a Glass of a certain Figure will make a Counter or a Shilling seem twenty though you be well assured there is but one And if you set a mark upon it you will finde the mark upon them all The Counter is certainly one of those things we call Bodies Are not the others so too A. No without doubt For looking through a Glass cannot make them really more than they are B. What then be they but fancies so many fancies of one and the same thing in several places A. 'T is manifest they are so many Idols mere Nothings B. When you have look'd upon a Star or Candle with both your eyes but one of them a little turn'd awry with your finger has not there appeared two Stars or two Candles And though you call it a deception of the sight you cannot deny but there were two Images of the Object A. 'T is true and observed by all men And the same I say of our faces seen in Looking-glasses and of all Dreams and of all Apparitions of dead mens Ghosts and wonder since 't is so manifest I never thought upon 't before for it is a very happy encounter and such as being by every body well understood would utterly destroy both Idolatry and Superstition and defeat abundance of Knaves that cheat and trouble the world with their devices B. But you must not hence conclude that whosoever tells his Dream or sometimes takes his direction from it is therefore an Idolater or Superstitious or a Cheater For God doth often admonish men by Dreams of what they ought to do yet men must be wary in this case that they trust not Dreams with the conduct of their lives further than by the Laws of their Country is allow'd For you know what God says Deut. 13. If a Prophet or a Dreamer of Dreams give thee a signe or a wonder and the signe come to pass yet if he did thee serve other Gods let him be put to death Here by serving other Gods since they had chosen God for their King we are to understand revolting from their King or disobeying of his Laws Otherwise I see no Idolatry nor Superstition in following a Dream as many of the Patriarches in the Old Testament and of the Saints in the New Testament did A. Yes Their own Dreams But when another man shall dream or say that he has dream'd and require me to follow that he must pardon me if I ask him by what Authority especially if he look I should pay him for it B. But if commanded by the Laws you live under you ought to follow it But when there proceed from one Sound divers Echoes what are those Echoes And when with fingers cross'd you touch a small Bullet and think it two and when the same Herb or Flower smells well to one and ill to another and the same at several times well and ill to your self and the like of Tastes what are those Echoes Feelings Odours and Tastes A. 'T is manifest they are all but Fancies But certainly when the Sun seems to my eye no bigger than a Dish there is behinde it somewhere somewhat else I suppose a real Sun which creates those fancies by working one way or other upon my eyes and other Organs of my Senses to cause that diversity of Fancy B. You say right and that is it I mean by the word Body which briefly I define to be any thing that hath a Being in it self without the help of Sense A. Aristotle I think meaneth by Body Substance or Subjectum wherein Colour Sound and other Fancies are as he says inherent For the word Essence has no affinity with Substance And Seneca says he understands it not And no wonder for Essence is no part of the Language of mankinde but a word devised by Philosophers out of the Copulation of two names as if a man having two Hounds could make a third if 't were need of therâ— Couples B. 'T is just fo For having said in themselves for example A Tree is a Plant and conceiving well enough what is the signification of those Names knew not what to make of the word Is that couples those Names nor daring to call it a Body they called it by a new name derived from the word est Essentia and Substantia deceived by the Idiome of their own Language For in many other Tongues and namely in the Hebrew there is no such Copulative They thought the Names of things sufficiently connected when they are placed in their natural consequence and were therefore never troubled with Essences nor other Fallacy from the Copulative Est. CAP. II. Of the Principles and Method of Natural Philosophy A. THis History of the old Philosophers has not put me out of love but out of hope of Philosophy from any of their Writings I would therefore try if I could attain any knowledge therein by my own meditation But I know neither where to begin nor which way to proceed B. Your desire you say is to know the Causes of the Effects or Phaenomena of Nature and you confess they are Fancies and consequently that they are in your self so that the Causes you seek for onely are without you and now you would know how those external Bodies work upon you to