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.

(Book 4)

[illustration]

Book. 2. Part. 4. Chap. ••

G. Freman Inv.

I. Kip S••

(Book 4)

The Fourth Part OF THE HISTORY OF NATURE. OF EARTH, WATER, FIRE and AIR. (Book 4)

CHAP. I. Of the Globe of Earth.

I. Why the Earth, as containing the Water, is called a Terraque∣ous Globe. THE Earth, forasmuch as it con∣tains in its Cavities the Waters, and together with them constitutes one Globe, is called the Terraque∣ous Globe.

For when we take a Voyage by Sea, sailing in the Atlantick Ocean, and passing through the Magellan Straits, towards the South Sea, and so on to the East and Aethiopick Seas, we find that all these Seas are encompast with Shores. And in like manner, when we travel by Land, we shall find the Land bounded, on one side with the Atlantick and Aethiopick Seas, and on the other with the South Seas; and again, this way with the Eastern and Arabian; and that way with the Tartarian, Atlantick and Aethiopick Seas.

II. The Earth is but a Point, com∣pared with the vast extent of Heaven. Tho' the Earth be of that vast extent, that its compass is of about 7000 French Leagues; or ac∣cording to the later investigation of WILLO∣BRORDUS SNELLIUS, of 24624 Miles: Yet if we will believe Astronomers, it is no more than a Point, compared with the vast Cir∣cumference of Heaven.

Neither is this Assertion of theirs without ground: For so great is the distance betwixt the Earth and the fixt Stars, that it cannot be cer∣tainly determined, as exceeding all Calculation; and can scarcely be apprehended by our Imagina∣tion. The distance of the Planets may be discern∣ed by their Parallax, or that variation of Aspect they afford to several Spectators in distant places; but the Fixt Stars are at so prodigious a distance, that no Parallax is to be found in the beholding of them, and the Semidiameter of the Earth, with relation to them, is as nothing. So that if some one of us should be supposed to continue in the place of the Earth, whilst it was carried up to∣wards Heaven; there is no question, but at its first rising, it would shew like a vast Globe; but as it mounted higher, would still decrease to our sight; till being got up as high as Jupiter, it would appear no bigger than one of the lesser Stars; and rising higher towards the Fixt Stars, would become invisible to us. And therefore the Earth which contains so many Seas, so many King∣doms, so many Islands, yet is no more than a point, with respect to the Heavens. Yea, when compared to our Vortex, which hath the Sun in its Center, we shall find it so inconsiderable, that they who make Sundials, suppose the top of the Pins of them to be placed in the center of the Earth, whence they cast their shadows upon the surface of it; as if the difference were so small, that it comes to the same thing, whether they cast their shadows from the Center, or the surface of it, the distance being so very inconsiderable in comparison to the Suns distance.

III. How vain Men are, that make such pother and fight∣ing about a silly point of Earth. This may give us an estimate of the folly of Men, who for one point of Earth, wage so many Bloody Wars, yea, for the 1000th or 100000th part of it. This forsooth, as PLINY saith, is the matter of our Glory. Here we enjoy our Honour; here we exercise our Dominion; here we have our Riches and Possessions; here mankind continually Bustles, Toyls and Turmoyls it self; here we wage Wars, and soak the Earth with one anothers Blood; and our Swords destroy our own kind. But not to speak now of the publick feuds, and fury of whole Nations against each other: Here it is that we endeavour to lay one clod of Earth to anotherl; and after having purchased all the poor pittances of our Neighbours about us, what a brave purchase have we made after all? And what great Reason have we to boast in being Posses∣sors of not so much as the thousand thousandth part of a point? But this is to sing a Song to a Deaf∣man; return we therefore to our Earth.

IV. How the Earth hangs pois'd in the Air, without any thing to support it. The Earth hangs in the midst of Heaven, without any Pillars to uphold it; and, as if it were immoveable, doth ever keep the same distance from the Heavenly Orbs.

This happens to the Earth, ••ot 〈…〉〈…〉 Center of the Universe, as it is comm••nly su••∣posed, and that all the Celestial Orbs, are rolled about its Circumference: For should we grant this to be, yet would the difficulty still remain, why the Earth▪ d••es not re••l from its pl••ce why it doth not e••ther mount upwards, o•• fa•• down. For if it be Heavy by Nature, how comes it to pass that it doth not rush downwards? If it be Light, why does it not fly upwards? Conclude we therefore, that the Earth doth hang pois'd in the mi••st of the A••r, by means o•• the subtil matter, which cont••••u••lly whirls ro••nd 〈◊〉〈◊〉 and p••••reeth all the por••s o•• it. For see••••g ••hat the Heavenly matter, which on all sides surrounds the Earth, is whirl'd about it with one and the same degree of Swiftness, which far exceeds that where∣with 〈◊〉〈◊〉 Eart•• ••s moved▪ it cann••t but hind•••• 〈◊〉〈◊〉 from fa••••ing, or mounting highe••. For as ••ir••s are upheld by the Air from falling; so the Earth and the Moon, wh••ch circ••••ate in th•• same Vortex, are supported by the same Ma••ter that ca••••ies them along, and hindred from Reeling any way from their Centers.

V. Why the Eart•••• by its weight, doth not come nearer to the Sun. The Earth, notwithstanding its weight, yet is not driven to the Circumference of the Sun's Vortex; but being kept within its bounds by the Heavenly Globuli that surround it, continues at a certain distance, viz. in the midst, between Mars and Mercury, without passing any fur∣ther.

The Reason is, because the Planets, amongst which the Earth is, by reason of their different degrees of solidity, are more or less removed from the Center of their Vortex: So that Saturn, who is at the greatest distance from the Sun, is more solid than all the rest. And the Earth, tho' it seem to be a close and compact Body, yet is not of that solidity, as to sway it more towards the Circum∣ference of its Vortex; forasmuch as Mars, who is much less than the Earth, yet is also more solid, by reason of the closer entanglement of its parts. For tho' the Earth, as to its surface, be very com∣pact and solid, yet with respect to its bulk, it may well be accounted light; because the surface of it is not above 2 or 3 Mile in thickness, which is very inconsiderable, if compared to those vast Cavities it hides within its Bowels. And there∣fore as little Ships, such as have no great force, are easily kept in the River, and carried by its motion: So likewise the Earth, being fallen into the Vortex of the Sun, always keeps the same place, in which, by reason of its solidity it is ranged, and cannot be pusht any further towards the Circumference of the Sun's Vortex.

VI. The Mag∣netical virtue of the Earth, doth but weakly affect Iron. The Earth communicates a Magnetick force to Iron; but the same is so weak, that it easily loseth it, and admits the contrary. Thus when we turn the End of a Bar of Iron, as yet not endued with any Magnetick virtue towards the Earth, immediately in that End which is inclin'd towards the Ground, it will obtain the force of the Sou∣thern Pole in these Northern parts, which in a moment it will lose again, and obtain the con∣trary; if that End which was towards the Earth be turned upwards, and the other End inclined downwards.

The Reason whereof is the weakness of the Magnetick ••or•••• that is in the Earth: For seeing th•••• the str••••t•• Part••••les, which proceed from out of the Earth, do retur•• ••hi••••er again through the inner Crust o•• its upper Region, whence the Me∣tals are dug up, it so happens that very few, or none of them return through our Air; those only ••••cepted, who do not find▪ a Passage in the said i••••er Crust o•••••• for them. Hence it i•• th•••• Load∣••••••nes, that h••v•• fit pores f•••• the reception of the said particles, have also a greater force to attract Iron; because the striate Particles meet with pores in the Load-stone, which are ranged in like man∣ner, as ••••e those of the in••er Crust of the Earth: Where••••, when they p••••s through the Air▪ or throug•• other Bodies of ••he outward Crust 〈◊〉〈◊〉 the Earth, where they find no such pores, they move wi••h more difficulty, and consequently also fewer of them come to us.

VII. They who Travel from North to South, find the Northern parts to be withdrawn from their sights. Pe••son•• that Travel from North to South, ••ind that the Northern parts of Heaven sink lower and lower, and by degrees withdraw from their sight; but they who pass from So••••h to North, do find the Nor••••ern parts of Heaven to be ••••••sed higher; so that after having Trav••lled 73 Italian miles in length, or 24 common French Leagues, the Northern Pole will be raised a Degree higher.

This Experiment proves the Earth to be Round; for if the Earth were plain, no such Change could be perceived. For tho' we should suppose a Man to be plac'd directly under the P••l••, yet would there be no change in the elev••••ion or height of the Pole; for if he should wi••hdraw from it in a Right Line, the depression wi•••• not be equal, nor after he hath Travelled onwards 73 Miles, would he find one Degree left behind, but the withdrawing will become still less and less, because of the continual decreasing of the Angle: So as that at last 73 Miles would scarcely make a depression of 1 minute of a Degree: Which is contrary to daily Experience.

VIII. The Moun∣tains do not hinder the Round∣ness of the Earth. The Roundness of the Earth is not hindred by those high Mountains that are found on the sur∣face of it, many of which rise much higher than the Clouds, as Olympus, Athus, and the Peak of Teneriff. Because the Roundness that is attributed to the Earth is not Mathematical, as if the Lines drawn from the Center to its Circumference were all perfectly Equal; but only Physical, that is, such a Roundness, as is suitable and convenient for the Universe; forasmuch as these Inequalites are of so great moment, that they do not come into any consideration, when compar'd with the vast ampli∣tude of the Body. For seeing that the Semidiameter of the Earth▪ is of 860 miles, the proportion of the greatest height of the Mountains, to the Semi∣diameter of the Earth, will be as one 1 to 860. And forasmuch as there be but very few Mountains that are perpendicularly so high, and that the most of them are scarcely one Quarter of a Mile in Height, it is evident that they can no more spoil the Roundness of the Earth, than some small Un∣evennesses in the Round Balls made by Artificers, do hinder their being Round. For indeed, there is not a Body to be found in the whole Universe that is perfectly and absolutely Round, that is, which hath an exact Geometrical Roundity.

IX. The Varia∣tion of the Altitude of the Pole, proves the Roundness of the Earth. This Physical Roundness of the Earth may be demonstrated by the following Experiment: When a Man travels North or South, he will find the Altitude or Elevation of the Pole to vary conti∣nually, whether he go a Plain-way, or Up-hill and Down-hill: So that if being at the Foot of a Mountain, and having observed the Elevation of the Pole, he Travel the whole day towards the South, he will not perceive the Elevation of the Pole to be increased, but rather decreased, by that time he comes to the top of the said Mountain. Neither will he in like manner find the same Alti∣tude decreased, but diminished, if having taken the Elevation of the Pole at the top of the Mountain, he goes down again to the bottom of it. Which is an evident Proof, that the Devexity or bending downwards of the Earth, is every where percep∣tible, and that a perpendicular falling upon any different Points, whether of Acclivity or Declivity, do all tend downwards by different Lines, that will meet at last in the Center.

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.

CHAP. III. Of the wonderful Properties of some sorts of Waters.

I. Of the cause of hot Waters or Baths. SOme Waters are hot when they break out of the Ground; yea there are some Springs that are so hot, as to boil an Egg hard that is put into them.

Some derive this heat that is found in hot Baths from Subterraneous Fires, which lye hid

in the Bowels of the Earth, and are diffused up and down through it by certain Channels, which as the water passeth through, it becomes heated. But this doth not seem agreeable to Reason; for whence are these Subterraneous Fires fed and maintained, where is their Fewel, or how can the same be kindled into a flame under ground? Or how comes it to pass that these Fires are not choaked by the smoak that proceeds from them? Or why do not they dilate themselves, and break∣ing out at the Surface devour all before them? It seems therefore more probable, that this heat of some waters is the effect of a mixture of Li∣quors, proper to produce that quality; as we find that water poured upon quick Lime grows hot; and the same effect ariseth from the mixture of Oyl of Tartar, with Oyl of Vitriol; and Butter of Antimony, with Spirit of Niter: Which tho' singly they be cold Liquors, yet when put toge∣ther, produce a very intense heat; for if Oyl of Tartar be poured into Aquafortis wherein Iron is dissolved, it will not only work and boil, but break forth into a Flame.

Conclude we therefore, that the heat of Baths proceeds from a mixture of Jews Lime and Brim∣stone, which being united together produce heat by effervescence.

