An entire body of philosophy according to the principles of the famous Renate Des Cartes in three books, (I) the institution ... (II) the history of nature ... (III) a dissertation of the want of sense and knowledge in brute animals ... / written originally in Latin by the learned Anthony Le Grand ; now carefully translated from the last corrections, alterations, and large additions of the author, never yet published ... by Richard Blome.

CHAP. XXI. Of Fire.

I. What Fire is. FIRE is a Company of Particles of the Third Element, moved with the most rapid motion imaginable. Or, it is a Lucid and Fluid Body, con∣sisting of Earthly Particles, most swiftly moved by the matter of the First Element, upon which they swim, as it were.

II. Why Fire is said to be hot and shining. Fire is said to be hot, by reason of the various agitation of its Particles, whereby they are most rapidly agitated every way. It is said to be Lucid or shining, because the subtil matter, which agi∣tates the Terrestrial Particles, is whirl'd round, whence whilst it endeavours to recede or withdraw it self, it presseth the Heavenly Globuli, in which pression Light consists.

III. The variety of Fire. Nevertheless every Fire is not Hot and Shining; for there is one sort of Fire which is only shining, as in Rotten Wood and Glow-worms; and another sort which is hot only, as in Dung, and a third sort that is both hot and shining together.

IV. What is the Cause of these va∣rious Fires. Fire is only shining when the most subtil mat∣ter of the First Element running this way and that way in the strait pores of Earthly Bodies, which resist the entrance of any other matter, doth push forwards the Heavenly Globuli: or else when the said matter is in so small a quantity, that it can only press the Coelestial Globuli, which of their own nature are sufficiently incited to Motion, with∣out being able to agitate the Terrestrial Particles. Again, the Fire will be only hot, when the subtil matter is in such abundance, that it can also agi∣tate those Earthly Particles, but yet withal is so entangled with the Earthly and Watry Particles, that it cannot explicate it self, nor push forwards the Heavenly Globuli every way, in a right line. And Lastly, Fire is both shining and hot, when it is so at liberty as both to be able to press the Hea∣venly Globuli, and most swiftly to move the Ter∣restrial Particles.

V. Violent Mo∣tion produ∣ceth Fire. Violent Motions are very proper to produce this effect, because the Earthly Particles, to which they communicate themselves, tho' they be at first en∣compast with the Second Element, yet they move fast enough to drive them away from about them∣selves, and to admit nothing but the First Element, which much augmenting their agitation, doth dispose them soon to separate themselves from one another, and to take upon them the form of a Flame.

VI. Fire is kindled by driving out the Globuli from the Intervals of the Ter∣restrial Particles. In order therefore to the kindling of Fire, that is, to the gathering such store of the matter of the First Element, as may both shine and burn, it is necessary that the Globuli be driven out of the Inter∣vals of some Terrestrial Particles, which being after∣wards separated from each other, and only swiming in the matter of the First Element, may be snatched away with its most swift motion, and driven every way. That this is so, we shall easily conceive, if we consider that the matter of the First Element doth in swiftness much exceed that of the Second Element, and that those little Bodies which swim amongst the particles of these 2 Elements, can only be carried along by the motion of the Second Element, for that its Globuli do break the force of the First Element, and resist its motion: whereas on the contrary, whilst those Earthly Bodies are surround∣ed with the matter of the First Element, they must necessarily comply with its agitation, in like manner as we see that a piece of wood is carried away by the swiftness of the stream wherein it swims.

VII. Whence it is that the Brightness of a Flame is greater in a dark than in a light Place▪ Thus we find that the Brightness of a Flame is greater, and more conspicuous in a dark Place, than in one enlightned by the Sun; because in a place so illustrated, many Globuli of the Second Element from the Sun, are sent into the Flame, which lessen the agitation of the matter of the First Element, and consequently also the violence of the Fire. Whence also it is that when our Optick Nerve is strongly affected by the Fulgid Light of the Sun, the light of a Candle, compa∣red with that of the Sun, seems to be none at all▪ as being scarcely discernable by our Eyes.