produce those Phaenomena The beginning therefore of your enquiry ought to be at What it is you call a Cause I mean an Efficient Cause For the Philosophers make four kindes of Causes whereof the Efficient is one Another they call the Formal Cause or simply the form or essence of the thing caused as when they say Four equal Angles and four equal Sides are the Cause of a Square Figure or that Heaviness is the Cause that makes heavie Bodies to descend But that 's not the Cause you seek for nor any thing but this It descends because it descends The third is the Material Cause as when they say The Walls and Roof c. of a house are the cause of a House The fourth is the Final Cause and hath place onely in Moral Philosophy A. We will think of Final Causes upon some other occasion of Formal and Material not at all I seek onely the Efficient and how it acteth from the beginning to the production of the Effect B. I say then that in the first place you are to enquire diligently into the nature of Motion For the variations of Fancies or which is the same thing of the Phaenomena of Nature have all of them one Universal Efficient Cause namely the variety of Motion For if all things in the world were absolutely at rest there could be no variety of Fancy but living Creatures would be without sense of all Objects which is little less than to be dead A. What if a Childe new taken from the Womb should with open eyes be exposed to the Azure-Sky do not you think it would have some sense of the Light but that all would seem unto him Darkness B. Truly if he had no memory of any
Plato Thales and others to fetch Philosophy into Greece But long before that time abundance of them went into Assyria and had their Towns and Lands assigned them also there and were by the Hebrews called Chaldies A. Why so B. I cannot tell but I finde in Martinius Lexicon they were called Chasdim and Chesdim and as he saith from one Chesed the son of Nachor but I finde no such man as Chesed amongst the issue of Noah in the Scripture Nor do I finde that there was any certain Country called Chaldaea though a Town where any of them inhabited were called A Town of the Chaldies Martinius saith further that the same word Chasdim did signifie also Demons A. By this reckoning I should conjecture they were called Chusdim as being a Race of Ethiopians For the Land of Chus is Aethiopia and so the name degenerated first into Chuldim and then into Chaldim so that they were such another kinde of people as we call Gypsies saving that they were admired and feared for their Knavery and the Gypsies counted Rogues B. Nay pray except Claudius Ptolomaeus Author of that great Work of Astronomy the Almegest A. I grant he was excellent both in Astronomy and Geometry and to be commended for his Almegest but then for his Judiciar Astrologie annexed to it he is again a Gypsie But the Greeks that travelled you say into Egypt what Philosophy did they carry home B. The Mathematiques and Astronomy But for that sublunary Physiques which is commonly called Natural Philosophy I have not read of any Nation that studied it earlier than the Greeks from whom it proceeded to the Romans Yet both Greeks and Romans were more addicted to Moral than to Natural Philosophy in which kinde we have their Writings but loosly and incoherently written upon no other Principles than their own Passions and Presumptions without any respect to the Laws of Common-wealth which are the ground and measure of all true Morality So that their Books tend rather to teach men to censure than to obey the Laws Which has been a great hinderance to the Peace of the Western world ever since But they that seriously applied themselves to Natural Philosophy were but few as Plato and Aristotle whose Works we have and Epicurus whose Doctrine we have in Lucretius The Writings of Philolaus and many other curious Students being by fire or negligence now lost though the Doctrine of Philolaus concerning the Motion of the Earth have been revived by Copernicus and explained and confirmed by Galileo now of late A. But methinks the Natural Philosophy of Plato and Aristotle and the rest should have been cultivated and made to flourish by their Disciples B. Whom do you mean the Successors of Plato Epicurus Aristotle and the other first Philosophers It may be some of them may have been learned and worthy men But not long after and down to the time of our Saviour and his Apostles they were for the most part a sort of needy ignorant impudent cheating fellows who by the profession of the Doctrine of those first Philosophers got their living For at that time the name of Philosophy was so much in fashion and honour amongst great persons that every rich man had a Philosopher of one Sect or another to be a Schoolmaster to his Children And these were they that faining Christianity with their disputing