II. The heat of Baths, doth not proceed from subter∣raneous Fires. That this is so, may be evidently proved from hence, that the water of hot Baths being set upon the Fire, is as long a boiling as any other cold water: Neither doth it scortch and burn the Tongue as common water doth, which hath ac∣quired a like degree of heat from our Culinary Fire; which shews that the Subject of this heat is a thin Vapour, which doth not so much pene∣trate the parts of the Tongue and Mouth. It is found likewise that this water, doth not boil and make tender, soft and juicy Herbs that are put into it, such as Sorrel, &c. as soon as common water, that hath the same degree of heat. The reason whereof seems to be, because the Volatile Sulphurs, that produce the heat in these waters, do so insinuate themselves into the Pores of the Mouth, or of the Leaves of Sorrel, that they hinder the water from entring into them; or be∣cause the heat of these waters doth wholly con∣sist in these Sulphurs, the parts whereof are so Subtile, that they cannot exert their force, neither upon the Mouth, nor upon the Leaves of Sorrel; for the very same reason that the flame of Spirit of Wine, will not burn a Handkerchief that hath been dipt in it.

III. Corrosive Spirits do dissolve Metals, and rather act upon hard than soft Bodies. Corrosive Spirits, or Stygian waters, as the Chymists call them, do penetrate the hardest of Metals, and in a short time do dissolve them; but act little or nothing at all upon Wax which is soft, but leave it in a manner untoucht. The said waters do also more easily dissolve Iron and Steel, than Lead, which is softer than they, and more easily divisible.

The reason is, because these Corrosive Spirits do not meddle with those Bodies that give way to them, but crumble them to pieces that oppose and resist their entrance. Which will be easily apprehended by those who know that all Bodies, do not consist of the same parts, nor have their parts joyned in one and the same manner, but suitable to the variety of their Bulk and Figures. For as a heap of Earthen Vessels, may with a Stick be broken into a Thousand pieces, whereas Wool being struck with the same Stick and force, doth admit no change at all; and as Wool may be easily cut with the edge of Knives and Scissars, whereas Earthen Vessels cannot; so we may easily understand▪ how some Bodies are easily dissolved by Corrosive Spirits, whereas others are scarcely toucht by them.

IV. A Fountain of Epirus extinguish∣eth flaming Torches, and kindles those which are extin∣guisht▪ Historians tell us of a River in Epirus, pro∣ducing contrary effects. In DODONA, saith PLINY, Is a Fountain dedicated to Jupiter, which tho' it be cold and doth extinguish the lighted Torches that are put into it, yet doth it kindle those which are extinguisht when approacht to it.

This seems at first sight impossible, that in∣flammation should proceed from a cold Body as the water is: Yet for the clearing of this difficulty we may say, that the water of this Fountain be∣ing cold, does extinguish a flaming Torch that is dipt into it, this being the property of water to quench and choak Fire, and so put a stop to the motion of its agitated parts; but the rekind∣ling of extinguisht Torches, cannot be attributed to the water, but to the Bituminous and Sulphu∣rous▪ exhalations, that rise up from the water. For it is probable, that this Fountain did send forth Vapours mixt of Jews-Lime, Brimstone and Nitre, which rising up through the Fountain as through a Chimny, became inflammable in the open Air, especially when a newly extinguisht Torch was approacht to them.

V. The cause of the In∣terruption of the flow∣ing of the Collismar∣tian Foun∣tain. GASSENDUS upon occasion of a Foun∣tain mentioned by PLINY, which Flows and Ebbs thrice a day, mentions the Collismartian Fountain, which Ebbs and Flows 8 times in an hour; for the water being ready to break forth, discovers it self by a soft purling noise, and for about half a minutes time swells and encreaseth, and the 6 following minutes decreaseth again; and when the decrease is ceased, the water con∣tinues in the same state for a little while, and then begins to flow again. But the intervals between one Eruption and another, are not equal, being sometimes more, and at other times less; tho' it very seldom happens, but that in one hour 8 flow∣ings or Eruptions, and as many Cessations or Eb∣bings may be perceived in an hour.

It is certainly a difficult matter to render a satisfactory reason of this interrupted flowing of the water; neither will the instance of the Foun∣tain in Epirus, be of any great help to us towards the solving of it. For whereas the same abounds with water in the day time, which fails and ceas∣eth in the night, this may be attributed to the heat of the Sun, whereby Fountains in Summer∣time are often dried up, and overflow in the Win∣ter. But this cant be applied to the Collismartian Fountain, which observes its interrupted Ebbings and Flowings in the night, as well as in the day time. However, if I may speak my conjecture concerning so abstruse a Riddle in Nature, I am apt to believe, that within the Hill whence this Spring breaks forth, there is some hollow, or pit, which a Rivulet continually fills up: As likewise a passage through which some subterranean steam, or breeze continually blows, and keeps back the water, sending it back to the place opposite to that from whence it came; where it then swells

and encreaseth, till being overcome by its own weight, it overbears the force of the Wind, and so runs down, until the hollow or pit be almost ex∣hausted and remain dry. And after this the Wind having recovered its free passage again, doth as before withold the waters that would run out, and continually drives it back, until by force of the water that breaks in, it be driven away again, and give way to it.

VI. Another like River. A like Fountain to this is mentioned by F. MAIGNAM TOLOSAS in his Horary Per∣spective, which in Summer time doth every hour flow from a vast, and most deep hollow, and for a quarter of an hour encreaseth bydegrees, with a very great noise; and the next quarter becomes a great River; the following quarter it sinks again, and the last quarter, lies still, and is in a manner quite dry'd up.

VII. What is the cause of poisonous or deadly Fountains. Some Fountains are Poisonous and deadly, as was that famous one of Terracina, which was called Neptunes, in the Country of the Volsci, which was the death of all those that drunk of it, and therefore was stopt up with Stones, by the Inhabitants.

This may be occasioned when the waters of such Springs run through Arsenical, Mercurial or Antimonial Mines. For as the Fumes of Arsenick do kill living Creatures, so waters impregnated with the said steam, produce the same effect. Of this kind is the Lake Asphaltites, because of the Arsenical Jews-Lime it abounds with; and many other Fountains that are found in the Countries about the Alps; but as soon as they are discover∣ed they are filled up and stopt with Stones, which is the reason why so few of these deadly Springs are known.

VIII. Whether it be true that the Fountain of Jupi∣ter Ammon was cold and hot by turns. In the Povince of Cyrene, as Historians tell us, was a Fountain of the Sun, which was hot at Midnight, and afterwards growing luke warm by degrees, was cold at the breaking of day; and as the Sun rose higher, grew still more cold, so that at Noon it was cold to extremity; and from that time began by little and litle to grow luke warm again, till at the beginning of night it was hot, and so grew hotter and hotter till Midnight.

Some Philosophers have endeavoured to give a reason of this change, by asserting that there are some Seeds of heat in water, which the Earth, when chill'd and contracted with the coldness of the night sends forth, but when dila∣ted by the heat of the day, doth take in again. But I fear that in this case, we are vainly employed in searching for a true cause of a meer figment; see∣ing that ARRIAN, CURTIUS, PLINIUS, MELA and other Historians and Geographers, who give the description of this Fountain, did never see it, and had only by report whatsoever they relate con∣cerning it. Every body knows how basely the Priests of Jupiter Ammon did flatter Alexander, when he visited that Temple, and therefore we cannot think strange if they made him believe many things, which they feigned, or by some im∣posture represented to him, to make him conceive a greater veneration for the place and them. And therefore I think it is but reasonable that we should be fully assured of the truth of the thing, before we trouble our selves about searching out the cause of it.

IX. What is the reason of the heat that is found in Well water in the Win∣ter season. Well water in Summer is cold, and in the Winter hot, or at least somewhat luke warm.

This cold and heat doth not proceed so much from the water, as from our Sense, which finds the water colder in Summer than Winter. For when we touch any thing with a very cold Hand, it appears warm to us; as those things feel cold, which we touch with a hot Hand. This we ex∣perience when we enter into hot Baths, which are distinguisht by several Degrees of heat; for when we are enter'd into the first Bath, we think it warm, because our Body is yet cold, but when we return again from the hottest Baths to the first where we entred, we take that to be cold then, and not hot as we thought it was at our first en∣trance into it. And the same is the case of Grot∣tos and Caverns, which always are of the same temperature, but are thought to be cold, because in the Summer we come into them out of the hot Air, in comparison of which they seem cold to us: And in the Winter seem hot, because the Ex∣ternal Air is much colder, than those Grottos or Caves are, with respect to which we think them warm. As before hath been shewed by the Ex∣ample of Oil.

X. The steam that lies up∣on the wa∣ter doth not commu∣nicate any heat to it. We must not conceit, as some Peripateticks do, that the steam which in the Winter time appears upon Well water, doth impart any heat to them, because that steam when felt by the Hand, will be found as cold, as the Air that surrounds it: Whereas the water it self will be found to be hot; which is a sufficient proof, that the water bor∣rows no heat from the steam that lies upon it. Moreover we find as much steam lying upon the surface of hot Baths, as upon Well-water, and yet no body will say, that this heat which is in those hot Baths, proceeds from the said steam or vapor, seeing that it scarcely covers the water, and dis∣appears in a Moment. The reason therefore why Well-water in Winter time seems to be hot to us, is, because we come to it from the External Air, which is many Degrees colder.

XI. Of Springs that make the Persons that Drink of them, Drunk, and others that make the Drinkers to run Mad. The water of some Springs does inebriate like Wine or other strong Drink, and this effect is attri∣buted to the River Lethe, which being drunk of too freely, does produce the same effect as, Wine does. Others again being drunk cause Madness, or Dull stupidity.

The cause whereof must be ascribed, to the Jews-lime wherewith those waters do abound. For Jews-lime, doth strongly affect the Brain, and by obstructing the Pores of the Nerves, doth dull and stupifie the Senses; much in the same manner as the seeds of wild Parsneps, (as AGRI∣COLA tells us in his 2d Book of things flowing out of the Earth) being wrapt in a thin Linnen, and put in Wine do; as also the powder of the Flowers of Hermodactils, which being put into Wine, do presently, and strongly inebriate. And thus Jews-lime being mixt with water, doth ine∣briate those that Drink of it, and makes the Body heavy and lumpish.

XII. A Fountain that makes the Drink∣ers of it to hate Wine. We are told of a Fountain in Arcadia, near the City Clitor, and from thence called Clitorius, which makes those that Drink of it to have an a∣version for Wine, as Ovid assures us.

Who with Clitorian Streams his Thirst allays, Doth Wine abhor, and water Drinks always.

The Reason is, because, as Wine doth cause a nauseousness, not only to those that are drunk, but also after that they are grown sober; so those who drink of those Fountains, impregnated with Jews-Lime, and having had their Heads clouded and troubled thereby, become affected after the same manner as those who are sick of an Ague, and abhor VVine and the smell of it.

XIII. Some Dis∣eases are cured by Medicinal Waters. Some VVaters are endued with a Medicinal Vir∣tue, and are made use of by Physicians for the cu∣ring of several Diseases.

The waters derive this their virtue, from some Metalline or Mineral Matter which they pass through, as Brimstone, Salt, Vitriol, Alome, Nitre and Jews-Lime. And hence proceeds that great variety which we find in VVaters; for Sulphurous VVaters do heat and attenuate▪ Bituminous do dull and cloud the Brain; Aluminous do dry moist and running Sores; and Vitriolick do ad∣stringe. Some of them are immediately conveyed to the Bladder and Urinary passages, by opening and dilating the pores that make way for the said water to pass to those parts.

XIV. Of pretend∣ed Miracu∣lous Foun∣tains. As to those Fountains, of which many Mira∣culous Effects are reported, we may take it for granted, that their highly extolled Virtues are com∣monly grounded upon the reports of some poor People, who are many times set on by others, for Mony, to tell many Lies concerning the Miracu∣lous Effects they have performed. For whatever some may talk, there is no Universal Remedy, or such as is able to cope with, and overcome all Diseases. And seeing that great numbers of Peo∣ple do drink, or otherways make use of these Mi∣raculous Fountains; those that suppose themselves to have been benefited by them, do extol them; when in the mean time we hear nothing of those to whom they have been of no use at all.

CHAP. IV. Of Fountains and Rivers.

I. How Foun∣tains come to spring on the top of Mountains. NOthing is more frequent, than to see Springs break forth from the Bowels of the Earth, and mounting upwards, contrary to the natural weight of Waters, to make their way through the tops of Mountains.