VIII. Why Fire is hot and shining. From what hath been said, we may gather the chief Qualities of Fire: for seeing that its particles are solid, and most swiftly moved, they cannot but produce heat, which, as shall be said in the follow∣ing Chapter, is nothing else save the actual vari∣ous motion of the little parts of the Body, affecting

the sense of feeling. And so also if together with this we call to mind, what before hath been said concerning Light, viz. that it consists in an endea∣vour of receding from the Center, or in the pres∣sure of the Heavenly Globuli. For seeing that the subtil matter, that constitutes Fire, is constantly whirled round, and endeavours to recede thence, it cannot but procreate the sense of Light, and make the Fire Bright and Shining.

IX. Of the se∣veral ways whereby Fire may be kindled. Fire may be kindled several ways: First out of Flints, for they being of a hard substance, if other stiff Bodies dash against them, by this means the Globuli of the Second Element, because of the nar∣rowness of the interjected space, are forced to march off, leaving only behind them the matter of the First Element, and so the Earthly Particles which swim upon it, and follow its motion produce Fire and are turned to Sparks. Which may be the Cause why we find that in Subterraneous Places Fire is often kindled. For since there is always in those places a viscous slimy matter, and many ex∣halations are sublimed there by the Suns heat, it may so happen that one Flint dashing against ano∣ther, may send forth sparks, by which the exhala∣tions that cleave to the kindled viscous or sulphure∣ous matter, may communicate a flame to the Bo∣dies that are nearest to them. Now that there are such fat and sulphurous Flames in the Bowels of the Earth, is well known to the Miners, and Reason evinceth the same; for seeing that there is a Fire in the Bowels of the Earth, there must be Fumes arising from it; seeing also that there are sulphurous hot Bathes, and veins of Jews Lime, and other oily matter boyling in the hidden Channels of the Earth, we may easily judge that from these also a continual Smoak or Fume must proceed by way of exhalation. And it seems probable, that the first kindling of those Fires which burn in Mount Aet∣na in Sicily, and Vesuvius in Campania, hapned after this manner.

X. How Fire is kindled by a Burn∣ing Glass. There is also another way of kindling Fire, viz. when the Beams of the Sun are concentred in a concave Glass, for by this means the Globuli act∣ing with their joint forces, do excite a various and vehement excitation of the Terrestrial Particles, whence proceeds a Flame, the Heavenly Globuli being beaten back, by the swift agitation of the Terrestrial Particles, so as that the Particles of the most subtil matter can freely flow together and continue this agitation.

XI. Sharp Spi∣rits can also kindle a fire. A Fire also may be kindled by sharp Spirits, as appears in Hay, which if it be laid up before it be sufficiently dry, it becomes hot by degrees, and at last breaks forth into a Flame, because the Spirits of Herbs that are shut up in it, have not so free an egress, as when they were Green, and before they began to be dried; and therefore being no longer able to enter into the same passages, with the Globuli of the Second Element, they become surrounded only by the matter of the First Ele∣ment, which putting them into a most swift motion, makes a Flame to appear. But this never happens in Wood, tho' it be struck never so much, because its substance is not stiff enough, that by a concus∣sion of another hard Body, the Globuli of the Se∣cond Element should be driven away, because the part that is struck bends towards another, before that the Second begins to bend towards the Third, and that again towards those that are next to it, by which means its force of flying back is lost.

XII. How Fire is Nourish•• or Fed. But forasmuch as Flame is perpetually turn'd to Smoak, and is no more the same than a River, which is continually supplied by an access of new waters, it is of absolute necessity that it have some Food or Fewel whereby it may be preserved and maintained. And this is no other but those Ter∣restrial Parts, which being agitated by the matter of the First Element, have a power to drive away the Air or any other Body, that might extinguish it. It is also requisit that these particles be very thin, that they may be able to supply the room of the vanishing Smoak: for the thicker particles are easily surrounded by the Globuli of the Second Element, and possessing themselves of the places which the particles of the First Element have left, do much break the force of the Fire, and choak its Flame.

XIII. Oily and Sulphurous Bodies are a proper fewel to preserve Fire. For which reason also all Oily, Sulphurous and Bituminous Bodies are of all others most conducive to maintain and preserve Fire; for that by reason of the contexture of their Branch-like Parts, and their fit Thickness, they are most fit and disposed to be agi∣tated by the particles of the First Element, and being thereby driven out of their places, to com∣municate their motion to other Bodies with such force as that they drive away the particles of the Second Element, which otherwise would extinguish the Fire into which they strive to enter on every side.