and readiness of talking got themselves into Christian Commons and brought so many Heresies into the Primitive Church every one retaining still a tang of what they had been us'd to teach A. But those Heresies were all condemned in the first Council of Nice B. Yes But the Arrian Heresie for a long time flourished no less than the Roman and was upheld by divers Emperours and never fully extinguished as long as there were Vandals in Christendom Besides there arose daily other Sects opposing their Philosophy to the Doctrine of the Councils concerning the Divinity of our Saviour as how many Persons he was how many Natures he had And thus it continued till the time of Charlemain when he and Pope Leo the third divided the Power of the Empire into Temporal and Spiritual A. A very unequal division B. Why Which of them think you had the greater share A. No doubt the Emperour For he onely had the Sword B. When the Swords are in the hands of men whether had you rather command the Men or the Swords A. I understand you For he that hath the hands of the Men has also the use both of their Swords and strength B. The Empire thus divided into Spiritual and Temporal the freedom of Philosophy was to the power Spiritual very dangerous And for that cause it behoved the Pope to get Schools set up not onely for Divinity but also for other Sciences especially for Natural Philosophy Which when by the power of the Emperour he had effected out of the mixture of Aristotle's Metaphysicks with the Scripture there arose a new Science called School-Divinity which has been the principal Learning of these Western parts from the time of Charlemain till of very late A. But I finde not in any of the Writings of the School-men in what manner from the causes they assigne the Effect is naturally and necessarily produced B. You must not wonder at that For you enquire not so much when you see a change of any thing what may be said to be the cause of it as how the same is generated which generation is the entire progress of Nature from the efficient cause to the Effect produced Which is always a hard Question and for the most part impossible for a man to answer to For the alterations of the things we perceive by our five Senses are made by the motion of Bodies for the most part either for distance smalness or transparence invisible A. But what need had they then to assigne any cause at all seeing they could not shew the Effect was to follow from it B. The Schools as I said were erected by the Pope and Emperour but directed by the Pope onely to answer and confute the Heresies of the Philosophers Would you have them then betray their Profession and Authority that is to say their Livelihood by confessing their ignorance Or rather uphold the same by putting for causes strange and unintelligible words which might serve well enough not onely to satisfie the people whom they relied on but also to trouble the Philosophers themselves to finde a fault in A. Seeing you say that Alteration is wrought by the Motion of Bodies pray tell me first what I am to understand by the word Body B. It is a hard Question though most men think they can easily answer it as that it is whatsoever they can see feel or take notice of by their Senses But if you will know indeed what is body we must enquire first what there is that is not Body You have seen I suppose the Effects of Glasses how they multiply and magnifie the Object of our sight as when
every way and also continually change place to fill up the places forsaken by other parts of the Air which else would be empty there being no Vacuum to retire unto So that there would be a perpetual stream of Air and in a contrary way to the Motion of the Suns Body such as is the Motion of Water by the sides of a Ship under sail A. But this Motion of the Earth from West to East is onely Circular such as is described by a Compass about a Centre and cannot therefore repel the Air as the Sun does And the Disciples of Copernicus will have it to be the Cause of the Moons monthly motion about the Earth B. And I think Copernicus himself would have said the same if his purpose had been to have shewn the Natural Causes of the Motions of the Stars But that was no part of his designe which was onely from his own observations and those of former Astronomers to compute the times of their Motions partly to foretel the Conjunctions Oppositions and other Aspects of the Planets and partly to regulate the times of the Churches Festivals But his followers Kepler and Galileo make the Earths Motion to be the Efficient Cause of the Monthly motion of the Moon about the Earth which without the like Motion to that of the Sun in LM is impossible Let us therefore for the present take it in as a necessary Hypothesis which from some Experiment that I shall produce in our following discourses may prove to