Different Reasons are given by several Men of this Eruption of Fountains. Some suppose that the subterranean waters do mount upwards through certain Pipes or Channels, much in the same man∣ner as the Blood in the Body of an Animal is conveyed through the Veins to all the parts of it, to the Head, as well as to the Feet. This Opi∣nion PLINY seems to favour in his 2d Book, Chap. 65. For seeing that the Earth is dry and thirsty, and cannot consist of it self without Moi∣sture; nor the Water neither without the Earth, supporting and containing of it; it seems necessary that we admit some Veins, through which the Wa∣ter may be conveyed, and get up to the tops of the Mountains. But yet it does not seem probable that the water should be this way conveyed in the Earth, as Blood is in the Body of an Animal: For tho' the water be driven out of the Sea into the subterranean cavities, and by this force im∣prest upon it, do continue to mount upwards; yet no sufficient Reason can be given, why the water, by that time it is risen as high as the surface of the Sea, should not stand still there, or fall back again, seeing that the force wherewith it was pusht upwards, now ceaseth.

Whereupon it seems more likely, that the ori∣ginal of Fountains ought to be ascribed to Vapours, or particles of Water, separated from each other by the force of subterraneous heat. For seeing that under Plains and Mountains great Cavities lie hid, that are filled with water, it cannot be questioned but that a great part of them are con∣tinually resolved into Vapours, and sublim'd to the surface of the Earth, and the tops of the highest Mountains; which by succeeding Cold being af∣terwards turn'd into water again, cannot return back the same way by which they mounted, and therefore find out other open passages between the Intervals of the Crusts or Shells whereof the Earths surface doth consist.

II. Why some Springs flow equally at all times▪ and others not. Some Fountains flow continually, and much with the same force, and abundance of waters; whereas others are subject to a great decrease in Summer and Autumn, and some do wholly dry up.

The reason of this decrease in some Springs is, because the pores of the Earth are very open du∣ring those Seasons of the Year, by reason of the Heat that dilates them; and by this means furnish the Vapours a ready and open way to fly away, and mingle with the Air, and therefore can no more supply the Spring with water, as they did whilst they continued shut up within the Earth. And it sometimes happens, that this Evaporation is so great, as to dry up the Spring altogether. But as to those Springs, that flow continually, and much with an equal force, the reason of their per∣petuity is, because the Channels by which their waters are conveyed, are so deeply lodged in the Earth, the Summers Heat cannot reach them to dilate their Pores: which is the reason why the Vapours, being always furnish'd in the same quan∣tity, must also produce an equal and continual springing, or flowing of the water.

III. How Foun∣tains of Oyl are ge∣nerated. Hence it is also, that in some hollow parts of the Earth, Oyl breaks forth instead of water, viz. when the Heat, that is in the Bowels of the Earth, is of force enough to lift up thick and gross Ex∣halations; which meeting with the cold parts of the Mountain, become thereby condensed, and joining together, constitute a thick Liquor, very like Oyl. Thus we are told of a Valley in Alsatia, called Leberthal, from whence there breaks forth a fat and thick Liquor, which Waggoners make use of to grease their Wheels. In Scotland also, 2 miles from Edinburg, there is a Spring, the surface whereof is covered with a Black Oyl, which the Inhabitants make use of to soften their Skins, and to heal the Chops and Roughness of it. So like∣wise amongst the Antients, the River Liparis, in Cilicia, was very famous, because those that bathed themselves in it, were as good as anointed with the water of it, which was so soft and Oily. But such Springs as these are very rare, forasmuch as thick exhalations do arise with much more difficul∣ty than watry vapours, and stand in need of a great degree of heat to raise them to the surface of the Earth.

[illustration]

Book. 2. Part. 4. Chap. 4▪

G. Freman▪ Inv.

I. Kip Sculp

To the Right Wor∣shipfull S^r. Basil Firebrace Knight, Alderman and Sheriff of the Citty of London Anno Domini j688.

This Plate is humbly Dedicated by Richard Blome.

* 1.2 Spring-water is generally fresh, without retain∣ing ought of the saltness of the Sea, whence it is derived.

The Reason is, because the fresh particles of the Sea-water are most proper for sublimation, as be∣ing both thin and limber; whereas the saline par∣ticles, being stiff and hard, cannot be changed in∣to vapours, nor pass through the crooked and winding pores of the Earth. Fountains therefore are fresh, because they consist only of those parts of the water that have been strained through the narrow pores and windings of the Earth▪ or that have been sublimed into Vapours by the force of Heat.

V. The Origi∣nal of Salt Fountains. There are some Salt Fountains in France, as near Caen and Bordeaux, besides several here in England; and a great many almost every where upon the Coast of Africa; in the East Indies, near Cormandel, almost all the Wells are Salt. So likewise in the Island of St. Vincent, many of these Salt Springs are found: and on the Shoars of Peru, several Salt Lakes. Besides all these waters which had their original, either from an inundation of the Sea, or by some inlet from the Sea; such is that Lake in Holland, commonly called Haerlem-Meer. There is also a Salt Lake in the Island of Madagascar, and in that of Cuba, which is 2 Leagues in compass, and is not far distant from the Sea. Now the cause of these Springs and Lakes is, because the passages of the Earth, through which their water is conveyed, are very large and open, so that very few or none of their Saline Parti∣cles can be strained from them; or else because their waters pass through some Saline Veins, and so be∣come impregnated with Salt.

VI. Why some Springs a∣bound with water in the Winter, and in Summer are dried up. Some Springs run copiously all the Winter long, but during the heats of Summer, their waters fail and run no longer.

Such Fountains as these, owe their Rise to Rain and Snow, which supply them with their current. For there are many great Caverns under the Earth, and especially under high Hills and Mountains; which being fill'd with Rain and Snow-water, do, according to their largeness, in a longer or shorter time, exonerate themselves. And thus we find, that after long and contiued Rains, new Springs are seen to break forth; which upon great and long continued Heat and Drought, are dried up again, until the said Caverns be supplied again, and filled by frequent Showers, or the melting of Snow, and so begin to run as before. Thus we read, that in the time of Elias the Prophet, the Springs were all dryed up; for the Doors of Heaven being shut up, neither Rain nor Snow fell down upon the Earth, to supply the continual expence of the said Springs.

VII. Why Rivers cannot run but on a shelving ground. All Rivers have their Current from a shelving ground, and where they lie upon a perfect level, they continue unmoveable.

The Reason is, as before hath been hinted, be∣cause those parts of the water that are uppermost, do by their weight press those that lie under them; which being fluid, and readily giving way, slide downwards, where they have more room to spread themselves, and are not so much straitned. For a shelving ground, or down-hill, is, as it were a continued Range of Perpendicular Lines, in which the water cannot be pressed, but it must fall upon the bottom of the shorter perpendicular. For if the Channel, along which the Rivers run, were not shelving, no reason could be assigned, why they should run this way, more than that way; more towards the East, than towards the VVest. Moreover, the Sea, when it swells with the Tide, would be of an equal altitude in the Rivers, in case they did run along an Horizontal Plain, and not along a shelving ground.

VIII. From the Course of Rivers, we know the Altitude of Places. Thus from the Springs and Current of Rivers, we know that some parts of the Earth are lower than others. Forasmuch as that part of the Earth, to which the water flows, is lower than from whence it flows. Hence it is that we know Bo∣hemia to be higher than Holstein, from the Cur∣rent of the Elbe. And thus likewise from the Da∣nube, Visurgis, the Rhine, the Maes, &c. we take our Judgment of the Altitude of the several places through which the said Rivers pass. Thus Swit∣zerland and the Country of the Grizons, are count∣ed by some to be the highest ground of Europe, because the Rhine, the Rhone and the Danube pro∣ceed from them. Now as great as is the Down-hill of these Rivers, so great is the altitude of the Mediterranean places, above those on the Sea∣coasts.

IX. What is the reason of the swift current of Rivers. And the greater the Down-hill or Declivity of the Channels of Rivers is, the swifter is their Cur∣rent; and the less it is, the slower is their Course. And the same thing is the reason▪ why one and the same River, runs more swiftly in one part of its Course than in another, which is observable in many places of the River Rhine. For if the bot∣tom of a River, within the compass of 200 paces, lean down one pace, the water runs so swiftly, that it cannot be navigated without danger. In those places therefore where there are Cataracts, or Downfulls of Water, there the Rivers run with the greatest swiftness. And therefore it is that Brooks run with that violence, because they are precipitated from the tops of Mountains.

X. Whether the Course of Rivers be always towards the West. All great Rivers flow towards the West, and none of them towards the East.

This hath been generally believed, but without sufficient ground; seeing it is evident, that the Rhine, the Nile and Ob flow towards the North; the Rhone, and the River Indus, towards the South; the Danube, the River of the Amazons, and that of St. Laurence, towards the East. Whence we conclude, that Rivers do not tend to one particular part of the World, but are indiffe∣rently carried to any part of it.

XI. How it comes to pass that fresh water sometimes springs in the midst of the Sea. It is sometimes found that fresh water springs in the Sea, tho' not far from the Shoar. Yea, some Historians assure us, that in the Province of Juca∣tan, in America, a vein of fresh water springs a cubit high, above the surface of the Sea.

The reason whereof is, because the Receptacles of water that are in the neighbouring Mountains, have their vents or out-lets so disposed, as not to tend upwards towards the top of those Mountains, but downwards: So that the waters flowing out from them, do meet together with a large Chan∣nel, where they constitute a Spring or Fountain; and therefore must needs break forth in some low place, that is, from the bottom of the Sea; and because their eruption is forcible, they spring some∣time above the surface of the Sea-water. The reason why some Rivers, running into the Sea, do for a great way retain their freshness is, because

their Current is so swift and violent, that they push back the Sea-water, and keep it from mingling with them, till at last, by a longer process, their force being weakned, they mingle with the Salt-water, and are lost in it.

XII. The Cause of the con∣stant Inun∣dation of the River Nile, after the Sum∣mer Sol∣stice. The River Nile, which is but 18 foot deep, doth sometimes swell to the height of 18 Cubits, that is, 27 foot, and at other times to 12 Cubits: And this Inundation is so constant, that it always happens at a set time, that is, presently after the Summer Solstice.

The Common Opinion of the Antients was, that this swelling of the Nile was caused by the anniversary winds, called Etesiae, which did blow about that time; and driving against the mouths of this River, did stop the vent of its waters into the Sea, and by consequence made its Channel to swell, and run over its Banks; according to the account the Poet Lucretius gives us of this Inun∣dation, in his 6th Books.

In Summer Nile o're-flows, his Streams do drown The Fruitful Egypts Fields, and his alone; Because the Mouth of that wide River lies Oppos'd to North, from whence th' Ethesia's rise▪ From heavy Northern Clouds, and fiercely blow Against the Streams; those stop, and rise, and flow.

But this doth not seem to be the genuine cause of the overflowing of Nile; since it is certain, that the Nile sometimes overflows, before that these soft winds begin to blow, and consequently before they can stop the Mouths of it, in order to cause the said Inundation. And that this over∣flowing ceaseth, before they cease to blow, and to drive its waters upwards, as is supposed. Where∣fore the cause of this Inundation may, with more ground be ascribed to the great and frequent Rains that fall in Ethiopia, from about the middle of June, till September; because the time of their Winter is from the end of May, to the beginning of September. And in like manner, the River Pa∣raguay, or as the Spaniards call it, Rio de la Plata doth overflow, at the time when great Rains fall on the Mountains of Peru, which obligeth the In∣habitants for 3 Months to live in Boats.

XIII. What is the reason of the sud∣dain rising and va∣nishing of some Foun∣tains. It is observed, that Fountains do sometimes, all on a suddain, break forth on the Mountains, which were never seen before; and that others on the contrary, do as suddainly vanish and disap∣pear.

This sometimes is caused by Earthquakes, where∣by the hidden Sources of Springs are broken up, and the obstacles that retain'd and kept them from breaking forth, are removed. And they dry up, and suddainly disappear, when some new obstacles are cast up to stop their way; or when the water is sunk down into such deep Caverns, from whence it can no more be elevated: For in this case it is forced to change its course, and turn aside another way. Who does not know that a vast heap of waters is hid in the hollows of Mountains, which being opened by an Earth∣quake, way is made for the said waters to break forth?

XIV. Why some Rivers run under Ground. Some Rivers, in the midst of their Course, run and hide themselves under ground, and afterwards start up again like new Rivers. Thus the River Niger, in Africa, which some suppose to be de∣rived from the Nile, by a subterraneous passage, by that time it meets with the Mountains of Nu∣bia, runs down under ground, and breaks out again on the VVest side of the said Mountains.

The Reason of this is twofold. 1st. The ob∣stacle of a higher ground than is the bottom of the River. 2dly. The Hollow that is under the ground, at the place where the River hides it self, or the looseness of the ground, which easily gives way to the force of the River. Thus the River Tigris, in Mesopotamia, after it hath pas∣sed the River Arethusa, meeting with the Moun∣tain Taurus, runs down into a Cave, and ariseth again on the other side of the Mountain; and afterwards having passed the Lake Thespis, hides it self again under ground, and riseth up again about 6 German miles farther.

