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. II. Of Water.

I. Water is more hard to be con∣gealed, than Oil. WE daily Experience, that Water is more difficultly congealed than Oil, and that it never is frozen without there be a vehement Cold in the Air: Whereas Oil is apt to congeal in any place, where the Air is only inclining to Cold. And, on the other hand, Water is sooner turned to Vapours than Oil, if they be both exposed to the Sun, or set over a Fire of the same heat.

The Reason why Water is fluid, and doth not so easily congeal as Oil, is, because it hath smooth and slippery parts, like Eels; which tho' they lye close, and be entangled together; yet they never stick so close, but that they may be easily separated again. Whereas Oil consists of Parts which are easily entangled, and stick fast and close together: Which is the Reason why Oil is not so easily re∣solved into Vapours, as Water, the parts whereof, by the agitation of the subtil matter, are easily separable and hang but loose together.

II. Why Water will not easily mix with Oil. From hence it appears also, why Oil, or Air, cannot, without great difficulty, be mingled with Water; because their parts do more easily joyn together, than with the parts of this: For if you beat Water and Oil so long together in a Vessel, till they appear as one and the same Liquor; yet cannot they continue so long, but that the parts of Oil meeting again with one another, will cling together, and form several Drops, which being carried to the top of the Water by their Lightness, will there continue, whilst the parts of the Water, at the same time, do likewise run together into Drops, and so by their weight fall down to the bottom of the Vessel.

III. That Wa∣ter is not Cold, as Aristotle would have it. From what hath been said, may likewise be gathered, that Water is not cold of its own Nature, according to ARISTOTLE's Opinion, seeing that it admits heat, and doth not let it go, but by imparting it to the Air, which is colder than it. We find also, that when a River freezeth, the Ice begins at the Top, that is, in that part which is touch'd by the cold Air: Which would not hap∣pen so, if the Water were cold of its own Nature; for then it would begin to freez either in the midst, or at the bottom; or at least would freez as soon in the midst, as at the top; which yet is contrary to Experience.

IV. Why Wine is frozen sooner than Water. And for the same Reason it is, that Wine is not so easily congealed as Water; because in the Wine there be many subtil particles, easily moveable, and which are swiftly and readily agitated by the Celestial matter, which because of their subtilty are called Spirits. And therefore it is, that by how much stronger the Wine is, so much the harder it is to be frozen; and that the Spirit of Wine, when freed from its Phlegm, doth elude all the extreamest force of Cold. And accordingly it hath been found by Experience, that if a Vessel of some Rich Wine be exposed to the Air, in extream Cold weather the watry part of the Wine will be frozen, and the Spirits will continue liquid and fluid in the Center of it.

V. A Man under Wa∣ter, doth not feel the weight of it. The weight of Water is not felt at the bottom of a River: Which is a thing experienced by Divers, who are not prest down by the water that lies upon their Heads; but are as much at liberty for all that, as if they were in the free and open Air.

The Reason whereof i••▪ because no more of the water doth exert is gravity upon the Body, than would desoend, in case the Body did remove out of its place. For suppose we a Man placed at the bottom of the Vessel B, and lying in such a man∣ner * 1.1with his Body on the Hole A, as to hinder the water from running out of the Vessel, he will find that the whole weight of the Cylinder of water ABC doth lye upon him, the Basis whereof I suppose to be of the same bigness with the Hole A; who, if he himself should pass down through the Hole, the whole Cylinder of water would descend likewise; but if we should suppose the man placed somewhat higher at B, so as not to hinder the Eg••ess of the water at A, then would he no longer perceive any weight of the water which lies upon him between B and C; because if he should sink down towards A, yet the water would not fall down with him; but on the contrary, that part of the water which lies under him towards A, to the same bulk as his Body is, would come up into his place: Whence it appears, that the water rather carries him up∣wards, than bears him down, as may be proved by the Example and Experience of Divers. For which Reason also it is, that they cannot reach the bottom of the Sea, without some weight hung at their Feet.

