereof but we doe it sitting still in our Closets or in the Darke Now things may be considered that is be brought into Account either as internal Accidents of our Mind in which manner we consider them when the question is about some Faculty of the Mind or as Species of external things not as really existing but appearing onely to exist or to have a Being without Us. And in this manner we are now to consider them 2 If therefore we remember or have a Phantasme of any thing that was in the world before the supposed annihilation of the same and consider not that the thing was such or such but onely that it had a Being without the Mind we have presently a Conception of that we call Space an Imaginary Space indeed because a meere Phantasme yet that very thing which all men call so For no man calls it Space for being already filled but because it may be filled nor does any man think Bodies carry their Places away with them but that the same Space contains sometimes one sometimes another Body which could not be if Space should alwayes accompany the Body which is once in it And this is of it selfe so manifest that I should not thinke it needed any explaining at all but that I finde Space to be falsely defined by certaine Philosophers who inferre from thence One that the world is Infinite for taking Space to be the Extension of Bodies and thinking Extension may encrease continually he inferres that Bodies may be infinitely Extended and Another from the same Definition concludes rashly that it is impossible even to God himselfe to create more Worlds then one for if another World were to be created he sayes that seeing there is nothing without this world and therefore according to his Definition no Space that new world must be placed in nothing but in nothing nothing can be placed which he affirms onely without shewing any reason for the same whereas the contrary is the truth for more cannot be put into a Place allready filled so much is Empty Space fitter then that which is Full for the receiving of new Bodies Having therefore spoken thus much for these mens sakes and for theirs that assent to them I return to my purpose and define Space thus
two Times betwixt which there is no other Time are called IMMEDIATE A B C as AB BC. And any two Spaces as well as Times are said to be CONTINUALL when they have one common part A B C D as AC BD where the part BC is common and more Spaces and Times are Continual when every two which are next one another are Continual 11 That Part which is between two other Parts is called a MEAN that which is not between two other parts an EXTREME And of Extremes that which is first reckoned is the BEGINNING and that which last the END and all the Means together taken are the WAY Also Extreme Parts and Limits are the same thing And from hence it is manifest that Beginning and End depend upon the order in which we number them and that to Terminate or Limit Space and Time is the same thing with imagining their Beginning and End as also that every thing is FINITE or INFINITE acording as we imagine or not imagine it Limited or Terminated every way and that the Limits of any Number are Unities and of these that which is the first in our Numbering is the Beginning and that which we number last is the End When we say Number is Infinite we mean only that no Number is expressed for when we speak of the Numbers Two Three a Thousand c. they are always Finite But when no more is said but this Number is Infinite it is to be understood as if it were said this Name Number is an Indefinite Name 12 Space or Time is said to be Finite in Power or Terminable when there may be assigned a Number of finite Spaces or Times as of Paces or Hours than which there can be no greater Number of the same measure in that Space or Time and Infinite in Power is that Space or Time in which a greater Number of the said Paces or Hours may be assigned than any Number that can be given But we must note that although in that Space or Time which is Infinite in Power there may be numbered more Paces or Hours then any number that can be assigned yet their number will alwayes be Finite for every Number is Finite And therefore his Ratiocination was not good that undertaking to prove the World to be Finite reasoned thus If the world be Infinite then there may be taken in it some Part which is distant from us an Infinite number of Paces But no such Part can be taken wherefore the world is not infinite because that Consequence of the Major Proposition is false for in an Infinite space whatsoever we take or design in our Mind the distance of the same from us is a Finite space for in the very designing of the place thereof we put an End to that space of whch we our selves are the Beginning and whatsoever any man with his Mind cuts off both wayes from Infinite he determines the same that is he makes it Finite Of Infinite Space or Time it cannot be said that it is a Whole or One not a Whole because not compounded of Parts for seeing Parts how many soever they be are severally Finite they will also when they are all put together make a whole Finite Nor One because nothing can be said to be One except there be Another to compare it with but it cannot be conceived that there are two Spaces or two Times Infinite Lastly when we make question whether the World be Finite or Infinite we have nothing in our Minde answering to the Name World for whatsoever we Imagine is therefore Finite though our Computation reach the fixed Stars or the ninth or tenth nay the thousanth Sphere The meaning of the Question is this onely whether God has actually made so great an Addition of Body to Body as we are able to make of Space to Space 13 And therefore that which is commonly said that Space and Time may be divided Infinitely is not to be so understood as if there might be any Infinite or Eternal Division but rather to be taken in this sense Whatsover is Divided is divided into such Parts as may again be Divided or thus The Least Divisible thing is not to be given or as Geometricians have it No Quantity is so small but a Less may be taken which may easily be demonstrated in this manner Let any Space or Time that which was thought to be the Least Divisible be divided into two equal Parts A and B. I say either of them as A may be divided again For suppose the Part A to be contiguous to the Part B of one side and of the other side to some other Space equal to B. This whole Space therefore being greater then the Space given is divisible Wherefore if it be divided into two equal Parts the Part in the middle which is A will be also divided into two equal Parts and therefore A was Divisible CHAP. VIII Of Body and Accident 1 Body defined 2 Accident defined 3 How an Accident may be understood to be in its subject 4 Magnitude what it is 5 Place what it is and that it is Immoveable 6 What is Full and Empty 7 Here There Somewhere what they signifie 8 Many Bodies cannot be in One place nor One Body in Many places 9 Contiguous and Continual what they are 10 The definition of Motion No Motion intelligible but with Time 11 What it is to be at Rest to have been Moved and to be Moved No Motion to be conceived without the conception of Past and Future 12 A Point a Line Superficies and Solid what they are 13 Equal Greater and Lesse in Bodies and Magnitudes what they are 14 One and the same Body has alwayes one and the the same Magnitude 15 Velocity what it is 16 Equal Greater and Lesse in Times what they are 17 Equal Greater and Lesse in Velocity what 18 Equal Greater and Lesse in Motion what 19 That which is at Rest will alwayes be at Rest except it be Moved by some external thing and that which is Moved will alwayes be Moved unless it be hindered by some external thing 20 Accidents are Generated and Destroyed but Bodies not so 21 An Accident cannot depart from its Subject 22 Nor be Moved 23 Essence Form and Matter what they are 24 First Matter what 25 That the whole is greater then any Part thereof why demonstrated 1 HAving understood what Imaginary Space is in which we supposed nothing remaining without us but all those things to be destroyed that by existing heretofore left Images of themselves in our Minds let us now suppose some one of those things to be placed again in the World or created anew It is necessary therefore that this new created or replaced thing do not onely fill some part of the Space above-mentioned or be coincident and coextended with it but also that it have no dependance upon our thought And this is that which for the Extension of it we commonly call Body and because it depends