CHAP. V. Of the Sea.

I. Why the Sea seems to be higher than the Earth. THE great Mass of the VVaters of the Sea, appears higher than the Earth, and seems to be raised much above the surface of it. And therefore to those who take a prospect of the Sea, from the Shoar, the Sea seems higher than the Land; and when from the Sea, they look to the Shoar, that appears lower than the Sea.

Some persons, measuring all things by their Eye-sight, suppose the Sea, because of the same convexty it hath with the Earth, to rise by de∣grees above the Earth; and that it is not only higher than the ground or bottom of the Earth that supports it, but is also higher than the Islands and Continents. But this is no better than a de∣ception of the fight, which reaching forwards to∣wards the more remote parts of the Sea, is di∣rected towards them by Rays, which the more they recede from a Perpendicular, the further di∣stant and higher it represents them. This we find by experience, not only in the Sea, but in any great Plain. And on the other hand, the reason why the Shoar, beheld from the Sea, ap∣pears lower than it, is because the height thereof is contained in the least Visory Angle, which the Roling Waves do intercept, and take away the sight of; so that it is no wonder if the Shoar seems to be more deprest than the VVater.

II. That the VVater is not higher than the Earth, pro∣ved. But besides this, we have a very convincing Ar∣gument to prove, that the Sea, setting aside the swelling of its VVaves, is not higher than the Earth. For this supposed, it must follow, that the VVater, by its natural gravity, would over∣flow, and quitting the upper part of the Earth, would only take up the lower. Or forasmuch as the parts of the VVater do push forwards one ano∣ther, and the upper parts press those that are un∣der them, the whole surface of the Earth would presently be covered by them, and both Islands and Mountains be overwhelmed by the Sea. Be∣sides, how would Rivers be able to return to the Sea, if the Sea were higher than the Earth; and if the surface of the Earth were lower than that of the Sea? For nothing that is heavy does natu∣rally tend upwards, as every Body does that tends to a Body, that lies higher than it self.

[illustration]

Book. 2. Part. 4. Chap. 5▪

G. Freman. Inv.

I. Kip Sculp▪

To the Honourable S^r. Ralph Delaval, of Seaton-Delaval in Northumberland Knight, one of the Comissioners for Ex∣ecuting the office of Lord high Admirall of England; and joint and Seperate Admi∣rall of their Ma∣jesties Fleet.

This Plate is humbly Dedicated, by Richard Blome.

* 1.3 And therefore it was a vain Fear into which the Mathematicians cast the Kings of Egypt, when they dissuaded them from cutting a Channel from the Red-Sea into the Nile, or the Mediter∣ranean; supposing the Red-Sea to be 3 Cubits higher than the Mediterranean, and that therefore a Deluge would be the consequent of that Enter∣prize. For indeed, had the Red-Sea been only one Fingers-breadth higher than that part of the Medi∣terranean which washeth the Shoars of Egypt, the whole compass of Africa, would not hinder it from running thither, till both Seas were reduc'd to a Level. Thus, because th Caspian Sea is higher than the Euxine, therefore it empties it self into it: And because the Euxine-Sea is higher than the Aegean or Archipelago, therefore it falls down into it.

IV. Aristotle's Mistake about the height of the Sea. This discovers ARISTOTLE's Error, who asserts the Ocean and the Earth, to be higher to∣ward the North, than about the Aequator; be∣cause the Ocean seems to flow from the North parts of the World, as from its Head or Fountain. But indeed, nothing of certainty can be thence inferr'd: For it is doubtful as yet, and hath never been suf∣ficiently proved, neither from that motion can it sufficiently be cleared, whether the Northern Countries, and more particularly the Channels of Northern Rivers, be higher or lower than the Channels of those that are about the Aequator. The Reason is, because this motion is not General or Universal, as not being found in all Northern Countries. And tho' we should grant this motion of the Ocean from the North, yet doth it not follow from thence, that the Ocean there is higher, because it is to avoid this greater height, that the Sea flows from the North towards the Aequa∣tor.

V. VVhy a Ship can∣not without difficulty be brought out of the Haven into the Sea. But some Body may Object: If it be so that the Sea is not higher than the surface of the Earth, how comes it to pass, that it is more hard to get Ships out of the Haven into the Sea; than it is to enter into it from the Sea?

I Answer, That the Reason of this is, not because the Sea is higher than the Earth; but because when a Ship is getting out of the Haven, it hath but little Wind, because the Shoars and Banks break the force of it, and hinder it from rushing with a full swing against the Sails▪ Whereas, when a Ship enters the Haven, nothing hinders the Wind from coming with full force against them.

VI. How it comes to pass that the Rivers return to the Sea. Rivers continually exonerate themselves into the Sea, and having past through several Tracts of the Earth, return to it again; and yet the Sea is never increased by this accession of the VVater of innumerable Rivers, that continually, without ceasing, run into it.

The Cause hereof is, that continual Change, whereby the Sea-water is turned into Vapours, and they again changed into water. For as we see in an Animal, that the Blood runs out of the Hollow Vein into the Heart, and presently after is from thence dispersed through the Great Artery, to all the parts of the Body: So the Vapours arising from the Sea, are conveighed through the Passages of the Earth, to the tops of Mountains, and there being condensed by the Coldness of the place into water, become Springs, and afterwards Rivers; which through the slanting places of the surface the Earth, are carried again towards the Sea, which is the place from whence they first pro∣ceeded: So that as much water as is thus evapo∣rated from out of the Bowels and Caverns of the Earth, so much flows into them again from the Sea; and as much as runs from the Sea through these subterranean Passages, so much the Rivers return to the Sea again.

VII. VVhy the Sea always preserves the same degree of saltness. Neither is it any matter of wonder, that the Water of the Sea continues salt, notwithstanding she receives the Fresh-water of so many Rivers into her Bosom: And so much Salt-water conti∣nually flows from her into the Bowels of the Earth, and which leaves its Salt in the places where they are distill'd into Vapours. For besides that the Sea-water may be conveighed into the Earth to those places where it is thus distill'd, by such large and open Passages, that the water which is left after the Evaporation, may carry back all the Salt which it could not elevate, into the Sea; the water which runs continually through the Mines of Salt, do carry along with them at least as much of it to the Sea, as the Sea-water conveighs into the Bowels of the Earth: Whence it is evident, that the Sea must always keep its saltness, as we see it doth.

VIII. VVhy the Sea is found to be more salt in the heat of Summer. In the Heat of Summer the Sea is found by Experience to be Salter than at other times: Which they who live under the Aequator and Torrid Zone are very sensible of.

The Reason is, because the Sun, which is ex∣tream hot in those parts, doth evaporate the thinner and fresher parts of the Sea, leaving the more thick and gross parts behind. And the more vehe∣ment this heat of the Sun is, the more are the outward parts of the Water agitated, and a greater abundance of Vapours are sublim'd; which being condensed in the Air, and reduced again to water, do not always fall down in the same place from whence they proceeded; but frequently having taken a large turn in the Air, fall down to the Earth, at a great distance from the place of their first elevation. An Example whereof we have in Salt-water that is boyled over the Fire, which the longer it is boyl'd, the salter it grows; because the fresh particles are continually exhaled from it.

IX. How it may be prov'd, that our Spittle is salt. Hence it is that our Modern Physicians suppose our Spittle to be salt and sowrish; for when we spit upon a hot Briok or Iron, it leaves a white Spot behind it, which is nothing else but a colle∣ction of saline particles, that because of their Stiff∣ness and Heaviness, could not fly away together with the watry particles.

X. VVhy the Sea is more salt betwixt▪ the Tro∣picks, than elsewhere. The Reason why the Sea is more salt betwixt the Tropicks is, because the Sun dispenseth more heat towards the Aequinoctial Line, than in places at a farther distance from it, and conse∣quently resolves more of the Particles of fresh water into Vapours, and by the extraction of them leaves the Sea-water salter than it was before. To which may be added, that the Sea is of a far greater extent between the Tropicks, than in the Frigid and Temperate Zones, and less Rivers empty themselves into it.

XI. VVhy Sea-water near the Aequa∣tor is more proper for Salt, than others. And from hence we may easily perceive the Reason, why the water of the German Ocean, and of other parts of the Northern Sea, is not so good to be boiled into Salt, as is the water of the

Spanish Sea, the Canary Islands, and Cape Verd, or the Green Promontory in Africa; viz. because th••se last parts of the Sea are nearer to the Torrid Zone, and receive its waters from the Ocean of that Place. But yet it cannot be deny'd, but that some of these Seas are more proper for the making of Salt, than others. Thus the Sea-water that is upon the Coast of Guinea, in the Aethiopick Ocean, doth at one boyling afford a Salt as white as Sugar, such as neither the Spanish-Sea, nor the Sea-water of any part of Europe can afford at the first boyling.

XII. How Sea-water may be made fresh. Dig a Pit on the Sea-shoar, a little higher than the Tide reacheth, and as deep as the lowest Sea∣mark; and when the Tide comes in, you'l find it fill'd with Fresh-water. This is an Experiment commonly try'd by the Inhabitants of the Sea-Coast of Barbary, who have little other Fresh-water, but what they get after this manner.

The Reason of this Experiment is, because the Sea-water loseth its saltness by straining through the Sand, between which it leaves its Corner'd parts, which are the cause of its saltness. But yet it is not necessary, in order to the ridding of Sea-water from its saltness, that the pores through which it is strained, be extream strait and narrow; for if they were so, they would presently be stopt up, by the first saline Particles that entred them, and so there would be no way left for the particles of the Fresh-water to pass. But it is rather ne∣cessary, that the Sea-water be strained through those Bodies, whose pores are large enough, and full of Corners and Windings, proper to stop the particles of Salt from running along with the Fresh-water. It is also necessary, that the Body through which it is strained be large enough, that so, since it can rid it self of the Salt all at once, it may have a sufficient space to drain through, to rid it self thereof by degrees, by passing through the several Crooked windings of it; and therefore some time is required, before the Sea-water can pass through that space, which is necessary by fil∣tration to separate its Salt from it.

XIII. VVhy the Sea-water is salt. Reasons may also be assigned, why it pleased the Creator of all Things that the Sea should be salt; viz. 1st, That it might not be apt to pu∣trifie, corrupt and stink. 2dly, That the Sea-water might not be so easily resolved into Vapours, as the Fresh is, by reason of the Heaviness the Salt imparts to it. 3dly, That the flesh or sub∣stance of the Fishes, that breed and live in it, might be the firmer. 4thly, That it might be the more able to resist the violence of Winds and Storms. For Salt-water is more firm and con∣sistent, than Fresh. 5thly, That it might be the better able to resist cold, and not be so easily frozen, as Fresh.

XIV. VVhy the VVater of the Sea runs VVest∣ward. Constant and known Experience hath informed Sea▪men, that the Sea moves from East to West: So that by this means Ships have a shorter or more speedy Navigation to the West-Indies, than to the East. And all Navigations to the East, are found more difficult, and take up more time.

This proceeds from the Inequality of the parts, whereof the Earth and Water do consist. For tho' this Terraqueous Globe, by its Diurnal motion, moves from West to East, about its own Center; yet because the Earth is more solid and heavy than the Water, therefore it is whirl'd about its Center more swiftly, than the water: So that the water, which is more slowly carried about, seems to move towards the West; in like manner as a Boat, that moves more slowly towards the same place, appears to tend the quite contrary way to another Boat that moves more swiftly.

XV. This mo∣tion is only per∣ceptible between the Tro∣picks. This motion of the Sea-water from East to West, is most perceived between the Tropicks, and in the Torrid Zone; because tho' the Earth be Spherical, yet because that part of its Roundness which is between the Tropicks, is whirl'd about with the greatest force towards the East, as being furthest from the Poles; whereas that part which is without them, because of its nearness to the Poles, is moved more slowly, therefore it is that this motion is only perceptible between the Tro∣picks.

XVI. Of Cur∣rents ob∣served in the Sea. Besides the General motion of the Sea, which belongs to the whole Mass or Body of it, there are also several particular motions observed in it, which are called Currents; whereof some happen constantly at certain Seasons of the year, but others are not subject to any fixt time. They that Sail to the East-Indies, observe some very swift Currents in their way thither: For tho' the Tide, in those Seas, do not rise above 2 or 3 Foot; yet they extend themselves the space of 12 or 13 Hours towards the North, and the rest to∣wards the South, with such an extream Violence, that it sometimes breaks the strongest Cables of Ships lying at Anker.