XIV. How Flame is produced. These things premis'd, it will be easie to con∣ceive, that Flame is nothing else but a Fire wholly at liberty, that is, a Fire whose parts are so agitated, that they entirely separate themselves from each other, and do only swim in the matter of the First Element. It will be likewise readily conceived how a Flame is produc'd, by viewing the Candle AB, and reflecting that there be many parts of * 1.1Wax that move very swiftly throughout the whole space CDE, where they constitute a Flame, be∣cause they swim alone in the matter of the First Element. We must also consider, that the parts of Wax that constitute the Flame do continually strive to mount still higher, for that by reason of their great agitation they are more light than the Air, that surrounds them, which having been forced to descend continually, endeavours to return to its place again, and to which indeed it would return, if the new particles of Wax that come forth from the Wick, and which begin to follow the Course of the First Element, did not hinder it; which is confirmed by experience, which shews us that as soon as the particles of Wax cease to proceed thence, or tho' they do, yet have not force enough, the Flame ceaseth in the space CDE, and the Air possesseth it self of its place.

XV. Why the Flame always mounts up∣wards, and ends in a point. It is peculiar to Flame to mount upwards, and to end in a sharp point; the reason whereof is, be∣cause the Flame, by reason of the great abundance of the matter of the First Element that is in it, being lighter than the Air that surrounds it, must of necessity tend upwards: and because the middle parts of the Flame GDE, are more strongly agi∣tated by means of their greater solidity, than those which are about the utmost parts CC, whose mo∣tion is much diminisht by the neighbouring Air, this makes the Flame to end in a point, and its Smoak to break forth chiefly at the top H, where

the Terrestrial particles begin to lose their agita∣tion. As for Example, When the Smoak ascends towards H, it makes the Air to descend by I and K, towards B, where razing the Wick, it pushes the particles of Wax towards the flame, which serve to nourish it: Which Circular motion of the Air towards the flame, Experience shews us, in that when a Chamber is close shut, save only some little Hole or Chink, and a Fire be kindled in it, a Wind is perceived to enter in by the said Chink; and which is so much the stronger, by how much the Fire is greater.

XVI. The force of Fire upon Earth∣ly Bodies. Fire is extreamly active, and exerts its Force upon the hardest Bodies; for its Particles, as so many sharp Needles penetrate their Pores, and driving out the par∣ticles therein contained, they divide its parts, and turn them into their own Matter; and in case the particles of the Bodies, the Fire acts upon, are easily separable, then they melt. For to be melted, or in a liquid form, imports nothing else, but that the Body in that state consists of Particles that are divided from each other, and in some agitation. As on the other hand, Bodies are dried, when by approaching to the fire, their thin and slippery Particles are exhaled, the more thick Parts being left, which being thereby more closely joyn'd together, con∣stitute hard Bodies.

XVII. The Venti∣lation of the Air is necessary, to the preser∣vation of Fire. The Ventilation of the Air is necessary to Fire; because the Air being push'd upwards by the mounting flame, cannot enter into another place, which the Fire, by consuming its Fewel, leaves open for it; and whilst it thus succeeds, it like a Fan or Bellows, drives the fire into the more in∣ward parts of the fewel, and dissipating those that are more Heavy, doth thus by blowing preserve the fire: For where this is not, and the Air is hindred from supplying the said place, the flame not being able to give way, becomes choak'd by the more heavy and gross Fumes.

XVIII. Fire is ex∣tinguish'd by any Li∣quor poured upon it. Fire is put out, when any liquor or moisture is poured upon it in a greater quantity, than can be put into motion by the force of the fired Par∣ticles; which is the Cause why a little Water in∣creaseth the Fire, whereas a great deal of it doth put it out.

XIX. Why the Air must have free access into a Chamber, that the Fire may not fill it with Smoak. Hence it is, that when a Fire is kindled in a Chamber, if the Air hath no free access to it, the whole Chamber becomes presently fill'd with Smoak. Because the Air drives away from it great store of Air, together with the Particles, of combustible Bodies: For it is these that being mix'd with the Air, constitute the Smoak, as the more solid Parts of those Bodies are turn'd to Ashes. And since it is repugnant that there should be any Vacuum in Nature, it is necessary that so much Air enter the Chamber, as there is Smoak going out: For except this be, the whole Chamber will be fill'd with Smoak.

Notes

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  Figure 59.