as is said above in the seventh Article From what is above demonstrated namely that whatsoever is Moved has also been Moved and will be Moved this also may be collected that there can be no conception of Motion without conceiving Past and Future time 12 Though there be no Body which has not some Magnitude yet if when any Body is moved the Magnitude of it be not at all considered the way it makes it called a LINE or one single Dimension the Space through which it passeth is called LENGTH and the Body it self a POINT in which sense the Earth is called a Point and the Way of its yearly Revolution the Ecliptick Line But if a Body which is Moved be considered as long and be supposed to be so Moved as that all the several parts of it be understood to make several Lines then the Way of every part of that Body is called BREADTH and the Space which is made is called SUPERFICIES consisting of two Dimensions one whereof to every several part of the other is applyed whole Again if a Body be considered as having Superficies and be understood to be so Moved that all the several parts of it describe several Lines then the Way of every part of that Body is called THICKNESS or DEPTH and the Space which is Made is called SOLID consisting of three Dimensions any two whereof are applyed whole to every several part of the third But if a Body be considered as Solid then it is not possible that all the several parts of it should describe several lines for what way soever it be Moved the way of the following part will fall into the way of the part before it so that the same Solid will still be made which the formost Superficies would have made by it self And therefore there can be no other Dimension in any Body as it is a Body then the three which I have now described though as it shall be shewed hereafter Velocity which is Motion according to Length may be being applyed to all the parts of a Solid make a Magnitude of Motion consisting of four Dimensions as the goodness of Gold computed in all the parts of it makes the Price and Value thereof 13 Bodies how many soever they be that can fill every one the place of every one are said to be EQUAL every one to every other Now one Body may fill the same Place which another Body filleth though it be not of the same Figure with that other Body if so be that it may be understood to be reducible to the same Figure either by Flexion or Transposition of the parts And One Body is GREATER then another Body when a part of that is equal to all this and LESSE when all that is equal to a part of this Also Magnitudes are Equal or Greater or Lesser then one another for the same consideration namely when the Bodies of which they are the Magnitudes are either Equal or Greater or Lesse c. 14 One and the same Body is alwayes of one and the same Magnitude For seeing a Body and the Magnitude and Place thereof cannot be comprehended in the Minde otherwise then as they are Coincident if any Body be understood to be at Rest that is to remain in the same Place during some time and the Magnitude thereof be in one part of that time Greater and in another part Lesse that Bodies Place which is one and the same will be coincident sometimes with Greater sometimes with Lesse Magnitude that is the same Place will be greater and lesse then it self which is impossible But there would be no need at all of Demonstrating a thing that is in it self so manifest if there were not some whose opinion concerning Bodies and their Magnitudes is that a Body may exist separated from its Magnitude and have greater or lesse Magnitude bestowed upon it making use of this Principle for the explication of the nature of Rarum and Densum 15 Motion in as much as a certain Length may in a certain Time be transmitted by it is called VELOCITY or Swiftness c. For though Swift be very often understood with relation to Slower or less Swift as Great is in respect of Less yet nevertheless as Magnitude is by Philosophers taken absolutely for Extension so also Velocity or Swiftness may be put absolutely for Motion accord ing to Length 16 Many Motions are said to be made in Equal Times when every one of them begins and ends together with some other Motion or if it had begun together would also have ended together with the same For Time which is a Phantasme of Mo tion cannot be reckoned but by some exposed Motion as in Dials by the Motion of the Sun or of the Hand and if two or more Motions begin and end with this Motion they are said to be made in equal times from whence also it is easie to understand what it is to be moved in Greater or Longer time in lesse time or not so long namely that that is longer Moved which beginning with another ends later or ending together began sooner 17 Motions are said to be Equally Swift when Equal lengths are transmitted in Equal times and Greater Swiftness is that wherein Greater length is passed in Equal time or Equal length in less time Also that Swiftness by which Equal lengths are passed in Equal parts of time is called Uniform Swiftness or Motion and of Motions not Uniform such as become Swifter or Slower by equal Increasings or Decreasings in equal parts of time are said to be Accelerated or Retarded Uniformly 18 But Motion is said to be Greater Lesse and Equal not onely in regard of the Length which is transmitted in a certain time that is in regard of Swiftness onely but of Swiftness applyed to every smallest particle of Magnitude For when any Body is Moved every part of it is also Moved and supposing the parts to be halves the Motions of those halves have their Swiftness equal to one another and severally equal to that of the Whole but the Motion of the Whole is equal to those two Motions either of which is of equal Swiftness with it and therefore it is one thing for two Motions to be Equal to one another another thing for them to be Equally Swift And this is manifest in two Horses that draw abreast where the Motion of both the Horses together is of Equal Swiftness with the Motion of either of them singly but the Motion of both is Greater then the Motion of one of them namely Double Wherefore Motions are said to be simply Equal to one another when the Swiftness of one computed in every part of its Magnitude is Equal to the Swiftness of the other cōputed also in every part of its Magnitude Greater then one another when the Swiftness of one computed as above is Greater then the Swiftness of the other so computed and Lesse when Lesse Besides the Magnitude of Motion computed in this
other then an Efficient Cause A Final Cause has no place but in such things as have Sense and Will and this also I shall prove hereafter to be an Efficient Cause CHAP. XI Of Identity and Difference 1 What it is for one thing to Differ from another 2 To Differ in Number Magnitude Species and Genus what 3 What is Relation Proportion and Relatives 4 Proportionals what 5 The Proportion of Magnitudes to one another wherein it consists 6 Relation is no new Accident but one of those that were in the Relative before the Relation or Comparison was made Also the Causes of Accidents in the Correlatives are the Cause of Relation 7 Of the Beginning of Individuation 1_HItherto I have spoken of Body simply and of Accidents common to all Bodies as Magnitude Motion Rest Action Passion Power Possible c. And I should now descend to those Accidents by which one Body is distinguished from anoâ—â—er but that it is first to be declared what it is to be Distinct and not Distinct namely what are the SAME and DIFFERENT for this also is common to all Bodies that they may be distinguished and differenced from one another Now two Bodies are said to Differ from one another when something may be said of one of them which cannot be said of the other at the same time 2 And first of all it is manifest that no Two Bodies are the Same for seeing they are Two they are in two places at the same time as that which is the Same is at the same time in one and the same place All Bodies therefore differ from one another in Number namely as One and Another so that the Same and different in Number are Names opposed to one another by Contradiction In Magnitude Bodies differ when One is greater then Another as a Cubit long and two Cubits long of two pound weight and of three pound weight And to these Equals are opposed Bodies which differ more then in Magnitude are called Unlike and those which differ onely in Magnitude