be a certain truth A. But seeing A is the Centre both of the Suns Body and of the Annual Motion of the Earth How can it be as all Astronomers say it is that the Orb of the Annual Motion of the Earth should be Excentrique to the Suns Body For you know that from the Vernal Aequinox to the Autumnal there be 187 days but from the Autumnal Aequinox to the Vernal there be but 178 days What Natural Cause can you assigne for this Excentricity B. Kepler ascribes it to a Magnetique vertue viz. that one part of the Earths Superficies has a greater kindness for the Sun than the other part A. I am not satisfied with that It is Magical rather than Natural and unworthy of Kepler Tell me your own opinion of it B. I think that the Magnetical vertue he speaks of consisteth in this that the Southern Hemisphere of the Earth is for the greatest part Sea and that the greatest part of the Northern Hemisphere is dry Land But how it is possible that from thence should proceed the Excentricity the Sun being neerest to the Earth when he is in the Winter-Solstice I shall shew you when we come to speak of the Motions of Air and Water A. That 's time enough For I intend it for our next meeting In the mean time I pray you tell me what you think to be the Cause why the Equinoctial and consequently the Solstitial points are not always in one and the same point of the Ecliptique of the Fixt Stars I know they are not because the Sun does not rise and set in points diametrally opposite For if it did there would be no difference of the Seasons of the year B. The cause of that can be no other than that the Earth which is l m hath the like Motion to that which I suppose the Sun to have in L M compounded of streight and circular from West to East in a day as the Annual Motion hath in a year so that not reckoning the Excentricity it will be moved through the Ecliptiques one Revolution as Copernicus proveth about one degree Suppose then the whole Earth moved from H to I which is half the year circularly but falling from I to i in the same time about 30 minutes and as much in the other Hemisphere from H to k then draw the line i k which will be equal and parallel to H I and be the Diameter of the Aequator for the next year But it shall not cut the Diameter of the Ecliptick B Z in A which was the Equinoctial of the former year but in o 36 seconds from the first degree of Aries Suppose the same done in the Hemisphere under the Plain of the paper and so you have the double of 36 seconds that is 72 seconds or very neer for the progress of the Vernal Equinox in a year The cause why I suppose the Arch I i to be half a degree in the Ecliptique of the Earth is that Copernicus and other Astronomers and Experience agree in this that the Aequinoctial points proceed according to the order of the Signes Aries Taurus Gemini c. from West to East every 100 year one degree or very neer A. In what time do they make the whole Revolution through the Ecliptique of the Sky B. That you may reckon For we know by Experience that it hath proceeded about one degree that is 60 minutes constantly a long time in a hundred years But as 100 years to one degree so is 36000 years to 360 degrees Also as 100 years to one degree so is one year to the hundred part of one degree or 60 minutes which is 60 100 or 36 seconds for the progress of one year which must be somewhat more than a degree according to Copernicus who lib. 3. cap. 2. saith That for 400 years before Ptolomie it was one degree almost constantly Which is well enough as to the Natural Cause of the Precession of the Aequinoctial points which is the often-said compounded Motion though not an exact Astronomical Calculation A. And 't is a great signe that his Supposition is true But what is the Cause that the Obliquity of the Ecliptique that is the distance between the Aequinoctial and the Solstice is not always the same B. The necessity of the Obliquity of the Ecliptique is but a consequence to the Precession of the Aequinoctial points And therefore if from C the North-Pole you make a little Circle C u equal to 15 minutes of a degree upon the Earth and another u s equal to the same which will appear like this Figure 8 that is as Copernicus calls it a Circle twined the Pole C will be moved half the time of the Aequinoctial points in the arc C u and as much in the alternate arc u s descending to s. But in the arc s u and its alternate rising to C. The cause of the twining is the Earths Annual Motion the same way in the Ecliptique and makes the four quarters of it and makes also their revolution twice as slow as that of the Aequinoctial points And therefore the Motion of it is the same compounded Motion which Copernicus takes for his Supposition and is the cause of the Precession of the Aequinoctial points and consequently of the variation of the Obliquity adding to it or taking from it somewhere more somewhere less so as that one with another the addition is not much more nor the substraction much less than 30 minutes But as