XVII. The Cause of certain and fixed Currents. There be 2 sorts of these Currents, the one constant and fixt, the other inconstant and irre∣gular. It seems probable, that the constant Cur∣rents that are observed between the Tropicks, do proceed from hence, because the waters that run Westward, are more straitned in some places, than in others; either because the Bottom of the Sea is more deep there, or because of a range of Rocks in Parallel Lines, which oblige them to follow their direction. And as to those Currents that are found without the Tropicks, and which continue always the same, it is very likely that they proceed from some Rivers, which continually discharge themselves into the Sea. For as there are some Rivers which appear above the Earth; so there are others also that lye hid, and which flow beneath the surface of it.

XVIII. The Cause of incon∣stant and irregular Currents. As to those Currents which are Incertain and Irregular, both as to the time, and the determi∣nation of their motion, they seem to be caused by the Unevenness of the Bottom of the Sea, by reason of divers Rocks ranged in Lines, differently tending towards the 4 Principal parts of the Ho∣rizon. For this supposed, whenever there is a stiff Gale of Wind, it must needs drive the water forceably between these Rocks, and by so doing must force them to take a Course by so much the more violent, as the Wind is stronger, and the space betwixt the Rocks straiter.

XIX. The Sea-water can bear more heavy bur∣thens, than the Fresh-water. The Sea-water doth more powerfully resist the Bodies that are put into it, than River-water: As we see that sometimes those Ships which were born up by the Sea, do sink in the River or Haven.

The Reason is, because the water of the Sea is more heavy, as consisting of more thick and solid Parts, and which may lye in a less room, and therefore are more able to bear the burthens put

upon them. This is most evident in the Dead-Sea, which because of its extream saltness, will buoy up a Man, that is cast into it with his Hands and Feet bound. HIERONYMUS FLOREN∣TINUS relates, that he saw a Man that was cast headlong, bound Hands and Feet, into the water, yet was kept up by it for a whole Night: And POSSIDONIUS affirms, that he saw in Spain, Tiles made of an Earth wherewith they scour Plate, swimming on the top of the water. Neither can any other Reason be given, why a Ship draws more water when she Rides in an Haven, than at Sea; but because the water in the Haven is not so salt as the Sea-water, and there∣fore doth not buoy up the Vessel so strongly, as the more Salt-water of the Sea.

XX. Why Wine through a Flannen or Linnen-Bag, of a Conical figure, loseth its strength. This also is the Reason why Wine that is strained through a Flannen-Bag, commonly called Hippocrates his Sleeve, doth lose the greatest part of its strength; because many of those particles, wherein the strength of the Wine doth consist, do continue sticking in the pores of the Filter, by which means the Wine being deprived of them, proves much more weak than it was be∣fore.

XXI. Salt-water is not pro∣per to quench Fire, but rather in∣creaseth it. Salt-water is not good to quench Fire with, for it rather promotes it.

The Reason is, because the particles of Salt, which predominate in Salt-water, being stiff and inflexible, are easily agitated by the Bodies they meet with; and being thus agitated, are very proper to increase the Flame, seeing that of them∣selves they oft produce a flame, when at any time they break forth violently from the Bodies in which they are contained. To this may be added, that the Sea-water is much thicker and fatter, than Fresh-water, and so is more proper to feed and foment the flame, than to extinguish it. It was by this means that the Fire-works cast into MARK ANTONY's Fleet, in the Sea-fight at Actium, did much greater Execution, because the Souldiers not understanding the Nature of Sea-water, endeavouring to quench the Fire kindled in their Vessels, by pouring Sea-water upon the flame, did thereby strengthen and increase it.

XXII. When Fire hath got the Maste∣ry, it is rather in∣creased by pouring a little Wa∣ter upon it. Yea, it may be observed, that tho' Water be very contrary to Fire; yet there be some Bodies, which after they have water cast upon them, do flame so much the more. And therefore it is that Smiths sprinkle water upon their Sea-Coal, to make them burn the more violently. And nothing is more evident, than that a small quantity of water cast upon a strong flame, doth but augment it. But Salt-water doth this with greater efficacy, because of the stiffness of the parts of it, which darting into the flame like so many little Arrows, and hitting against other Bodies, have a great force to shake and agitate them: Which is the Reason why Salts are made use of for the melting and solution of Metals.

CHAP. VI. Of the Ebbing and Flowing of the Sea.

I. The Cause of the Eb∣bing and Flowing of the Sea, is the Moon. THe Sea, in the space of 24 Hours and almost 50 Minutes, does flow and ebb twice.

The Cause of this wonderful Effect, is ascribed to the Body of the Moon, which by pressing the Matter that runs between her and the Earth, doth drive the water also towards the shoars. For as that part of the Street is made more narrow, which hath some part of its breadth taken up by some thick Body; and as that Wind is the strongest and most forceable, which passeth through a nar∣row place; so likewise, because the presence of the Moons Body doth streighten the space that is be∣tween her and the Earth, the Air and the Water, which are fluid Bodies, must needs give way, and rise higher towards the shoar. In the very same manner as we see, that water, or any other Liquor, poured into a Vessel, riseth about the sides of the Vessel, if it be prest by any thing, and leaving the middle of it, is carried towards the Edge of it. But to clear this yet further, let us suppose T * 1.4to be the Earth, and EFGH, the water which compasseth the Earth; B, the Moon, running through her Circle in a Months time; NOPQ, the Vortex of Heaven, which hath the Earth T for its Center, and which together with the Moon is continually whirled about the Earth. For the same Heavenly matter which tends to O, and thence continues its course to P and Q, requires as much space on one side of the Earth, as on the other, and so would press it every where alike. But because the Moon is at B, and doth not move so swift as the Heavenly matter; therefore the said Matter cannot but press the Earth more towards P, than towards O or Q, and consequently the Earth must remove a little from the Center of the Vortex, and come nearer to D; and by this means depress the water which is at F and H. More∣over, because the Earth is whirl'd in 24 Hours about its own Center, that part of it which is now at the Point F, where the Sea falls, within 6 Hours, will be at the Point G, where the Sea swells; and after 12 Hours at the Point H, where it falls again. And forasmuch as the Moon all this while makes some small progress also, and finisheth her Circumvolution about the Earth in the space of almost 30 Days, we must add 12 Minutes of an Hour to the time of each Ebbing and Flow∣ing; so that the Sea takes up 12 Hours and 24 Minutes, in her Ebbing and Flowing, at one and the same place.

II. The Moon is the Cause of this Reci∣procation. Whence it is evident, that this motion of the Sea must be attributed to the Moon; seeing that we find, that the Tide riseth every Day one Hour later, according to the motion of the Moon. For suppose we the Tide to come in to day at 12 of the Clock, to Morrow it will not begin till One, which is a sufficient Argument, that the Tide pro∣ceeds from the Moon.

III. Whence the great difference of the Tides doth arise, The Tide doth not always observe the same time, but comes to some Shoars sooner, and to others later.

This difference may proceed from many Causes; but chiefly from the unevenness of the Bottoms or Channels, wherein the waters are contained, or from the situation and disposition of the shoars, by which the motion of the water is much advanced or hindred. Whereof we have an Instance in the Banks of Rivers, between which the water, according to the diversity of their situation, either runs headlong, or flows gently; goes winding, or else strait along.

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IV. What is the reason of the great Tides that are one the Coasts of Normandy. Hence it is also that they have such great Tides, on the Coasts of Normandy and Britanny, so as that about S. Michael, and S. Macluo, the Tides rise sometime above 60 Foot high. For the Sea being driven from South to North, are beaten back by the British Shoar, and afterwards rebounding from the Coasts of Normandy and Britany they joyn in one Angle, and because of the narrowness of the place do swell and encrease.

V. The flow∣ing of the Sea rends at the same time from the East to the West, and from the Tro∣picks to the Poles. The Tide doth not only tend from East to West, but also at the same time from the Tropicks to the Poles: But yet so, as that in certain places, the one of these is greater and more sensible than the other, which depends on the position or direction of the Coasts. As for Example, in the Atlantick Ocean, the Tide seems only to tend from the Tro∣picks to the Poles, and this because the Coasts of America do resist its motion from East to West. But on the contrary in the Magellan straits, no other motion is perceived but from East to West; because the Coasts there resist the motion from the Tropicks towards the Poles.

VI. Why there is no Tide in the Me∣diterrane∣an. The Reason why only a very small Tide, or none at all is perceived in the Mediterranean is, because it contains many Islands, which resist and hinder it, as also because of the narrowness of its Channel, which does not afford the waters room enough to display themselves in. For tho' that part of the Mediterranean, which is beyond the Tropicks, hath entercourse with the Ocean by means of the straits of Gibraltar; yet because that passage is not above 3 or 4 Leagues over, all the water that can enter this way within the space of 6 Hours, is very inconsiderable, if con∣sidered with the height and breadth of that Sea. And moreover, as soon as the water is entred, it finds the Sea broad, and the Shoars so disposed, that it only moves along the Shoars; and there∣fore it is necessary, that there be only a continual course of the water, without any Flood.

VII. Whence the Tide pro∣ceeds, which is found in the Gulf of Venice. But yet we must here except the Gulf of Venice; for seeing that the waters that are there, being beaten back from the Coasts of the Morea, do soon reach the end of that Channel; it must needs follow that because the first rebounds are second∣ed and supported by the latter, they must cause a sensible Tide, as experience doth witness they do.

VIII. On the Coast of Provence there is but a small Tide. On the Coast of Provence in France, a small Tide only is observed, esecially at the New and Full Moon of the Aequinoxes; for seeing that from that Shoar, to the opposit Coast of Africa, there are almost 8 Degrees of Latitude, without any Island lying between; and because it hath an open way from South to North, the Sea there, about the Aequinoxes, flows about 2 Foot high.

IX. Why there is no Tide in the North Sea. So likewise in the North Sea beyond Scotland, towards Norway and Greenland, scarcely any Tide at all is observed, because that part of the Earth, is at a great distance from the Tract the Moon moves in; or because that Sea is extended from West to East, and is interrupted with many Is••ands, and jetting Points of Land: Whereas in Hudsons Bay, a great Tide is observed, because that Sea lies open from East to West.

X. Why the Tide va∣ries in some places. And much a like account must be given, of that great variety of Tides observed in other places, for that the Sea flows many Foot high at Venice, and at Ancona riseth but little or nothing at all; that on the Coast of Syria, it flows much higher, than in several parts of France, where it scarcely riseth 1 Foot high; the reason of this is, because the Coast of Syria is at the end of the Mediter∣ranean Channel, and those of France about the midst of it; as we find in a Boat, that the rising and falling of the agitated water, is only per∣ceived in the extreams parts of it, not about the midst, where the water is smooth and even.

XI. The Sea water some∣times takes up more time in flowing than in Eb∣bing. Accordingly also, a Reason may be given why the Tide, in the River of Garonne in France, flows almonst 120 Miles, in the space of 18 Hours, whereas the ebbing is performed in 12 only. For if the motion of this Tide be exactly Calculated it will be found, that if the Flood comes in at the New Moon at 3 of the Clock at Mid∣night, it will proceed almost 50 Miles in 6 Hours, that is, by 9 a Clock in the Morning; and after∣wards in so many Hours more, will come to Bor∣deaux, and at 3 a Clock in the Afternoon it turns the Ships about, which shews that the Tide is com∣ing in: And then at 9 of the Clock it reaches as far as the Town of S. Merceur, but is very weak and small there; and without making any stay there, is presently followed with the Ebb, which it is evident must not take up so much time by 6 Hours as the Flood did; because the water by its innate heaviness runs more swiftly to the Sea, than from the Sea into the Rivers. For the Sea be∣ing low, and much deeper than the Rivers, it can∣not be otherwise but that the further the Tide reach∣eth up in Rivers, the more slow must its motion be, because it mounts all the way, and moves up∣hill. For the flowing of the Tide continues, till the water of the Rivers and of the Sea be of one and the same height.

XII. Why the Tide at Havre de Grace in France doth set sooner at the Full Moon, than at Diep. Havens that are under the same Meridian, have not always their Tides at the same time, as is evident in that famous French Haven of Havre de Grace, which at the Full and New Moon hath high water at 9 a Clock in the Morning; where∣as at Diep it is not high water till 10 a Clock, tho' these Havens be but at a little distance from one another, and scarcely differ half a Degree.