Like Also of Unlike Bodies some are said to differ in the Species other in the Genus in the Species when their difference is perceived by one and the same Sense as White and Black and in the Genus when their difference is not perceived but by divers Senses as White and Hot. 3 And the Likeness or Unlikeness Equality or Inequality of one Body to another is called their RELATION and the Bodies themselves Relatives or Correlatives Aristotle calls them 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 the first whereof is usually named the Antecedent and the second the Consequent and the Relation of the Antecedent to the Consequent according to Magnitude namely the Equality the Excess or Defect thereof is called the PROPORTION of the Antecedent to the Consequent so that Proportion is nothing but the Equality or Inequality of the Magnitude of the Antecedent compared to the Magnitude of the Consequent by their difference only or compared also with their difference For Example the Proportion of Three to Two consists only in this that Three exceeds Two by Unity and the Proportion of Two to Five in this that Two compared with Five is deficient of it by Three either simply or compared with the numbers different and therefore in the Proportion of Unequals the Proportion of the Lesse to the Greater is called DEFECT and that of the Greater to the Lesse EXCESS 4 Besides of Unequals some are more some lesse and some equally unequall so that there is Proportion of Proportions as well as of Magnitudes namely where two Unequals have relation to two other Unequals as when the Inequality which is between 2 and 3 is compared with the Inequality which is between 4 and 5. In which Comparison there are alwayes four Magnitudes or which is all one if there be but three the midlemost is twice numbred and if the Proportion of the first to the second be equal to the Proportion of the third to the fourth then the four are said to be Proportionals otherwise they are not Proportionals 5 The Proportion of the Antecedent to the Consequent consists in their Difference not onely simply taken but also as compared with one of the Relatives that is either in that part of the greater by which it exceeds the lesse or in the Remainder after the lesse is taken out of the greater as the Proportion of Two to Five consists in the Three by which Five exceeds Two not in Three simply onely but also as compared with Five or Two For though there be the same difference between Two Five which is between Nine and Twelve namely Three yet there is not the same Inequality and therefore the Proportion of Two to Five is not in all Relation the same with that of Nine to Twelve but onely in that which is called Arithmetical 6 But we must not so think of Relation as if it were an Accident differing from all the other Accidents of the Relative but one of them namely that by which the Comparison is made For example the likeness of one White to another White or its Unlikeness to Black is the same Accident with its Whiteness and Equality and Inequality the same Accident with the Magnitude of the thing compared though under another Name for that which is called White or Great when it is not compared with something else the same when it is compared is called Like or Unlike Equal or Unequal And from this it follows that the Causes of the Accidents which are in Relatives are the Causes also of Likeness Unlikeness Equality and Inequality namely that he that makes two Unequal Bodies makes also their Inequality and he that makes a Rule and an Action makes also if the Action be congruous to the Rule their Congruity if Incongruous their Incongruity And thus much concerning Comparison of one Body with another 7 But the same Body may at different times be Compared with it self And from hence springs a great controversie among Philosophers about the Beginning of Individuation namely in what sense it may be conceived that a Body is at one time the same at another time not the same it was formerly For example whether a Man grown old be the same Man he was whilest he was young or another Man or whether a City be in different Ages the same or another City Some place Individuity in the Unity of Matter others in the Unity of Form and one sayes it consists in the Unity of the Aggregate of all the Accidents together For Matter it is pleaded that a lump of Wax whether it be Spherical or Cubical is the same Wax because the same Matter For Form that when a Man is grown from an Infant to be an Old Man though his Matter be changed yet he is still the same Numerical Man for that Identity which cannot be attributed to the Matter ought probably to be ascribed to the Form For the Aggregate of Accidents no Instance can be made but because
the supposed hardness and therefore the other must needs be namely that the Body come neerer to A. Wherefore the Body at I has greater endeavour towards the center A when its hard side is next it then when it is averted from it But the Body in I while it is moving in the circumference of the Circle IB has sometimes one side sometimes another turned towards the center and therefore it is sometimes neerer sometimes further off from the center A. Wherefore the Body at I is not carried in the circumference of a perfect Circle which was to be demonstrated CHAP. XXII Of other Variety of Motion 1 Endeavour and Pressure how they differ 2 Two kinds of Mediums in which Bodies are moved 3 Propagation of Motion what it is 4 What motion Bodies have when they press one another 5 Fluid Bodies when they are pressed together penetrate one another 6 When one Body presseth another and doth not penetrate it the action of the pressing Body is perpendicular to the Superficies of the Body pressed 7 When a hard Body pressing another Body penetrates the same it doth not penetrate it perpendicularly unless it fall perpendicularly upon it 8 Motion sometimes opposite to that of the Movent 9 In a full Medium Motion is propagated to any distance 10 Dilatation and Contraction what they are 11 Dilatation and Contraction suppose Mutation of the smallest parts in respect of their situation 12 All Traction is Pulsion 13 Such things as being pressed or bent restore themselves have motion in their internal parts 14 Though that which carrieth another be stopped the Body carried will proceed 15 16 The effects of Percussion not to be compared with those of Waight 17 18 Motion cannot begin first in the internal parts of a Body 19 Action and Reaction proceed in the same Line 20 Habit what it is 1 I Have already in the 15th Chap. at the 2d Article defined Endeavour to be Motion through some Length though not considered as Length but as a Point Whether therefore there be resistance or no resistance the Endeavour will still be the same For simply to Endeavour is to Go. But when two Bodies having opposite Endeavours press one another then the Endeavour of either of them is that which we call Pressure and is mutual when their pressures are opposite 2. Bodies moved and also the Mediums in which they are moved are of two kinds For either they have their parts coherent in such manner as no part of the Moved Body will easily yeild to the Mouent except the whole Body yeild also and such are the things we call Hard Or else their parts while the whole remains unmoved will easily yeild to the Movent and these we call Fluid or Soft Bodies For the words Fluid Soft Tough and Hard in the same manner as Great and Little are used onely comparatively and are not different kinds but different degrees of Quality 3 To Do and to Suffer is to Move and to be moved and nothing is moved but by that which toucheth it and is also moved as has been formerly shewn And how great sover the distance be we say the first Movent moveth the last moved Body but mediately namely so as that the first moveth the second the second the third and so on till the last of all be touched When therefore one Body having opposite Endeavour to another Body moveth the same and that moveth a third and so on I call that action Propagation of Motion 4 When two fluid Bodies which are in a free and open Space press one another their parts will endeavour or be moved towards the sides not onely those parts which are there where the mutual contact is but all the other parts For in the first contact the parts which are pressed by both the endeavouring Bodies have no place either forwards or backwards in which they can be moved and therefore they are pressed out towards the sides And this expressure