for the Natural Efficient cause of this compounded Motion either in the Sun or the Earth or any other Natural Body it can be none but the immediate hand of the Creator A. By this it seems that the Poles of the Earth are always the same but make this 8 in the Sphere of the fixt Stars neer that which is called Cynosura B. No 'T is described on the Earth but the Annual Motion describes a Circle in the Sphere of the fixed Stars Though I think it improper to say a Sphere of the fixt Stars when 't is so unlikely that all the fixt Stars should be in the Superficies of one and the same Globe A. I do not believe they are B. Nor I since they may seem less one than another as well by their different distances as by their different magnitudes Nor is it likely that the Sun which is a fixt Star is the Efficient Cause of the Motion of those remoter Planets Mars Jupiter and Saturn seeing the whole Sphere whose Diameter is the distance between the Sun and the Earth is but a point in respect of the distance between the Sun and any other fixed Star Which I say onely to excite those that value the knowledge of the Cause of Comets to look for it in the Dominion of some other Sun than that which moveth the Earth For why may not there be some other fixed Star neerer to some Planet than is the Sun and cause such a light in it as we call a Comet A. As how B. You have seen how in high and thin Clouds above the Earth the Sun-beams piercing them have appeared like a Beard and why might not such a Beard have appeared to you like a Comet if you had lookt upon it from as high as some of the fixed Stars A. But because it is a thing impossible for me to know I will proceed in my own way of enquiry And seeing you ascribe this compounded Motion to the Sun and Earth I would grant you that the Earth whose Annual Motion is from West to East shall give the Moon her Monthly-motion from East to West But then I ask you whether the Moon have also that compounded Motion of the Earth and with it a Motion upon its own Centre as hath the Earth For seeing the Moon has no other Planet to carry about her she needs it not B. I see reason enough and some necessity that the Moon should have both those Motions For you cannot think that the Creator of the Stars when he gave them their Circular Motion did first take a Centre and then describe a Circle with a Chain or Compass as men do No he moved all the parts of a Star together and equally in the Creation And that 's the reason I give you The necessity of it comes from this Phaenomenon that the Moon doth turn one and the same face towards the Earth Which cannot be by being moved about the Earth parallelly unless also it turn about its own Centre Besides we know by experience that the Motion of the Moon doth adde not a little to the Motion of the Sea Which were impossible if it did not adde to the Stream of the Air and by consequence to that of the Water A. If you could get a piece of the true and intimate Substance of the Earth of the bigness of a Musquet-bullet do you believe that the Bullet would have the like compounded Motion to that which you attribute to the Sun Earth and Moon B. Yes truly but with less strength according to its magnitude saving that by its Gravity falling to the Earth the activity of it would be unperceived A. I will trouble you no more with the Nature of Celestial appearances But I pray you tell me by what art a man may finde what part of a Circle the Diameter of the Suns Body doth subtend in the Ecliptique Circle B. Kepler says it subtends 30 minutes which is half a degree His way to finde it is by letting in the Sun-beams into a close room through a small hole and receiving the image of it upon a plain perpendicularly For by this means he hath a Triangle whose sides and angles he can know by measure and the vertical Angle he seeks for and the substance of the arc of the Suns Body A. But I think it impossible to distinguish where the part illuminate toucheth the part not illuminate B. Another way is this Upon the Aequinoctial-day with a Watch that shews the minutes standing by you observe when the lower brim of the Suns setting first comes to the Horizon and set the Index to some minute of the Watch and observe again the upper brim when it comes to the Horizon then count the minutes and you have what you look for Other way I know none CAP. V. Of the Motions of Water and Air. A. I Have considered as you bad me this compounded Motion with great admiration First it is that which makes the difference between Continuum and Contiguum which till now I never could distinguish For Bodies that are but Contiguous with any little force are parted but by this compounded Motion because