VI. Things weighed, that are found to be of equal poise in the Air, do lose the same when weighed in the Water. For the same Reason it is, that Bodies which being weighed in the Air, are found to be of Equal weight, do lose the same equality when they are weighed in the water. Thus when Lead and Copper being weighed in the Air, are found of equal weight, if they he weighed under water, they lose the same: Because the Lead takes up less place in the water, than Copper of the same weight does; and therefore in water it must needs preponderate, tho' in the Air it was of equal poise with the Copper.

VII. How water comes to putrefie or corrupt. Water, if it stands still without motion for a while, or if it be kept close in a Vessel, doth putrefie and stink.

The Reason is, because tho' some small quantity of Salt and Sulphur be found in water; yet, because upon its standing still, they become loosed

from the union they had with the parts of the water, and run together, they consequently do easily evaporate, and thereby cause Putrefaction. Whereas, as long as the Water continues in motion, the particles of the Salt and Sulphur, are mixed with those of the water, and by this means be∣come entangled, and are hindred from flying away, and leaving the water destitute of that which doth preserve it from Putrefaction.

VIII. Why the Water sinks, or riseth higher in a Vessel. Water contain'd in a Glass-Vessel or Tube, with∣out filling it to the top, appears lower in the midst, than at the Sides or Edges. Whereas, on the contrary, if the said Vessel be fill'd to the very top, it will appear swell'd and higher at the top, and inclining to a Spherical figure.

The Reason is, because the Air presseth down the middle part of the water on every side, in a Vessel that is not quite full; whereas it only presseth the outsides of it more obliquely. But when the Vessel is full of water, besides that the water is more firmly closed in the Vessel, its middle parts are only drawn together by the Air that lies above them; whereas the Extream parts are comprest, as well by the Air that is above them, as by that which is on the Edge or Brim of it.

IX. What is the Cause of the Roundness we find in the Drops of Water. The Drops or Bubbles that are seen in water, are Round; but as soon as they touch others, they unite, and are confounded with them.

The Reason of their Roundness, is the equal pressure of the ambient or enclosed Air. For a Drop of water, being, as it were, pois'd on its point of Contact, is equally prest on all sides by the Circum-ambient Air. And as soon as it toucheth another Drop, because the pression in the place of Contact is thereby weakned, it presently becomes joyned with it. And therefore it is, that those hanging Drops, which are, as it were, supported every where, and surrounded by the Air that doth encompass them, are driven that way, where there is no Compression; that is, towards that part where they rest upon solid Bodies. And if you touch a hanging Drop, at the lower part of it, it immediately follows; because the Air doth not press at the point where it touches a solid Body.

X. Whether the same Roundness is not observed in the Drops of Spirit of Wine. But the Drops of Spirit of Wine are never Round; for seeing that this Spirit is very light, it consequently abounds with so many Pores, and its surface is so much interrupted, that but few parts of the Air can apply themselves to it, in order to their compressing of it into a Round figure, seeing that the most of them run through it, endea∣vouring the destruction of it. And therefore if this Liquor be poured down from on high, it doth not fall down in Drops like water, especially if it be highly rectified, but is immediately dissipated in the Air, that no sensible part of it comes to the Ground: Or, if it be pour'd on a Table, cover'd with Dust, it doth not turn into round Drops, but spreads it self every way, and mingles it self with all the Bodies it meets with.

XI. Whether Water may be made of Air. Air is sometimes condensed into water: Which we see in the production of Fountains, the Cause whereof the Ancients very probably assign'd to be, the changing of the Air into Water; which change is facilitated by the rest or stagnation of the Air in those parts, and by the coldness of the Rocks. For it is found by Experience, that Foun∣tains are most commonly generated in such places as these.