when the forces are equal is in a line perpendicular to the Bodies pressing But whensoever the formost parts of both the Bodies are pressed the hindermost also must be pressed at the same time for the motion of the hindermost parts cannot in an instant be stopped by the resistance of the formost parts but proceeds for some time and therefore seeing they must have some place in which they may be moved and that there is no place at all for them forwards it is necessary that they be moved into the places which are towards the sides every way And this effect followes of necessity not onely in Fluid but in Consistent and Hard Bodies though it be not alwayes manifest to sense For though from the compression of two stones we cannot with our eyes discerne any swelling outwards towards the sides as we perceive in two Bodies of wax yet we know well enough by reason that some tumor must needs be there though it be but little 5 But when the Space is enclosed and both the Bodies be fluid they will if they be pressed together penetrate one anoteer though differently according to their different endeavours For suppose a hollow Cylinder of hard matter well stopped at both ends but filled first below with some heavy fluid Body as Quicksilver and above with Water or Aire If now the bottome of the Cylinder be turned upwards the heaviest fluid Body which is now at the top having the greatest endeavour downwards and being by the hard sides of the vessel hindered from extending it selfe sidewayes must of necessity either be received by the lighter Body that it may sink through it or else it must open a passage through it selfe by which the lighter Body may ascend For of the two Bodies that whose parts are most easily separated will the first be divided which being done it is not necessary that the parts of the other suffer any separation at all And therefore when two Liquours which are enclosed in the same vessel change their places there is no need that their smallest parts should be mingled with one another for a way being opened through one of them the parts of the other need not be separated Now if a fluid Body which is not enclosed press a hard Body its endeavour will indeed be towards the internal parts of that hard Body but being excluded by the resistance of it the parts of the fluid Body will be moved every way according to the Superficies of the hard Body and that equally if the pressure be perpendicular for when all the parts of the Cause are equal the Effects will be equal also But if the pressure be not perpendicular then the angles of Incidence being unequal the expansion also will be unequal namely greater on that side where the angle is greater because that motion is most direct which proceeds by the directest Line 6 If a Body pressing another Body do not penetrate it it will nevertheless give to the part it presseth an endeavour to yeild and recede
at severall times is by Vehemence made stronger and more praedominant than the rest which deprives us of the Sense of other Phantasmes no otherwise then the Sun deprives the rest of the starres of light not by hindering their action but by obscuring and hiding them with his excesse of brightnesse 7. But the motion of the Organ by which a Phantasme is made is not commonly called Sense except the Object be present And the Phantasme remaining after the Object is removed or past by is called Fancy and in latine Imaginatio which word because all Phantasmes are not Images doth not fully answer the signification of the word Fancy in its generall acceptation Neverthelesse I may use it safely enough by understanding it for the Greek 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 IMAGINATION therefore is nothing else but Sense decaying or weakned by the absence of the Object But what may be the cause of this decay or weakning Is the Motion the weaker because the Object is taken away If it were then Phantasmes would alwayes and necessarily be less cleare in the Imagination then they are in Sense which is not true For in Dreams which are the Imaginations of those that sleep they are no less clear then in Sense it self But the reason why in men Waking the Phantasms of things past are more obscure then those of things present is this that their Organs being at the same time moved by other present Objects those Phantasmes are the lesse praedominant Whereas in Sleep the passages being shut up externall action doth not at all disturbe or hinder internall motion If this be true the next thing to be considered will be whether any cause may be found out from the supposition whereof it will follow that the passage is shut up from the externall Objects of Sense to the internall Organ I suppose therefore that by the continuall action of Objects to which a Reaction of the Organ and more esqecially of the Spirits is necessarily consequent the Organ is wearied that is its parts are no longer moved by the Spirits without some pain and consequently the Nerves being abandoned and grown slack they retire to their fountain which is the cavity either of the Brain or of the Heart by which means the action which proceeded by the Nerves is necessarily intercepted For Action upon a Patient that retires from it makes but little Impression at the first and at last when the Nerves are by little and little slackâ—ed none at all And therefore there is no more Reaction that is no more Sense till the Organ being refreshed by Rest and by a supply of new Spirits recovering strength and motion the Sentient awaketh And thus it seems to be alwayes unless some other praeternatural cause intervene as Heat in the internal parts from lassitude or from some disease stirring the Spirits and other parts of the Organ in some extraordinary manner 8 Now it is not without cause nor so casual a thing as many perhaps think it that Phantasmes in this their great variety proceed from one another and that the same Phantasmes sometimes bring into the mind other Phantasmes like themselves and at other times extreamly unlike For in the motion of any continued Body one part followes another by cohaesion and therefore whilst we turne our Eies and other Organs successively to many Objects the motion which was made by every one of them remayning the Phantasmes are renewed as often as any of those motions comes to be praedominant above the rest and they become praedominant in the same order in which at any time formerly they were generated by Sense So that when by length of time very many Phantasmes have been generated within us by Sense then allmost any thought may arise from any other thought in so much that it may seeme to be a thing indifferent and casuall which thought shall follow which But for the most part this is not so uncertain a thing to waking as to sleeping men For the thought or Phantasme of the desired End brings in all the Phantasmes that are meanes conducing to that end and that in order backewards from the last to the first and againe forwards from the beginning to the End But this supposes both Appetite and Judgement to discerne what meanes conduce to the end which is gotten by Experience and Experience is store of Phantasmes arising from the sense of very many things For 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 and Meminisse Fancy and Memory differ onely in this that Memory supposeth the time past which Fancy doth not In Memory the Phantasmes we consider are as if they were worne out with time but in our Fancy we consider them as they are which distinction is not of the things themselves but of the considerations of the Sentient For there is in Memory something like that which happens in looking upon things at a great distance in which as the small parts of the Object are not discerned by reason of their remotenesse so in Memory many accidents and places and parts of things which were formerly perceived by Sense are by length of time decayed and lost The perpetuall arising of Phantasmes both in Sense and Imagination is that which we commonly call Discourse of the Mind and is common to men with other living Creatures For he thta thinketh compareth the Phantasmes that passe that is taketh notice of their likenesse or unlikenesse to one another And as he that observes readily the likenesses of things of different natures or that are very remote from one another is said to have a good Fancy so he is said to have a good Judgement that finds out the unlikenesses or differences of things that are like one another Now this observation of differences is not perception made by a common Organ of Sense distinct from Sense or Perception properly so called but is Memory of the differences of particular Phantasmes remaining for some time as the distinction between Hot and Lucid is nothing else but the Memory both of a Heating and of an Enlightning Object 9 The Phantasmes of men that sleep are DREAMS Concerning which we are taught by experience these five things First that for the most part there is neither order nor coherence in them Secondly that we dream of nothing but what is compounded and made up of the Phantasmes of Sense past Thirdly that somtimes they proceed as in those that are drowsy from the interruption of their Phantasmes by little and little broken and altered through sleepiness and sometimes also they begin in the midst of sleep Fourthly that they are clearer then the Imaginations of waking men except such as are made by Sense itself to which they are equal in clearness Fifthly that when we dream we admire neither the places nor the looks of the things that appear to us Now from what hath been said it is not hard to shew what may be the causes of these Phaenomena For as for the first seeing all Order and Coherence proceeds from frequent