The reason hereof is, the many windings and turnings that are in the Channel, which change and turn the course of the water: As likewise the violence of the Winds, which is very considerable there. Thus at Calice and Sluys in Flanders, at Full and New Moon it is high water, about 11 a Clock, the Moon being enlightned on that part which looks Southward; at Arnmuyden and Mid∣delburg, at 2 a Clock in the Afternoon or Morn∣ing; at Zierick-zee at 3 a Clock when the Moon is at South-west, and the Sun enters Capricorn; at Bergen 2 Hours and an half later; at Antwerp and Dort, the Moon being turned toward the Ae∣quinoctial West, almost at 6 a Clock; at Meche∣len at 8, but yet so as that the Tide sometimes comes in faster, and as other times slower, accord∣ing as the Weather is Fair and Calm, or Stor∣my.

XIII. The Tides are greater at the New and Full Moon than at other times. The greatest Tides are at the Conjunctions about D, and at the oppositions about B, that is, at the New and Full Moon, than at the Quarters, or Quadrate Aspects at A, and C. And therefore the Sea men at the New and Full Moon, because the Tides are then greater and swifter, call it a live Sea, and at the Quarters a dead Sea.

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Book. 2. Part. 4. Chap. 7.

G. Freman. Inv.

I. Kip.

To the Right Hon^ble. Henry Lord Viscount Sydney of Shepey, Baron of Milton, L^d. Leivtenant of Kent, Constable of Dover Castle, Lord Warden of the Cinqueports, M^r. Generall of their Ma^ties. Ord∣nance, Collonel of their Ma^ties. first Regiment of foot Guards, one of the Gentlemen of his Majesties Bedchamber, and one of the Lords of their Majesties most Honourable privy Councell &c.^a.

This Plate is humbly Dedicated, by Richard Blome.

The Reason is, because the Heaven A, B, C, D, is not of a Spherical, but almost Elliptical figure, and hath more room in that part of it, which is be∣tween the Earth and A, C, than in the opposit part about B, and D. Now seeing that the Moon when she is about the Quarters, moves in these larger spaces, she consequently advanceth more slowly, and so presseth the waters less, and caus∣eth a less Tide. Whereas at the New or Full Moon, she moves in the narrowest part of her Ellipsis, and therefore causeth a greater pression of the waters, and a greater and swifter Tide.

XIV. What is the Reason of the great Tides that are in the River Seine about the Aequinoxes and Solsti∣ces. It is for the same Reason, that 3 great Tides are observed in the River Seine in France, about the Aequinoxes and Solstices: For the 1st of them riseth almost 4 Foot high, the 2d 8, and the 3d 12 and upwards, and that with so great swiftness, that in 4 Hours it advanceth 25 french Leagues with a great Noise. For seeing that the Tides exceed about the Aequinoxes, and about the Full and New Moon, the motion of the waters must be greater also; and seeing also that the Channel of the River Seine with respect to its Mouth, where it enters the Sea, doth resemble a Trumpet, which grows narrower and narrower by degrees, it cannot be otherwise, but that the waters must rush in with a great force into such a narrow Cha∣nel.

XV. Whether the River Euripus Ebb and Flow so ma∣ny times a day, as some anti∣ent Histo∣rians have le••t upon Record. The River or rather the narrow Sea Euripus, if we may believe the Antients, Ebbs and Flows 9 times a day.

The cause of this effect may also be ascribed to the Interposition of the Moon, by the pressing whereof the River runs down, not towards one part of the World, as the Seas do, but every way; so as that one part goes to the South, another to the North, &c. which as they light upon the Straits of a narrow Sea, or upon neighbouring Shoars, accordingly the Ebbing is hastned or re∣tarded. Tho' indeed we may have good reason to question, whether what the Antients have re∣lated of this River, be all agreeable to Truth; seeing that TITUS LIVIUS in his 8th Book, Decad 3d denies it, and gives us sufficient occa∣sion, to doubt of the faithfulness of Authors as to that Point. The Strait of Euripus, saith he, doth not ebb and flow at set times 7 times a day, as the common report is, but according to the Wind is sometimes hurried this way, and sometimes that way, like a Brook that falls headlong from a steep Mountain; so that it does not suffer the Ships to rest night or day.

XVI. Why there is no Tide in Rivers and Lakes. Rivers and Lakes have no Tides, and receive no change from the opposition of the Moon.

XVII. Nor any Tide in the Dead Sea, nor in the Euxine Sea. The Reason is, because their Banks are not suf∣ficiently distant from one another, nor is their surface large enough to admit the pressure of the Heavenly matter. For even as Vessels the nar∣rower they are, the less motion is perceived in them; so no other water, but the Sea which sur∣rounds the whole Earth can have so much room, as at the same time to rise or swell in 2 several places, and to fall or sink in 2 others. And there∣fore it is that the Rivers, Bays and Lakes that are between the Tropicks, cannot admit of any Ebbings and Flowings.

As to those Lakes and Rivers that are without the Tropicks, neither are they subject to Tides, no nor the Seas neither, that are considerably great, in case they have no entercourse with the Ocean, or if they have any, yet the communica∣tion of the waters, is by a strait and narrow pas∣sage. Thus the dead Sea in Asia, and the Euxine Sea in Europe have no Tides, because they have no communication with the Ocean; neither hath the Baltick Sea any, for tho' it be united with the Ocean, yet the strait of the Sound by which it communicates with the Ocean, is so far turn'd a∣side, from the straight Line, in which the waters move that are driven from the Tropicks towards the Poles, that they cannot enter in sufficient quantity into it, within the time of 6 Hours, to cause any sensible Elevation of the waters.

CHAP. VII. Of Fire.

I. How Fire▪ produceth or propa∣gates Fire. ONE Fire is produced or propagated by ano∣ther.

The Reason hereof is, because the parts of the 3d Element, being carried away by the First that surrounds them, meet with like parts of the 3d Element, which they not only separate from their like parts, but also from those of the 2d Ele∣ment, so that these also being surrounded with the first, are snatch'd away by it. For as a Ship that is carried along by the stream of a River, doth more forceably push forwards other Bodies it meets with, than the River it self can; so these parts of the 3d Element, being hurried along by the 1st Element that surounds them, do agitate more strongly than the first alone can. Wherefore, if the force of these parts that are hurried away by the first be so great, that they be able to push far from them all the parts of the second, which the neighbouring Air is full of, and keep them so; then the Flame appears, as we see in Wax, Grease, Oyl, Brimstone and Gunpowder set on Fire: But if they be not of force enough to do this, then the Fire lies overwhelm'd with much Ashes, as in Leaves, Touchwood, or any other dry Fewel.

II. How Fire is genera∣ted by con∣centration of the Beams of the Sun. Fire is also generated by concentring the Rays of the Sun.

The Reason is, because Light is nothing else but the motion of the 2d Element, produced by the 1st, whereby the 3d Element is made visible. For it may happen, that upon the uniting of several Rays, some part of the 3d, may be separated from its other like parts, and from the 2d, and conse∣quently be surrounded only with the 1st, whose motion it must then follow. Thus in our time Burning-glasses have been invented, by which Metals may be Melted, and Wood suddainly set on Fire.

III. There be some Fires that shine without heat. Some kinds of Fire do shine, and yet are desti∣tute of all heat. For they who use the Sea, ob∣serve that at sometimes when Waves are dasht against Rocks, they appear as if flames of Fire re∣bounded from them. And thus also Rays of Light proceed from Rotten-wood, and Saltfish, but with∣out any sensible heat.

The Reason is, because the Matter of the 1st Element, which is shut up in the Pores of such Bo∣dies as these, tho' they be of force enought to push the Globuli of the 2d Element, and to move the Retina, as much as is sufficient to produce the per∣ception of Light; yet is it too weak, to separate

the Earthly parts from one another, and to excite that agitation in them, which is strong enough to produce heat. Fire therefore only shines, when the Pores of the Terrestrial Particles are so narrow, that they can only admit the first Element, and shut out every thick Body. Thus when the point∣ed Needles, as it were, of Salt do enter the strait Pores of Fishes, and drive thence the Globuli of the 2d Element, so as to be open only for the ad∣mission of the matter of the 1st Element, they by this means make the Fishes Scales to shine like Glow-worms. Historians tell us of a certain Fly in New Spain, of the bigness of a Beetle, called Cocujus, whose Eyes do enlighten the Night like a Wax Candle, so that it serves for a Lanthorn to those that walk by Night, and for a Lamp to burn in ones Chamber; and by the Light whereof one may read or write; and have the same effect when the Insect is dead, as when yet alive.

IV. Some Fires burn with∣out giving Light. Some Bodies afford great Heat, but are distitute of all manner of Light: As the Blood of Live Animals, Horsdung tending to putrefaction, Quick-Lime sprinkled with water, in which things there is a hidden Fire that burns and scorcheth, without the appearance of any Flame.

The Reason is, because in such Bodies as these, the parts that surround the 1st Element, and that are agitated by it, are too soft and limber to trans∣mit the Action of Light. For tho' some of them swim on the top of the matter of the 1st Element; and comply with its motions; yet because some Watry and Aiery plyable parts, are mingled with them, they have the power to kindle heat and fire, but not of receiving the action of Light. Hence it is that when the Spirit of Vitriol and Oyl of Tartar are poured together, an effervescence or boyling is caused, because the free passage of the subtil matter being hindred in them, doth produce a wrestling or contest betwixt these 2 Liquors, which is the cause of a vehement heat. And for this Reason Horsdung, and the Blood of Live Ani∣mals are hot, because the 1st Element is pent up by a softer matter, within the narrow pores of the parts. And therefore they are only hot, that is they have only the force to move those Nerves that are subservient to the Touch, but not of push∣ing the Celestial Globuli, wherein the nature of Light doth consist. Quick-Lime sprinkled with wa∣ter, waxeth hot, because its parts are so suited and disposed, as to admit the water surrounded only with the matter of the 1st Element; so that the Globuli, being expelled, the matter of the 1st Ele∣ment only bears sway. For those Bodies are said to have the form of Fire, whose particles do sepa∣rately comply with the motion of the 1st Element, and imitate the agitation thereof.

V. Why the Flame mounts up∣wards. Flame, by a natural propensity, mounts upwards towards Heaven; and to the end it may the sooner get thither, it quits its thickness, and takes to i•• self a Conical Figure.

It may be said that the Flame doth not so much affect to mount upwards, as it is by out ward force driven up thither; for being on all sides surrounded by the Air, and by reason of its less degree of agitation, as it were, continually beaten by it, it rather tends upwards than down∣wards, because it meets with less resistance there. The way this is performed take as follows. The matter of the 1st Element, which is predominant in the Flame, being in perpetual motion, strives continually to depart from the place where it is; and being lighter than the Globuli of the 2d Ele∣ment, it is carried upwards, and withdraws it self from the Center of the Earth; and forasmuch as no Body can be moved, except some other, by a circular motion, enter into its place, as much Air returns towards the Flame, as there is Smoak that goes from it; and therefore the Air, which, as it were, licks the upper part of the Candle, mixing it self with the parts of the Wax or Tallow, af∣fords fewel to the Flame: So that the power of dilating the Fire, and driving it upwards, may in some sort be attributed to the Air. Now the reason why the Flame is of a Conical Figure, and ends in a sharp point, is evident, because the mid∣dlemost parts of the Flame have more agitation, and consequently move with more force, and are sooner carried upwards, than the outward parts, whose agitation is diminished by the nearness and contact of the Air.

VI. A Pyrami∣dal Figure is acciden∣tal to Flame. From what hath been said, it is evident, that a Pyramidal Figure is accidental to fire, because the Air, by compressing the parts of the Flame, doth form it into that figure. For if we take a Wax-Candle, and place it in an Iron Pipe, and put the said Pipe into a Porringer full of Spirit of Wine, and afterwards set the Wax-Candle and Spirit of Wine upon the fire, we shall find that the flame of the Wax-Candle will be dilated, and swell 4 or 5 times greater than it was, and will then appear of a round, and not of a Pyramidal Figure.

VII. The Fire burns more fiercely in the Winter than in the Summer. In the Winter, when the Air is most comprest and condenst with Cold, the Fire burns most fierce∣ly; and in Rainy Weather, and more especially when the Sun shines upon the hearth more weak∣ly.

The Reason is, because Sulphureous Particles are necessary for the preservation of the Fire, which do break forth from the combustible matter; and Nitrous also, which are mingled with our Air: Now seeing that the Air in Winter, doth most of all abound with these Nitrous Corpuscles, it can∣not be otherwise, but that the greater quantity of these must make the Fire burn more fiercely. Whereas, when the Sun shines upon the Hearth, the Nitrous Particles in the Air are scattered, and consequently the force of the Fire debilitated and almost extinguish'd. Hence it is that when a Lamp or other Light is put into a large Glass, fit for that purpose, as soon as the Air is pumpt out, it is presently extinguish'd; not so much because it is choaked by its own Smoak, as because it wants this Nitrous Aliment contained in the Air.