every point of the body makes an equal Line in equal time and every Line crosses all the rest one part cannot be separated from another without disturbing the Motion of all the other parts at once And is not that the Cause think you that some Bodies when they are prest or bent as soon as the force is removed return again of themselves to their former figure B. Yes sure saving that it is not of themselves that they return for we were agreed that nothing can move it self but it is the Motion of the parts which are not prest that delivers those that are And this restitution the Learned now call the Spring of a Body The Greeks called it Antitypia A. When I considered this Motion in the Sun and the Earth and Planets I fancied them as so many Bodies of the Army of the Almighty in an immense field of Air marching swiftly and commanded under God by his glorious Officer the Sun or rather forced so to keep their order in every part of every of those Bodies as never to go out from the distance in which he had set them B. But the parts of the Air and other Fluids keep not their places so A. No. You told me that this Motion is not natural in the Air but received from the Sun B. True But since we seek the Natural Causes of Sublunary Effects where shall we begin A. I would fain know what makes the Sea to ebbe and flow at certain Periods and what causeth such variety in the Tides B. Remember that the Earth turneth every day upon its own Axis from West to East and all the while it so turneth every point thereof by its compounded Motion makes other Circlings but not on the same Centre which is you know a rising in one part of the day and a falling in the other part What
may have made you hot Is Motion therefore hot No. You are to consider the Concomitants of your heat as that you are more faint or more ruddy or that you sweat or feel some Endeavour of Moisture or Spirits tending outward and when you have found the Causes of those Accidents you have found the Causes of Heat which in a living Creature and specially in a Man is many times the Motion of the parts within him such as happen in sickness anger and other passions of the minde which are not in the Sun nor in Fire A. That which I desire now to know is what Motions and of what Bodies without me are the Efficient Causes of my Heat B. I shewed you yesterday in discoursing of Rain how by this compounded Motion of the Suns Body the Air was every way at once thrust off West and East so that where it was contiguous the small parts of the water were forced to rise for the avoiding of Vacuum Think then that your hand were in the place of water so exposed to the Sun Must not the Sun work upon it as it did upon the Water Though it break not the skin yet it will give to the inner Fluids and looser parts of your hand an Endeavour to get forth which will extend the skin and in some climates fetch up the bloud and in time make the skin black The Fire also will do the same to them that often sit with their naked skins too neer it Nay one may sit so neer without touching it as it shall blister or break the skin and fetch up both spirits and bloud mixt into a putrid oyly matter sooner than in a Furnace Oyl can be extracted out of a Plant. A. But if the Water be above the Fire in a Kettle what then will it do Shall the particles of water go toward the Fire as it did toward the Sun B. No. For it cannot But the Motion of the parts of the Kettle which are caused by the Fire shall dissipate the Water into Vapour till it be all cast out A. What is that you call Fire Is it a hard or Fluid Body B. It is not any other Body but that of the shining coal which coal though extinguished with Water is still the same Body So also in a very hot Furnace the hollow spaces between the shining coals though they burn that you put into them are no other Body than Air moved A. Is it not Flame B. No. For flame is nothing but a multitude of Sparks and Sparks are but the Atomes of the Fewel dissipated by the incredible swift Motion of the Movent which makes every Spark to seem a hundred times greater than it is as appears by this That when a man swings in the Air a small stick fired at one end though the Motion cannot be very swift yet the Fire will appear to the eye to be a long streight or crooked Line Therefore a great many sparks together flying upward must needs appear unto the sight as one continued Flame Nor are the sparks striken out of a Flint any thing else but small particles of the stone which by their swift Motion are made to shine But that Fire is not a substance of it self is evident enough by this that the Sun-beams passing through a Globe of Water will burn as other fire does Which beams if they were indeed Fire would be quenched in the passage A. This is so evident that I wonder so wise men as Aristotle and his followers for so long a time