sometimes Aversion to the same thing as they think it will either be for their good or their hurt while that vicissitude of Appetites and Aversions remains in them they have that series of Thoughts which is called DELIBERATION which lasteth as long as they have it in their power to obtain that which pleaseth or to avoid that which displeaseth them Appetite therefore and Aversion are simply so called as long as they follow not Deliberation But if Deliberation have gone before then the last act of it if it be Appetite is called WILL if Aversion UNWILLINGNESSE so that the same thing is called both Will and Appetite but the consideration of them namely before and after Deliberation is divers Nor is that which is done within a Man whilest he Willeth any thing different from that which is done in other living Creatures whilest Deliberation having preceded they have Appetite Neither is the freedome of Willing or not willing greater in Man then in other living Creatures For where there is Appetite the entire cause of Appetite hath preceded and consequently the act of Appetite could not choose but follow that is hath of necessity followed as is shewn Chapt. 9th Article 5. And therefore such a Liberty as is free from Necessity is not to be found in the Will either of Men or Beasts But if by Liberty we understand the faculty or power not of Willing but of Doing what they Will then certainly that Liberty is to be allowed to both and both may equally have it whensover it is to be had Again when Appetite and Aversion do with celerity succeed one another the whole series made by them hath its name sometimes from one sometimes from the other For the same Deliberation whilest it inclines sometimes to one sometimes to the other is from Appetite called HOPE and from Aversion FEAR For where there is no Hope it is not to be called Fear but HATE and where no Fear not Hope but DESIRE To conclude all the Passions called Passions of the Minde consist of Appetite and Aversion except pure Pleasure and Pain which are a certain Fruition of good or Evil as Anger is Aversion from some imminent evil but such as is joyned with Appetite of avoiding that evil by force But because the Passions and Perturbations of the Minde are innumerable and many of them not to be discerned in any Creatures besides Men I will speak of them more at large in that Section which is concerning Man As for those Objects if there be any such which do not at all stir the Mind we are said to Contemn them And thus much of Sense in general In the next place I shall speak of Sensible Objects CHAP. XXVI Of the World and of the Starres 1 The Magnitude and Duration of the World inscrutable 2 No place in the World Empty 3 The arguments of Lucretius for Vacuum invalid 4 Other arguments for the establishing of Vacuum invalid 5 Six suppositions for the salving of the Phaenomena of Nature 6 Possible causes of the Motions Annual and Diurnal and of the apparent Direction Station and Retrogradation of the Planets 7 The supposition of Simple Motion why likely 8 The cause of the Excentricity of the annual motion of the Earth 9 The cause why the Moon hath alwayes one and the same face turned towards the Earth 10 The cause of the Tides of the Ocean 11 The cause of the Praecession of the Equinoxes 1 COnsequent to the Contemplation of Sense is the contemplation of Bodies which are the efficient causes or Objects of Sense Now every Object is either a part of the whole World or an Aggregate of parts The greatest of all Bodies or sensible Objects is the World it self which we behold when we look round about us from this point of the same which we call the Earth Concerning the World as it is one Aggregate of many parts the things that fall under inquiry are but few and those we can determine none Of the whole World we may inquire what is its Magnitude what its Duration and how many there be but nothing else For as for Place and Time that is to say Magnitude and Duration they are only our own fancies of a Body simply so called that is to say of a Body indefinitely taken as I have shewne before in the 7 chapter All other Phantasmes are of Bodies or Objects as they are distinguished from one another as Colour the Phantasme of coloured Bodies Sound of Bodies that move the Sense of Hearing c. The questions concerning the Magnitude of the World are whether it be Finite or Infinite Full or not Full Concerning its Duration whether it had a Beginning or be Eternall and concerning the number whether there be One or Many though as concerning the Number if it were of infinite Magnitude there could be no controversy at all Also if it had a beginning then by what Cause and of what Matter it was made and againe from whence that Cause and that Matter had their being will be new questions till at last we come to one or many eternall Cause or Causes And the determination of all these things belongeth to him that professeth the universal doctrine of Philosophy in case as much could be known as can be sought But the knowledge of what is Infinite can never be attained by a finite Inquirer Whatsoever we know that are Men we learn it from our Phantasmes and of Infinite whether Magnitude or Time there is no Phantasme at all so that it is impossible either for a man or any other creature to have any conception of Infinite And though a man may from some Effect proceed to the immediate Cause thereof frō that to a more remote Cause and so ascend continually by right ratiocination from Cause to Cause yet he will not be able to proceed eternally but wearied will at last give over without knowing whether it were possible for him to proceed to an end or not But whether we suppose the World to be Finite or Infinite no absurdity will follow For the same things which now appear might appear whether the Creator had pleased it should be Finite or Infinite Besides though from this that nothing can move it self it may rightly be inferred that there was some first eternal Movent yet it can never be inferred though some use to make such inference that that Movent was eternally Immoveable but rather eternally Moved For as it is true that nothing is moved by it self so it is true also that nothing is moved but by that which is already moved The questions therefore about the Magnitude and Beginning of the World are not to be determined by Philosophers but by those that are lawfully authorised to order the Worship of God For as Almighty God when he had brought his People into Judaea allowed the Priests the first fruits reserved to himself so when he had delivered up the World to the disputations of Men it was his pleasure that