VIII. Why a Can∣dle with a long Wiek, smoaks more than that with a short one. A Candle that burns with a long Wiek, smoaks more than another that is new snuft.

The Reason is, because in a longer Wiek, the thicker parts of the Candle being mingled with the sulphureous, are without any loss carried up∣wards. But in a snuft Candle, that more fat and sulphureous matter which constitutes the Smoak, by being much agitated in the Flame, is reduced into most minute parts, as may be easily gathered from the crackling noise they make. This is the reason also, why a Plate of Iron, or other Metal being approach'd to the utmost parts of the Flame, con∣tracts only some little smuttiness, because the Ter∣restrial Matter is by the force of the heat reduc'd to so small parts, that they are no longer percepti∣ble

in their egress from the Flame, nor adhere to any Body: But when this Plate is thrust into the midst of the Flame, it is covered all over with Smut and Soot; and that by means of those grosser particles, that are not throughly subdu'd by the heat of the Flame.

IX. How a Can∣dle may be made to burn with∣out smoak. But if a Cotten Wiek be laid to steep 24 hours in Whitewine Vinegar, impregnated with half its quantity of pure Nitre, and afterwards expos'd to the Sun to be dried, it will not send forth any Smoak, because the saline and volatil parts of the Nitre and Vinegar, do so divide and agitate all the moisture, that no part of it can escape the force of the Flame.

X. How two liquors pour'd toge∣ther, pro∣duce heat. Spirit of Vitriol and Oyl of Tartar pour'd to∣gether, produce an Ebullition, or Effervescence.

The Reason is, because the pores of one of these liquors are so formed, that they can only admit the branchy parts of the other liquor, wrapt about with the matter of the first Element; by which means the first Element having repulst the Globuli of the 2d, does alone bear sway. Or because the subtil matter, being wont▪to flow and move other∣wise in the Spirit of Vitriol, than in the Oyl of Tartar, when its free passage is stopt, it causeth a kind of contest between the 2 liquors, and an ef∣fervescence or ebullition by reason of the mutual agitation of their parts.

XI. Why Fire is kindled by a blast. Fire is commonly kindled by a Blast, whether of a Bellows, or otherwise.

Because by this means the Ashes which cover the surface of the Coals, and obstruct their more open pores, is driven away; by which means the Fire that was about to break forth, is driven inward, and there so separates and divides the parts of the Coals, and throughly penetrates them, as to invade and kindle the fat and inflamable particles also. And hence it is that the flame, when blown upon, makes a noise, which is caused by the resistance of its parts, and the mutual combination that is be∣tween them.

XII. How Fire comes to be quenched. Fire is quenched, when its parts are scattered and disperst, as it is kindled by the uniting of them. Thus we find, that either too fierce and violent a Blast of Wind, or a copious affusion of Water, doth dissipate the particles of Fire: The same effect is also caused by a steam that is shut up, and hath no vent to get out by; for then the said Vapour being beat back, and rebounding upon it self, doth divide the parts of Fire. And by this means it is that a Candle is often put out in a VVine Cel∣lar, filled with the steams of New VVine.

XIII. Smoak hurts the Eyes, and moves Tears. The Smoak that proceeds from Wood, makes the Eyes smart, and produceth Tears.

The Cause thereof are the sharp and biting par∣ticles whereof the Smoak consists; which, twitch∣ing the surface of the Eye, and contracting the same, cannot but cause Tears to break forth. For∣asmuch, as by this contraction, the Kernels in the Corners of the Eyes are squeezed, and consequent∣ly let out the humour contained in them. Onions produce the same effect, when they are cut, or otherwise divided into Parts; at which time a sharp vapour or steam proceeds from them; which reaching the Eye, provokes Tears. And probably it is for the same reason, that some Fumes are of use to still the Toothach, whilst by their sharp par∣ticles they do open the pores of the Gums, and not only make way for the Pain-causing Humour to pass away, but also excite it to evacuation. Thus a Fumigation is made with the Bran of Wheat, mixt with fine Sugar, which is found to be of use for this purpose.

XIV. Greek fires, so called, cannot be quenched with wa∣ter. Some sorts of Fire, by Authors called Greek∣fires, cannot be quench'd with water.

These Fires derive this effect from the solidity of their parts, and the swiftness of their Agitation, whereby they beat back the parts of the water. For one of the chiefest things required to the pre∣servation of Fire, is this, that it have a sufficient quantity of earthly particles, which being driven and agitated by the first Element, have the power to hinder the choaking of it by the Air, or other Liquors pour'd upon it. Which force doth most of all abound in Bituminous, Oily and Sulphureous Substances, whereof these Greek-fires are composed. Forasmuch as these, by reason of their Thickness, and the sticking together of their Branchy Parts, are most proper to keep their station, and so to move the water, as to beat back the Aetherial Globuli, which by their irruption might extinguish the Fire.

XV. Why Fire is easily quen∣ched in Wine-Cel∣lars. The contrary hereunto happens in Vaults and Wine-cellers, especially when the New Wine is working in the Vessels; for then not only the Candles that are brought lighted into the Cellar, are extinguish'd, but even Torches also; because their flames being fill'd with the steams of the New Wine, do not consist of any such matter as is able to repress and put by the Air that hangs over them; nor are they strong enough to force it to enter into it self.

XVI. How Fire is to be struck out of Flint, Steel, Stones, and some sorts of Wood. Fire is struck out of a Flint, with a Steel; yea one piece of Steel rub'd against another, doth pro∣duce fire. There are also some Stones, that are called Live-stones, that being struck with a Nail, or hit with another Stone, do send forth Sparks. And in like manner the Indians also procure fire by joining 2 Sticks together, and then take a 3d, which they very swiftly twirl about between them, till they be set on fire.

The cause of this production of Fire is, because when the hard and brittle parts of the Flint, and the other mentioned Bodies, are hit against by a hard Body, many of the spaces, which lie between their particles, and which were wont to be filled with the Globuli of the 2d Element, are made more nar∣row than they were before; and therefore as soon as the Heavenly Globuli are driven away by the force of the said stroak, nothing remains besides the most subtil matter, for to receive these thick particles, and to turn them round very swiftly. And therefore, forasmuch as the parts of Flint are very stiff, and apt to fly into shivers, they do in∣deed give way to the force of the stroak, but im∣mediately rebound again; and thereupon being se∣parated from each other, and hurried away by the motion of the first Element, they turn to Sparks, and constitute the form of fire. And thus in like manner is fire kindled by the vehement rubbing of Sticks against one another; because by this continued violent motion, their particles are first drawn together, and afterwards being with great force separated from one another, whirl round; by which means, not only the parts of the Air, but also the Aethereal Globuli, that surround them, are separated from each other; and being whirl'd round by the vehement agitation of the first Ele∣ment,

turn to sparks, and exhibit the appearance of fire. Thus the Apulians wind Cords about a Stick; and by swiftly twitching them this way and that way, do set them on fire.

XVII. Why Hay, when it is shut up close, grows hot. When Hay is laid up before it is thorow dry, it grows hot, and burns; which never happens when it is spread in a large and open field.

The Reason is, because Hay, whilst it is yet New, doth abound with many Spirits, and seve∣ral Juices; which being accustomed to move thorow the pores of the Green Herbs from their Roots, to their upper parts, do still continue in them for some time after that they are cut down. Which as soon as they are shut up in a close place, the particles of these Juices, passing from one Herb into another, do find the pores of them more narrow than they were, by reason of the con∣traction of their Fibres, so that they cannot enter them, without leaving the Globuli of the 2d Ele∣ment behind them; and being only surround∣ed with the particles of the first, and so comply∣ing with their most rapid motion, are of sufficient force to agitate and heat the thicker parts of the * 1.5Hay. As for Example, if the Interval, which lies be∣tween the 2 Bodies B and C, be supposed to represent one of the Pores of a green Herb, and the small strings 1, 2, 3, surrounded with little round Bodies, exhibit the pieces carried by the matter of the 2d Element; and the Interval D and E, another nar∣row pore of an Herb, that is in part dried, through which the foresaid particles 1, 2, 3, pass, no longer swimming on the 2d Element, but on the 1st on∣ly: It is evident, that those that are between B and C, must follow the temperate agitation of the 2d Element; whereas those betwixt D and E, will be forced to comply with the most swift agitation of the 1st Element. I said, In case the Hay, be∣fore it is fully dry, be laid up in some narrow or close place; because as long as it is exposed in any open place, the juice which runs through the pores of the Herbs, is easily dissipated in the Air, with out passing through the pores of the other strings, wherein it might excite a heat, and cause a Con∣flagration.

XVIII. What the reason is why Gun∣powder is so easily kindled. Nothing is more easily kindled than Gunpow∣der.

The Reason is, because it is compounded of Brimstone, Nitre and Charcoal, which of all things do most easily take fire: For Brimstone, we know, flames immediately, because it consists of particles of sharp juices, which are wrapt about with the thin and close branchy particles of an Oily Matter, so as that many pores between the said Branches, can only admit the matter of the first Element. But Nitre consists of longish and stiff Particles, which being agitated by the particles of Brimstone, do diffuse themselves into a larger space. And see∣ing that the Charcoal also doth abound with many Pores, the Brimstone and Nitre do readily enter the same, and by them are straitned. By which means it happens, that as soon as any fire touch∣eth a grain of Powder, composed of these mate∣rials, it presently enters the same through the pores of the Coals, and presently agitates the parts of the Brimstone, which afterwards move those of the Nitre and Charcoal.

XIX. Some Lamps have been found that have burnt many years in Sepul∣chers. Authors tell us of Lamps, that of old times were used to be put into the Sepulchers of the Dead, and continued burning many ages, without any diminution of their Light. LUDOVICUS VIVES in his notes upon the XXI Book of St. Austin de Civitate Dei, tells us, That upon the breaking open of a certain Grave, a Lamp was found that had burnt 1500 years, but that as soon as it was touched with the hand it mouldred into the smallest Ashes. FORTUNIUS LICETUS also informs us, that about 100 years since, in the Papacy of Paul III, a Lamp was found in the Sepulcher of TULLIA, Ci∣cero's Daughter, but upon the admission of the Air, and Light, was presently extinguish'd.

GASSENDUS reckons these Lamps a∣mongst those Ludicrous Lights, which burn when the Air is shut out, and vanish as soon as it is ad∣mitted; when according to him, they ought to be rather kindled a-new upon the letting in of the Air, and so burn the stronger. But as for my part I see no reason why a fire or flame may not be preserved in subterraneous places, where it cannot be impaired or disturbed by the blowing of the Wind, or the distemperature of the Air. For it may so happen, that the particles of the Soot, which proceed from the Candle or Lamp, may close together about the Flame of the Lamp, and so constitute a kind of little Vault or Arch about it, by which the Air may be kept off from rushing upon the flame, and so overwhelm and choak it. For such an Arch as this would be of use to in∣fringe the force of the flame from kindling the fur∣ther parts of the Oyl or Wiek. So that by this means the 1st Element in such a Lamp, being wrapt up round like a Star, would repel the Aethe∣real Globuli that are round about it, and so diffuse its Light throughout the whole Sepulcher; which tho' but weak and duskish, yet upon breaking in of the Air, and the dispelling of the Soot, which did encompass it, doth discover a bright and shi∣ning Lamp.

XX. A Flame proceeding from Spirit of Wine, doth not burn a Lin∣nen Rag, but only the Spirit of Wine it self. The Flame of Spirit of Wine doth not consume a Rag of Linnen.

The Reason is, because that to the end a Body may be fit to feed the fire, it must have many particles fit and suited to the fire which it is to preserve, and the same so joined to one another, or to other thicker than themselves, that by the dri∣ving or impulse of the particles of the said fire, they may be separated as well from themselves, as from the adjoining Globuli of the 2d Element, and by this means take upon them the form of fire: Whereas the particles of the Linnen Rag are not thin enough to be agitated by the flame of the Spirit of Wine, and to be separated from one another.

XXI. All fat things are not kindled after one and the same man∣ner. For every fire is by so much the more strong and vehement, the more fat and tenacious the matter is that feeds it. Again, amongst fat Bodies, some are much more apt to kindle than others. For Spirit of Wine, the purer it is, and the more highly rectified, the more inflammable it is also, because it hath little or no Phlegm remaining with it. Thus that kind of Stone which is burnt into Quick-Lime, cannot without great difficulty take fire, because its parts being very▪ closely joined together, the fatness that is contained in them, cannot easily be disentangled or driven out from them, to the end it may be kindled into a flame.