could hold it for an Element and one of the primary parts of the Universe But the Natural heat of a man or other living Creature whence proceedeth it Is there any thing within their Bodies that hath this compounded Motion B. At the breaking up of a Deer I have seen it plainly in his Bowels as long as they were warm And it is called the Peristaltique Motion and in the Heart of a Beast newly taken out of his Body and this Motion is called Systole and Diastole But they are both of them this compounded Motion whereof the former causeth the food to Winde up and down through the guts and the later makes the Circulation of the Blood A. What kind of Motion is the Cause of Cold Methinks it should be contrary to that which causeth Heat B. So it is in some respect For seeing the Motion that begets Heat tendeth to the separation of the parts of the Body whereon it acteth it stands with reason that the Motion which maketh Cold should be such as sets them closer together But contrary Motions are to speak properly when upon two ends of a Line two Bodies move towards each other the Effect whereof is to make them meet But each of them as to this Question is the same A. Do you think as many Philosophers have held and now hold that Cold is nothing but a privation of Heat B. No. Have you never heard the Fable of the Satyre that dwelling with a Husbandman and seeing him blow his fingers to warm them and his Pottage to cool it was so scandalized that he ran from him saying he would no longer dwell with one that could blow both Hot and Cold with one breath Yet the Cause is evident enough For the Air which had gotten a Calefactive power from his vital parts was from his mouth and throat gently diffused on his fingers and retained still that power But to cool his Pottage he streightened the passage at his lips which extinguished the Calefactive Motion A. Do you think Wind the general Cause of Cold If that were true in the greatest Winds we should have the greatest Frosts B. I mean not any of those uncertain Winds which I said were made by the Clouds but such as a Body moved in the Air makes to and against it self For it is all one Motion of the Air whether it be carried against the Body or the Body against it Such a Wind as is constant if no other be stirring from East to West made by the Earth turning dayly upon its own Centre Which is so swift as except it be kept off by some hill to kill a man as by Experience hath been found by those who have passed over great Mountains and specially over the Andies which are opposed to the East And such is the Wind which the Earth maketh in the Air by her Annual Motion which is so swift as that by the Calculation of Astronomers to go Sixty miles in a minute of an hour And therefore this must be the Motion which makes it so cold about the Poles of the Ecliptique A. Does not the Earth make the Wind as great in one part of the Ecliptique as in another B. Yes But when the Sun is in Cancer it tempers the Cold and still less and less but least of all in the Winter-Solstice where his beams are most oblique to the Superficies of the Earth A. I thought the greatest Cold had been about the Poles of the
by its dissolution transfers its Hardness to the water within B. You are merry But supposing as I do that the Ice in the Pail is more than the water in the Vessel you will finde no absurdity in the Argument Besides the Experiment you know is common A. I confess it is probable The Greeks have the word 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 whence the Latins have their word Frigus to signifie the curling of water by the Wind and use the same also for Horrour which is the passion of one that cometh suddenly into a cold Air or is put into a sudden affright whereby he shrinks and his hair stands upright Which manifestly shews that the Motion which causeth Cold is that which pressing the Superficies of a Body sets the parts of it closer together But to proceed in my Quaeries Monsieur Des Cartes who you know hath written somewhere that the noise we hear in Thunder proceeds from breaking of the Ice in the Clouds What think you of it Can a Cloud be turned into Ice B. Why not A Cloud is but Water in the Air. A. But how For he has not told us that B. You know that 't is onely in Summer and in hot weather that it Thunders or if in Winter it is taken for a Prodigie You know also that of Clouds some are higher some lower and many in number as you cannot but have oftentimes observed with spaces between them Therefore as in all Currents of water the Water is there swiftest where it is streightned with Islands so must the Current of Air made by the Annual Motion be swiftest there where it is checkt with many Clouds through which it must as it were be strained and leave behinde it many small particles of earth always in it and in hot weather more than