The Maintainers of this Opinion do very well to add the word, Probably, seeing there be several that utterly deny this, and prove the contrary by Experiment. A Modern Person, and great searcher into the Nature of things, took a Glass-Vessel with a long Neck, containing a Quart, and sealed it Hermetically; which Vessel, wherein was contained nothing but Air, he plac'd in a Barrel full of water, and left it there the space of 3 years, and never removed it thence all that time, save only to observe, whether any change had hapned to the Air; but he never could perceive the least alteration, or that any part of the Air was changed into Water; which according to the former Supposition ought to have hapned, because of the moist and cold water, wherewith the Air was surrounded on every side. Which proves them to have been mistaken, who supposed that that which was sufficient to turn Water into Ice, would also turn Air into Water: Since this change could not be brought about, by means of cold and moisture, in the time of 3 years. And the Reason of it is plainly this, because the particles of the Air being very subtil, are so continually agitated by the motion of the subtil matter, that they always are tost through one another, and there∣fore can never be turned into Water, no not by means of the most intense Cold.

XII. Why a Rope being sprinkled with wa∣ter becomes shorter. A Rope, or Cord, if it be sprinkled with water, so that it sink through it, becomes contracted, and is not so long as it was before.

The Reason is, because the several Threds, where∣of the Rope is composed, are as it were so many Pipes, which are blown up by the letting in of water into them, and so become shorter. Hence it is that the Strings of a Lute break in moist and wet weather, if they be wound up too high: For that the Threds of them, turning round like a Screw about other greater Cylinders, do by this means become contracted, and lose something of their length.

XIII. In what sense Water is said to be insipid. All Water, but more especially Rain-water, is insipid, and hath either no taste at all, or such as is hardly perceptible.

Tho', to speak exactly, there be no Bodies in this Universe that are altogether insipid; yet are some so called, because they are not endued with any eminent or very perceptible Taste; such as are some cold and waterish Herbs, the Raw white of an Egg, and Common water; because their par∣ticles have smooth surfaces, which do not enter the pores of the Tongue, nor can vellicate or twitch, but only glide over it. Thus Air is look'd upon to be insipid, because it swims upon our Spittle, and not mingling with it, makes no impression at all upon the Nerves. And for the same Reason it is, that fat Liquors do relish less less than others.

XIV. In Order to the filtring of any Liquor by a slip of Cloth, the Cloth must first be moist∣ned. Filtration cannot be performed, but with a piece of Cloth, that is throughly made wet with water: Or, if you will, Water will not ascend by a Label of Linnen or Woollen cloth, nor run down by that part which reaches down on the outside of the Vessel, except this part be first throughly made wet: For if the propendent part continues dry, the fil∣tration can never proceed.

The Reason is, because in filtration, the outward parts of the water, wherewith the cloath is wetted, do so insinuate themselves into the Threds of it, that they produce there a kind of thin skin, through which the inner parts of the water, which are in continual agitation, run downwards, and are carried towards that part of the Cloth which hangs down without the Vessel. Whereas, when any part of the Cloth continues dry, and unex∣tended by any Liquior, so long this Pipe cannot be compleated, which is necessary for the con∣veying of the water; and therefore it is neces∣sary that the whole Cloth be moistned. For we must not imagine, that the part of Cloth which hangs down without, becomes moistned, because the water that is contained in the Vessel is driven upwards, for this would be contrary to Nature; but the reason of it is this, because that part of the filter being dipt in the water, its Pores are thereby widened, and so prepared to admit more water, which by degrees entring more copiously into the same, doth still more widen the parts, and so continually makes way for the following Li∣quor to ascend.

XV. Why the water as∣cends in a Pipe fill'd with Sand. After the same manner as Liquors mount up by filters, so likewise doth water ascend in a Pipe full of Sand, placed perpendicularly in a Vessel full of water, and whose bottom or lower end, is stopt with such a Body through which the water can penetrate. For if we leave this Pipe thus, the time of 24 hours, we shall find the water to be mounted up in the Pipe through the Sand, a∣bout 18 inches high above the Level of the wa∣ter, that is in the Vessel.