the midst of the Heaven 15 The cause of Whiteness 16 The cause of Blackness 1 BEsides the Starres of which I have spoken in the last Chapt. whatsoever other Bodies there be in the World they may be all comprehended under the name of Intersidereal Bodies And these I have already supposed to be either the most fluid Aether or such Bodies whose parts have some degree of cohaesion Now these differ from one another in their several Consistencies Magnitudes Motions and Figures In Consistency I suppose some Bodies to be Harder others Softer through all the several degrees of Tenacity In Magnitude some to be Greater others Less and many unspeakably Little For we must remember that by the Understanding Quantity is divisible into divisibles perpetually And therefore if a man could do as much with his hands as he can with his Understanding he would be able to take from any given magnitude a part which should be less then any other magnitude given But the Omnipotent Creator of the World can actually from a part of any thing take another parâ— as farre as we by our Understanding can conceive the same to be divisible Wherefore there is no impossible Smalness of Bodies And what hinders but that we may think this likely For we know there are some living Creatures so small that we can scarce see their whole Bodies Yet even these have their young ones their little Veins and other Vessels and their Eyes so smal as that no Microscope can make them visible So that we cannot suppose any magnitude so little but that our very supposition is actually exceeded by Nature Besides there are now such Microscopes commonly made that the things we see with them appear a hundred thousand times bigger then they would do if we looked upon them with our bare Eyes Nor is there any doubt but that by augmenting the power of these Microscopes for it may be augmented as long as neither Matter nor the hands of Workmen are wanting every one of those hundred thousandth parts might yet appear a hundred thousand times geater then they did before Neither is the Smalness of some Bodies to be more admired then the vast Greatness of others For it belongs to the same infinite Power as well to augment infinitely as infinitely to diminish To make the great Orbe namely that whose Radius reacheth from the Earth to the Sunne but as a point in respect of the distance between the Sunne and the fixed Starres and on the contrary to make a Body so little as to be in the same proportion less then any other visible Body proceeds equally from one and the same Authour of Nature But this of the immense distance of the fixed Starres which for a long time was accounted an incredible thing is now believed by almost all the Learned Why then should not that other of the smalness of some Bodies become credible at some time or other For the Majesty of God appears no less in small things then in great and as it exceedeth humane sense in the immense greatness of the Universe so also it doth in the smalness of the parts thereof Nor are the first Elements of Compositions nor the first Beginnings of Actions nor the first Moments of Times more credible then that which is now believed of the vast distance of the fixed Starres Some things are acknowledged by mortal men to be very Great though Finite as seeing them to be such They acknowledge also that some things which they do not see may be of infinite magnitude But they are not presently nor without great study perswaded that there is any Mean between Infinite the Greatest of those things which either they see or imagine Nevertheless when after meditation contemplation many things which we wondred at before are now grown more familiar to us we then believe them and transferre our admiration from the Creatures to the Creator But how little soever some Bodies may be yet I will not suppose their quantity to be less then is requisite for the salving of the Phaenomena And in like manner I shall suppose their motion namely their Velocity and Slowness and the Variety of their Figures to be onely such as the explication of their natural causes requires And lastly I suppose that the parts of the pure Aether as if it were the First Matter have no motion at all but what they receive from Bodies which float in them and are not themselves fluid 2 Having laid these Grounds let us come to speake of Causes and in the first place let us inquire what may be the cause of the Light of the Sunne Seeing therefore the Body of the Sunne doth by its simple circular motion thrust away the ambient aethereall substance sometimes one way sometimes another so that those parts which are next the Sunne being moved by it doe propagate that motion to the next remote parts and these to the next and so on continually it must needs be that notwithstanding any distance the foremost part of the Eie will at last be pressed and by the pressure of that part the motion will be propagated to the innermost part of the Organ of Sight namely to the Heart and from the reaction of the Heart there will proceed an endeavour back by the same way ending in the endeavour outwards of the Coat of the Eie called the Retina But this endeavour outwards as has been defined in the 25 chapter is the thing which is called Light or the Phantasme of a Lucid Body For it is by reason of this Phantasme that an Object is called Lucid. Wherefore we have a possible cause of the Light of the Sunne which I undertook to find 3 The generation of the Light of the Sunne is accompanied with the generation of Heat Now every man knowes what Heat is in himselfe by feeling it when he growes Hot but what it is in other things he knowes onely by ratiocination For it is one thing to grow Hot and another thing to Heat or make Hot. And therefore though we perceive that the Fire or the Sunne Heateth yet we doe not perceive that it is it selfe Hot. That other living creatures whilest they make other things Hot are Hot themselves we inferre by reasoning from the like sense in our selves But this is not a necessary inference For though it may truly be said of living Creatures that They Heat therefore they are themselves Hot yet it cannot from hence be truly inferred that Fire Heateth therefore it is it selfe Hot no more then this Fire causeth Pain therefore it is it self in Pain Wherefore that is onely and properly called Hot which when we feel we are necessarily Hot. Now when we grow Hot we find that our Spirits and Blood and whatsoever is fluid within us is called out from the internall to the externall parts of our Bodies more or lesse according to the degree of the Heat and that our Skin swelleth He therefore that can give a possible cause
But in the mean time the hard particles which are mingled with the Aire and are agitated as I have supposed with Simple Motion wil not pass through the water of the clouds but be more straightly compressed within their cavities And this I have demonstrated at the 4th and 5th Articles of the 22th Chapter Besides seeing the Globe of the Earth floateth in the Aire which is agitated by the Sunnes Motion the parts of the Aire resisted by the Earth will spread themselves every way upon the Earths Superficies as I have shewn at the 8th Article of the 21th Chapter 5 We perceive a Body to be Hard from this that when touching it we would thrust forwards that part of the same which we touch we cannot do it otherwise then by thrusting forwards the whole Body We may indeed easily and sensibly thrust forwards any particle of the Aire or Water which we touch whilst yet the rest of its parts remain to sense unmoved But we cannot do so to any part of a stone Wherfore I define a Hard Body to be that whereof no part can be sensibly moved unless the whole be moved Whatsoever therefore is Soft or Fluid the same can never be made Hard but by such motion as makes many of the parts together stop the motion of some one part by resisting the same 6 These things premised I shall shew a possible cause why there is greater Cold neer the Poles of the Earth then further from them The motion of the Sunne between the Tropicks driving the Aire towards that part of the Earths Superficies which is perpendicularly under it makes it spread it self every way and the velocity of this expansion of the Aire grows greater and greater as the Superficies of the Earth comes to be more and more straightned that is to say as the Circles which are parallel to the Aequator come to be less and less Wherefore this expansive motion of the Aire drives before it the parts of the Aire which are in its way continually towards the Poles more and more strongly as its force comes to be more and more united that is to say as the Circles which are parallel to the Aequator are less and less that is so much the more by how much they are neerer to the Poles of the Earth In those places therefore which are neerer to the Poles there is greater Cold then in those which are more remote from them Now this expansion of the Aire upon the Superficies of the Earth from East to West doth by reason of the Sunnes perpetual accession to the places which are successively under it make it Cold at the time of