ordinary A. This I understand and that it may cause Ice But when the Ice is made how is it broken And why falls it not down in shivers B. The particles are inclosed in small Caverns of the Ice and their Natural Motion being the same which we have ascribed to the Globe of the Earth requires a sufficient space to move in But when it is imprisoned in a less room that that then a great part of the Ice breaks And this is the Thunder-clap The Murmur following is from the settling of the Air. The Lightening is the fancie made by the recoiling of the Air against the Eye The fall is in Rain not in Shivers because the prisons which they break are extreme narrow and the shivers being small are dissolved by the Heat But in less Heat they would fall in Drops of Hail that is to say half frozen by the shaving of the Air as they fall and be in a very little time much less than Snow or Ice dissolved A. Will not that Lightning burn B. No. But it hath often kill'd men with Cold. But this extraordinary swiftness of Lightning consisteth not in the Expansion of the Air but in a straight and direct stream from where it breaks forth which is in many places successively according to the Motion of the Cloud A. Experience tells us that I have now done with my Problems concerning the great Bodies of the world the Stars and Element of Air in which they are moved and am therein satisfied and the rather because you have answered me by the Supposition of one onely Motion and commonly known and the same with that of Copernicus whose Opinion is received by all the Learned and because you have not used any of these empty terms Sympathy Antipathy Antiperistasis c. for a natural Cause as the old Philosophers have done to save their credit For though they were many of them wise men as Plato Aristotle Seneca and others and have written excellently of Morals and Politiques yet there is very little Natural Philosophy to be gathered out of their Writings B. Their Ethiques and Politiques are pleasant reading but I finde not any argument in their discourses of Justice or Vertue drawn from the supreme Authority on whose Laws all Justice Vertue and good Politiques depend A. Concerning this Cover or as some have called it the Scurf or Scab of the Terrestrial Star I will begin with you to morrow For it is a large Subject containing Animals Vegetables Metals Stones and many other kinds of Bodies the knowledge whereof is desired by most men and of the greatest and most general profit B. And this is it in which I shall give you the least satisfaction so great is the variety of Motion and so concealed from humane senses CAP. VII Of Hard and Soft and of the Atomes that flie in the Air. A. COncerning this Cover of the Earth made up of an infinite number of parts of different natures I had much ado to finde any tolerable method of enquiry But I resolved at last to begin with the Questions concerning Hard and Soft and what kinde of Motion it is that makes them so I know that in any pulsion of Air the parts of it go innumerable and inexplicable ways but I ask only if every point of it be moved B. No. If you mean a Mathematical point you know it is impossible For nothing is movable but Body But I suppose it divisible as all other Bodies into parts divisible For no Substance can be divided into Nothings A. Why may not that Substance within our Bodies which are called Animal spirits be another kind of Body and more subtile than the common Air B. I know not why no more than you or any man else knows why it is not very Air though purer perhaps than the common Air as being strained through the blood into the Brain and Nerves But howsoever that be there is no doubt but the least parts of the common Air respectively to the whole will easilier pierce with equal Motion the Body that resisteth them than the least parts of water For it is by Motion onely that any mutation is made in any thing and all things standing as they did will appear as they did And that which changeth Soft into Hard must be such as makes the parts not easily to be moved without being moved all together which cannot be done but by some Motion compounded And we call Hard that whereof no part can be put out of order without disordering all the rest which is not easily done A. How Water and Air beaten into extreme small Bubbles is hardned into Ice you have told me already and I understand it But how a soft Homogeneous Body as Air or Water should be so hardned I cannot imagine B. There is no hard Body that hath not also some degree of Gravity and consequently being loose there must be some Efficient Cause that is some Motion when it is severed from the Earth to bring the same to it again And seeing this compounded Motion gives to the Air and Water an Endeavour from the Earth the Motion which must hinder it must be in a way contrary to the compounded