XVI. Why the water that is at the bottom of Rivers runs more slowly than that which is at the top. Those that Swim take notice, that the water of Rivers doth not every where flow alike, and that the stream of the River runs more slowly at the bottom, than at the top.

It is not so in all Rivers, but only in such whose bottom or channel is uneven, and hath deep holes in it; for where all the parts of a Channel are level, there is no reason why the course of the River should be more slow at the bottom than at the top. Conclude we therefore, that this happens in such Rivers only when the bottom is interrupt¦ed with deep holes, where the water is detained longer, than it would be on a level, and conse∣quently doth not move so swiftly as the Sur∣face.

XVII. Why the water only runs down Hill. Hence it is evident that water always takes its course that way, where it finds a down-hill; for seeing that the upper parts of the water, do by their weight press those that are under them; and that they by reason of their fluidity, except they be kept in on the sides, do spread and slip a∣way; it must needs be that when the water is upon a hanging ground, and its lower parts prest by the upper, it must give way and run down∣wards, to avoid that pressure. For a down-hill ground, is more open than a plain or level, for seeing it is nothing else, but a range of perpendi∣culars the one shorter than the other it, cannot be otherwise, but that the water that lies upon a shelving ground, upon its being prest must slide down, towards the shorter perpendicular. So that it is manifest that no water flows upon the Earth, but what moves down-hill, by reason of the shorter perpendicular.

XVIII. Water con∣tainded in a Vessel of unequal thickness it not driven forwards by a greater bulk of wa∣ter. Let a Glass Vessel be made, with a narrow Arm, and fill'd with water: The water which is in the Vessel, will not be able to thrust the small quantity of water, which is in the Arm out of its place, nor lift it up higher, tho' it be in much greater quantity, and exceed it in weight.

This effect is to be attributed to the Heavenly matter, which is most swiftly carried round the Earth, and drives all Earthly Bodies towards the Center of their motion. For seeing that the water, which is in the Vessel, and that in the Arm of it have an equal Surface, they are consequently alike pressed downwards by the Heavenly matter; and therefore that great quantity of water which is in that large Vessel, hath no power to push the little water that is in the Arm out of its place, or to raise it higher.

XIX. Why a Needle Swims on the top of the water. The Surface of the water is more difficultly divided, than the more inward parts of it: For little Steel needles, being laid crossways on the Surface of the water swim upon it, but as soon as they have divided the top of it, do without stop sink to the bottom.

The Reason is, because tho' the parts of the water be uniformly moved, and constitute a smooth and even Surface; yet the parts of the Air, that surround the water, are agitated after a different manner, without any such uniformity in their Motion; by which means it comes to pass, that the Surfaces of Air and Water become smooth and polished; as we see that rough Bodies are polish∣ed by rubbing against each other. Now it is ap∣parent that smooth Bodies are more apt to resist, and exert a greater force in putting by other Bo∣dies. And therefore it cannot seem strange, see∣ing that the Surface of water is more difficultly divided, than its under parts, that it should sup∣port Steel needles laid upon it. Yet to this end, the Needle must be very slender, and must be laid a thwart upon the water, for otherwise the effect would not follow.

XX. The sharper the Keel of any Ship is the more water is draws. From what hath been said may be gathered, why a Ship with a sharp Keel, doth draw more water, and better cuts the waves, than that which hath a broader. For a Ship pusheth and takes up so much water, as its weight is, and all it con∣tains, that so the water may be prest equally on all sides. Now the sharper the Keel is, with so much the lesser compass it doth beat back and push against the water, and doth more easily di∣vide it, than when it is broader; for then it draws but little water, and pusheth away a greater quan∣tity of it. And therefore it is, that the Founda∣tions of the Arches of a Bridge are made sharp pointed towards the water, that it may slanting∣ly slide by without exerting its force upon them.

Notes

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  Figure 18.