the Sunnes Rising and Setting but as the Sunne comes to be continually more and more perpendicular to those cooled places so by the Heat which is generated by the supervening Simple Motion of the Sunn that Cold is again remitted and can never be great because the action by the which it was generated is not permanent Wherefore I have rendred a possible cause of Cold in those places that are neer the Poles or where the obliquity of the Sunne is great 7 How Water may be congeled by Cold may be explained in this manner Let A in the first figure represent the Sunne and B the Earth A will therefore be much greater then B. Let EF be in the plain of the Equinoctial to which let GH IK and LC be parallel Lastly let C and D be the Poles of the Earth The Aire therefore by its action in those parallels will rake the Superficies of the Earth and that with motion so much the stronger by how much the parallel Circles towards the Poles grow less and less From whence must arise a Wind which will force together the uppermost parts of the water and withal raise them a little weakning their endeavour towards the Center of the Earth And from their endeavour towards the center of the Earth joyned with the endeavour of the said Wind the uppermost parts of the water will be pressed together and coagulated that is to say the top of the water will be skinned over and hardned And so againe the Water next the top will be hardned in the same manner till at length the Ice be thick And this Ice being now compacted of little hard Bodies must also containe many particles of ayre received into it As Rivers and Seas so also in the same manner may the Clouds be frozen For when by the ascending and descending of severall Clouds at the same time the Air intercepted between them is by compression forced out it rakes by little little hardens them And though those smal drops which usually make Clouds be not yet united into greater Bodies yet the same Wind will be made by it as water is congeled into Ice so will Vapours in the same manner be congeled into Snow From the same cause it is that Ice may be made by art and that not farre from the fire For it is done by the mingling of Snow and Salt together and by burying in it a small vessell full of Water Now while the Snow and Salt which have in them a great deale of aire are melting the aire which is pressed out every way in Wind rakes the sides of the Vessel and as the Wind by its motion rakes the Vessell so the Vessell by the same motion and action congeles the Water within it We find by experience that Cold is allwayes more Remisse in places where it raynes or where the weather is cloudy things being alike in all other respects then where the aire is cleare And this agreeth very well with what I have sayd before For in cleare weather the course of the Wind which as I sayd even now rakes the Superficies of the Earth as it is free from all interruption so also it is very strong But when small drops of water are either rising or falling that Wind is repelled broken and dissipated by them and the lesse the Wind is the lesse is the Cold. We find also by experience that in deep Wells the Water freezeth not so much as it doth upon the Superficies of the Earth For the Wind by which Ice is made entring into the Earth by reason of the laxity of its parts more or lesse loseth some of its force though not much So that if the Well be not deep it will freeze whereas if it be so deep as that the Wind which causeth cold cannot reach it it will not freeze We find moreover by experience that Ice is lighter then Water The cause whereof is manifest from that which I have already shewn namely that Aire is received in and mingled with the particles of the Water whilest it is in congeling 8 We have seen one way of making things Hard namely by Congelation Another way is thus Having already supposed that innumerable Atomes some harder then others and that have several simple motions of their own are intermingled with the aethereal substance
it alone and pass on to the search of the causes of Gravity 2 Now we call those Bodies Heavy which unless they be hindred by some force are carried towards the center of the Earth and that by their own accord for ought we can by Sense perceive to the contrary Some Philosophers therefore have been of opinion that the Descent of Heavy Bodies proceeded from some internal Appetite by which when they were cast upwards they descended again as moved by themselves to such place as was agreeable to their nature Others thought they were attracted by the Earth To the former I cannot assent because I think I have already clearly enough demonstrated that there can be no beginning of motion but from an external moved Body and consequently that whatsoever hath motion or endeavour towards any place will alwayes move or endeavour towards that same place unless it be hindered by the reaction of some external Body Heavy Bodies therefore being once cast upwards cannot be cast down again but by external motion Besides seeing inanimate Bodies have no Appetite at all it is ridiculous to think that by their own innate Appetite they should to preserve themselves not understanding what preserves them forsake the place they are in and transferre themselves to another place whereas Man who hath both Appetite and understanding cannot for the preservation of his own life raise himselfe by leaping above three or four feet from the ground Lastly to attribute to created Bodies the power to move themselves what is it else then to say that there be creatures which have no dependance upon the Creator To the later who attribute the Descent of Heavy Bodies to the attraction of the Earth I assent But by what motion this is done hath not as yet been explained by any man I shall therefore in this place say somewhat of the manner and of the way by which the Earth by its action attracteth Heavy Bodies 3 That by the supposition of simple motion in the Sunne homogeneous Bodies are congregated and heterogeneous dissipated has already been demonstrated in the 5th Article of the 21 Chapter I have also supposed that there are intermingled with the pure Air certain little Bodies or as others call them Atomes which by reason of their extreme smalness are invisible and differing from one another in Consistence Figure Motion Magnitude from whence it comes to pass that some of them are congregated to the Earth others to other Planets and others are carried up and down in the spaces between And seeing those which are carried to the Earth differ from one another in Figure Motion and Magnitude they will fall upon the Earth some with greater others with less Impetus And seeing also that we compute the several degrees of Gravity no otherwise then by this their falling upon the Earth with greater or less Impetus it follows that we conclude those to be the more Heavy that have the greater Impetus and those to be less Heavy that have the less Impetus Our enquiry therefore must be by what means it may come to pass that of Bodies which descend from above to the Earth some are carried with greater others with less Impetus that is to say some are more Heavy then others We must also enquire by what means such Bodies as settle upon the Earth may by the Earth it self be forced to ascend 4 Let the Circle made upon the center C in the 2d figure be a great Circle in the Superficies of the Earth passing through the points A and B. Also let any Heavy Body as the stone A D be placed any where in the plain of the Aequator and let it be conceived to be cast up from A D perpendicularly or to be carried in any other line to E and supposed to rest there Therefore how much space soever the stone took up in A D so much space it takes up now in E. And because all place is supposed to be full the space A D will be filled by the aire which flows into it first from the neerest places of the Earth and afterwards successively from more remote places Upon the center C let a Circle be understood to be drawn through E and let the plain space which is between the Superficies of the Earth and that Circle be divided into plain Orbs equal and concentrique of which let that be the first which is contained by the two perimeters that pass through A D. Whilst therefore the aire which is in the first Orbe filleth the place A D the Orbe it self is made so much less and consequently its latitude is less then the straight line A D. Wherefore there will necessarily descend so much aire from the Orbe next abvoe In like manner for the same cause there will also be a descent of aire from the Orbe next above that and so by Succession from the Orbe in which the Stone is at rest in E. Either therefore the Stone it self or so much aire will descend And seeing aire is by the diurnal revolution of the Earth more easily thrust away then the Stone the aire which is in the Orbe that contains the Stone will be forced further upwards then the Stone But this without the admission of Vacuum cannot be unless so much aire descend to E from the place next above which being done the Stone will be thrust downwards By this means therefore the Stone now receives the beginning of its Descent that is to say of its Gravity Furthermore whatsoever is once moved will be moved continually as hath been shewn in the 19th Article of the 8th Chapter in the same way and with the same celerity except it be retarded or accelerated by some external Movent Now the aire which is the onely Body that is interposed between the Earth A and the stone above it E will have the same action in every point of the straight line E A which it hath in E. But it depressed the stone in E and therefore also it will depress it equally in every point of the straight line E A. Wherefore the stone will descend from E to A with accelerated motion The possible cause therefore of the Descent of Heavy Bodies under the Aequator is the Diurnal motion of the Earth And the same demonstration will serve if the stone be placed in the plain of any other Circle parallel to the Aequator But because this motion hath by reason of its greater slowness less force to thrust off the aire in the parallel Circles then in the Aequator and no force at all at the Poles it may well be thought for it is a certain consequent that Heavy Bodies descend with less and less velocity as they are more more remote from the Aequator that at the Poles themselves they wil either not descend at all or not descend by the Axis which whether it be true or false Experience must determine But it is hard to make the experiment both because the
to be setled any where as at H. If now the heat of the aire be augmented the water will descend below H and if the heat be diminished it will ascend above it Which though it be certainely known to be true by experience the cause neverthelesse hath not as yet been discovered In the 6 and 7 articles of the 27th chapter where I consider the cause of Cold I have shewne that fluid Bodies are made colder by the pressure of the aire that is to say by a constant Wind that presseth them For the same cause it is that the Superficies of the water is pressed at F and having no place to which it may retire from this pressure besides the cavity of the Cylinder between H and E it is therefore necessarily forced thither by the Cold and consequently it ascendeth more or lesse according as the Cold is more or lesse encreased And againe as the Heat is more intense or the Cold more remisse the same water will be depressed more or lesse by its own Gravity that is to say by the cause of Gravity above explicated 13 Also Living creatures though they be Heavy can by Leaping Swimming Flying raise themselvs to a certain degree of height But they cannot do this except they be supported by some resisting Body as the Earth the Water and the Aire For these motions have their beginning from the contraction by the helpe of the Muscles of the Body animate For to this contraction there succeedeth a distension of their whole Bodies by which distension the Earth the Water or the Aire which supporteth them is pressed and from hence by the reaction of those pressed Bodies Living Creatures acquire an endeavour upwards but such as by reason of the Gravity of their Bodies is presently lost againe By this endeavour therefore it is that Living creatures rayse themselues up a little way by Leaping but to no great purpose but by Swimming Flying they raise themselves to a greater height because before the effect of their endeavour is quite extinguished by the Gravity of their bodies they can renew the same endeavour againe That by the power of the Soule without any antecedent contraction of the Muscles or the helpe of something to support him any man can be able to raise his Body upwards is a childish conceipt For if it were true a man might raise himselfe to what height he pleased 14 The diaphanous Medium which surrounds the Eie on all fides is invisible Nor is Aire to be seen in Aire nor Water in Water nor any thing but that which is more opacous But in the confines of two diaphanous Bodies one of them may be distinguished from the other It is not therefore a thing so very ridiculous for ordinary people to think all that Space empty in which we say is Aire it being the worke of Reason to make us conceive that the Aire is any thing For by which of our Senses is it that we take notice of the Aire seeing we neither See nor Hear nor Tast nor Smell nor Feel it to be any thing When we feel Heat we do not impute it to the Air but to the Fire nor do we say the aire is Cold but we our selves are Cold and when we feel the Wind we rather think something is comming then that any thing is already come Also we do not at al feel the waight of water in water much less of air in air That we come to know that to be a Body which we call Aire it is by Reasoning but it is from one Reason onely namely because it is impossible for remote Bodies to work upon our Organs of Sense but by the help of Bodies intermediate without which we could have no sense of them till they came to be contiguous Wherefore from the Senses alone without reasoning from effects we cannot have sufficient evidence of the nature of Bodies For there is under-ground in some Mines of Coles a certain matter of a middle nature between Water and Aire which nevertheless cannot by Sense be distinguished from aire for it is as Diaphanous as the purest aire and as farre as Sense can judge equally penetrable But if we look upon the effect it is like that of water For when that matter breaks out of the Earth into one of those Pits it fils the same either totally or to some degree and if a Man or Fire be then let down into it it extinguishes them in almost as little time as water would do But for the better understanding of this Phaenomenon I shall describe the 6th figure In which let A B represent the pit of the Mine and let part thereof namely C B be supposed to be filled with that matter If now a lighted Cādle be let down into it below C it wil as suddenly be extinguished as if it were thrust into water Also if a grate filled with coles throughly kindled and burning never so brightly be let down as soon as ever it is below C the fire will begin to grow pale and shortly after losing its light be extinguished no otherwise then if it were quenched in water But if the grate be drawn up again presently whilest the coles are still very hot the fire will by little and little be kindled again and shine as before There is indeed between this matter water this considerable difference that it neither wetteth nor sticketh to such things as are put down into it as water doth which by the moisture it leaveth hindereth the kindling again of the matter once extinguished In like manner if a Man be let down below C he will presently fall into a great difficulty of breathing and immediately after into a swoun and die unless he be suddenly drawn up again They therefore that go down into these pits have this custome that as soon as ever they feel themselves sick they shake the rope by which they were let down to signifie they are not well and to the end that they may speedily be pulled up again For if a man be drawn out too late void of sense and motion they digg up a Turff and put his face and mouth into the fresh earth by which means unless he be quite dead he comes to himself again by little and little and recovers life by the breathing out as it were of that suffocating matter which he had sucked in whilest he was in the pit almost in the same manner as they that are drowned come to themselves again by vomiting up the water But this doth not happen in all Mines but in some onely and in those not alwayes but often In such Pits as are subject to it they use this remedy They dig another pit as DE close by it of equal depth and joyning them both together with one common channel EF they make a Fire in the bottom E which carries out at D the aire contained in the pit DE and this draws with it the aire contained in the channel EF which