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Book. 2. Part. 4. Chap. ••

G. Freman In▪

I. Kip

XXII. What the Reason is, that sparks of Fire sometimes appear upon strongly Rubbing a Cats Back. When a Cats Back is strongly rubb'd with ones hand, Sparks of Fire seem to proceed from it.

The Reason whereof seems to be this, because this Rubbing drives out some Particles of Moisture, and causeth them to be dissipated into the Air; whereupon the particles of the fire, or if you will, the Sulphureous, greasy Particles, wherewith the Hair and Skins of Animals do abound, and those of Cats more than any other, croud and meet together, whence proceeds fire, and from the fire, light. Now this fiery Steam, or Exhalation, is easily retain'd or kept close in this Thicket of Hair, which consisting wholly of Sulphureous filaments, becomes easily entangled amongst the said Hairs. Which is the true Reason, why a Garment lin'd with Fur doth so obstinately retain the heat committed to it, and keep off the Cold. But it is to be noted, that these sparks of Light, which by stroaking are forc'd from the Back of a Cat, do only appear in the Dark, because a greater Light obscures and swallows them, as the Light of the Sun does that of the Stars.

CHAP. VIII. Of Earthquakes, and Subterraneous Fires.

I. The Cause of Earth∣quakes. THe Country of Campagna di Roma, in Italy, Trembled for many days, by an Earth∣quake in the beginning of the year, when L. CORNELIUS and Q. MINUTIUS were Consuls, and that with such frequent and reiterated Concussions, that, as LIVY acquaints us, the People were not only tired and afflicted with the frequent returns of the Earthquake, but also by reason of the Holy-days that were appointed upon that account, to deprecate the Wrath of Hea∣ven.

Some do impute the Cause of Earthquakes to the Sun, as supposing that by his heat, he doth attract those Exhalations out of the Caverns and Holes of the Earth, to the surface of it. But Reason assures us that this cannot be, because the Sun's Rays cannot penetrate so great a Depth of Earth: For tho' the Earthy particles, being beat upon by the Rays of the Sun, do agitate others which are near to them, and to which the Rays themselves▪ cannot reach; and these again, others that lye near to them, and so on; yet is not this Commotion of the parts of the Earth sufficient to kindle a fire in it. Wherefore it seems more Rational for us to attribute the Cause of these Earthquakes to those Exhalations, which mounting through the Chinks and Cavities of the Earth, do there compose fat and thick Fumes, not much unlike to those which proceed from a Candle newly extinguish'd, and fill the whole space that is about it, which by a spark of Fire, either from Flints hitting against each other, or by some Candle that Miners make use of in their labour, are presently kindled; and being thereby vastly rarefied, shatter to pieces all the confinements of their too narrow Prisons, and force all the Bodies that stand in their way.

II. Misnia in Germany, and the Island del Moro, have subterra∣neous Fires▪ that burn in the Bowels of them. Thus AGRICOLA tells us, that in the Country of Misnia in Germany, there is a Moun∣tain of Smiths-Coals that burns continually; where, according as the Flames spread and con∣sume the Coals, the Earth sinks down and leaves deep Holes, which appear like so many burning Furnaces; the flame whereof sets any fit Matter on fire, that is at 4 Foot distance from them. In like manner, in the Island Del Moro, the Fire bursts forth with such extream Noise, that it equals the Thundering of the greatest Cannon, and with so thick a Smoak, that it may be compared with Midnight-Darkness; and with such a prodigious quantity of Ashes and Cinders, that Houses are crush'd under the weight of it, Cattle and other Beasts destroyed, and Fresh-waters turned into bitter.

Now whenever the Exhalations that are kindled in these Caverns, are not of force enough to break their way through the surface of the Earth, they only produce a shaking or trembling, that is, they only cause the Earth that is above them to rise: In like manner as Gunpowder heaves up the Ground under which the Mines are laid: And the said Exhalations appear outwardly, when they have strength enough to open the ground.

III. Why in some Earth∣quakes there be several successive shakings. In Earthquakes, there are many times repeated shakings succeeding one another.

The Reason of this is, because the Matter that is kindled, is not always altogether in one and the same Cavity; but in many, which are only separated by a little sulphureous Earth: And there∣fore when the Fire takes in one of these Cavities, it gives the first shake to the Earth, and a second, when it kindles that which is in the next, after having consumed the sulphurour Matter that did separate them, and so on to the very last Cavity.

IV. An Earth∣quake never assaults the whole Earth, but only some particular parts of it. Some parts only of the Earth are shaken in Earthquakes, not the whole Ball thereof.

The Reason is evident, for that the Exhala∣tions which abound in the Earth, and which have the power of shaking it, do not every where meet with a space wherein to dilate themselves. For since there are innumerable subterranean Cavi∣ties, and various hollows and windings, ready to admit any foreign Bodies, we cannot well con∣ceive them to be all fill'd with the same Matter. For some of them contain Waters, which because of their innate Coldness, and the thickness and foeculency of their parts, do stagnate without any motion. Others are full of a thick and foggy Air, which being pent up within narrow Walls, is never driven out of its Holes without some force. Others again are taken up by fire, or rather fiery Steams and Exhalations; but such as are shut up in their Dungeons, and being unable to break forth, lye very quiet there without doing any mischief. Now these Steams or Exhalations, pent up within the Bowels of the Earth, from the various coalition whereof, Brimstone, Jews-lime, and other such like inflamable Bodies are made, like a smoaking Torch, are kindled either by ano∣ther Fire, or by the striking of hard Bodies against one another, or by the mixture of Liquors proper to produce an effervescence, and a consequent flame; and by means whereof being now more dilated, they push against the sides of their Dun∣geons and shake the Earth, till at last having broke

through their Prison-walls, they burst forth, and rush to take possession of a free and open Career. And forasmuch as these Exhalations are very in∣considerable, and bear no proportion to the whole Globe of the Earth, they can only shake some parts of it, without concerning the whole.

V. What places are most subject to Earth∣quakes. Sea-Coasts of all other places are most subject to Earthquakes, because much fat and slimy Matter flows from the Sea, into the several sub∣terraneous Cavities, which are very proper to feed the Fire. And therefore we find that Earthquakes very seldom are heard of in the Northern parts of the World, especially those that are remote from the Sea; because they have not Matter enough to produce these Concussions, the same being either drawn off by the heat of the Sun, or else because it is but gradually and in small quan∣tities conveyed from the Sea. To which we may add, that in the Parts now mention'd, there are but few subterranean Caverns to admit this Matter: For this loosness of the Earth, and the wide and open Cavities contain'd in the Bowels of it, do much conduce towards the causing of these Earth∣quakes; because fresh Matter is laid up in store in them, for the producing of these Effects.

VI. When and where Earth∣quakes are most frequent. Accordingly we find, that Earthquakes are most frequent in those places where the Earth abounds with Caverns and subterraneous Cavities, which are the proper and fit receptacle for those Exha∣lations; except the said Cavities be open towards Heaven, and so afford a free passage for the Ex∣halations to fly away. Wherefore also Earth∣quakes chiefly happen, when abundance of such Exhalations are found in the Earth; as in the Spring and Autumn.

VII. What is the Cause of the great Noise that is consequent upon Earth∣quakes. Every Earthquake is followed by a Noise, not much unlike that of Thunder, which always ac∣companies, and sometimes goes before it.

The Reason hereof is, because the Fire which is rarefied within the Cavities of the Earth, doth rebound and return upon it self: For seeing that in these Caverns there be innumerable winding Passages, which the kindled Exhalations go through, it cannot be but that the sound must needs be multiplied in its passage through them. Thus we know that Eccho's are most frequent in Caves and Hollow places: And thus we find, that from cer∣tain crooked Horns, which the Musicians from their windings call Serpents, a kind of Lowing Noise doth proceed, which is only to be attributed to those windings and turnings by which the said found is conveyed to our Ears. Every Earthquake therefore is accompanied either with a greater or less Noise, according as the matter is more swiftly or more slowly kindled, and as the rarefied Exha∣lations, do break forth with greater or weaker force, and display themselves by many or fewer Concussions.

VIII. VVhence that great Fire that proceeds from Aetna and Vesu∣vius, is caused. The Earth in many places casts forth Fire through the top of many Mountains: Thus Mount Aetna in Sicily, Vesuvius in Naples, Hecla in Iseland, &c. do disgorge Flames, and cover the Neighbouring Countries with Ashes. The Mountain Vesuvius, now called Monte di Soma, according to the Relation of DION CASSIUS did burn in the year that TITUS VESPASIANUS and FLAVIUS DO∣MITIANUS were the 7th time Consuls, and breaking forth at the top, at first cast forth Stones, and afterwards such a vast quantity of Flames, that 2 Towns, Herculaneum and Pom∣peium were thereby consumed; such thick Smoak, that they darkned the Light of the Sun, and last of all pour'd forth such a storm of thick Ashes, that it cover'd all the Neighbouring Country like a high Snow, and which by the force of the Wind was carried over into Africa.

There is no question to be made, but that Fire is generated in the Earth, seeing that a vast quan∣tity of Brimstone and Jews-lime is contained in the same, which are of a very Fat substance above all others, and are most readily kindled: Neither do we find any matter within the Bowels of the Earth, is better suited for the production of Fire; and therefore we may well conclude, that what∣soever burns, or is hot, is preserved and maintained by the mixture of both these. And therefore no Fire breaks forth any where, neither doth any heat manifest it self, where both of these, or at least the one of them doth not bear sway. The Wind also may contribute not a little to the increase and dila∣tation of the Fire that lies hid in the Caverns of the Earth, whilst by entring into them, it doth more or less blow them up and kindle them, and makes the flame more violent.

IX VVhen Aetna first began to burn. When Fires first began to break forth from this Mountain, doth not appear from History: VIRGIL tells us, that in AENEAS his time, when in his Voyage to Italy he put in at Sicily, Mount Aetna poured forth Smoak and Cinders, with a horrid roaring Noise. And THUCY∣DIDES acquaints us, that this Mountain burnt in the 76th Olympiad, that is, 476 years before the Birth of Christ. And several times after that, as in the time of CALIGULA, &c.

X. VVhen the Mountain in the Isle of Java began to burn. In the Year 1580, a Mountain in the Isle of Java, not far from the City Panacura, began to burn, the top of it being burst open with a violent eruption of Brimstone, so that 10000 Per∣sons were consumed in the Country thereabouts, and cast forth vast great Stones upon the City Panacura. Moreover, for 3 days together it sent forth so much thick Smoak, mixt with Flames and Cinders, that it did cover the Sun, and almost turned the Day into Night.

XI. Of some Mountains that burnt formerly, and have now ceased. There are found some other Mountains, that now burn no longer. Thus in the Island Quei∣moda, not far from the Mouth of the River Rio de la Plata, there is a Mountain that burnt for∣merly, but hath now ceased. So likewise there are several Mountains in Congo and Angola, as also in the Azores, especially those of Tercera and St. Michael, which formerly cast forth flames, whereas now nothing but smoak proceeds from them; and this, because the Sulphurous and Bitu∣minous matter, which is the most proper to kindle and feed Fire, is quite consumed in them.

XII. Why these subterra∣neous Fires do com∣monly break forth at the Tops of Mountains. The Reason why these Subterranean flames, do generally get up to the tops of Mountains, and thence make their terrible Eruptions, is to be taken from the Nature of Fire, which being pent up in these Cavities, and not being able to dilate and spread it self, makes a breach in the Walls of its Prison upwards, rather than elsewhere, because there it finds less resistance, and being once broke forth, it continues burning as long as the fewel lasts.

XIII. Why the Fire doth not break forth from lower Grounds, as well as from Mountains. Subterraneous Fires seldom break forth from lower grounds; but very frequently from the Bowels of Mountains.

Of this, a twofold Reason may be given; First, Because Mountains contain many Cavities: And, 2dly, because those great fragments, whereof the outward Crust of the Earth doth consist, and which are so posited as to lean upon one another, do afford a more easie Egress to the flame, than the other parts. And tho' these Openings of the Earth, do close again, as soon as the flame is broke forth from them; yet there may be so great a quantity of Brimstone, and Bitumen or Jews-lime carried up from the Bowels towards the top of the Mountain, as may furnish sufficient Matter for a long continued burning. And as for those Steams which are afterwards gather'd again in these Cavities, and kindled, they easily afterwards make their way by the passage that is already open'd for them.

XIV. Why these Flames break forth from Mountains only at certain times and seasons. Burning Mountains, after some time cease to cast forth Flame and Smoak, and after this Cessa∣tion return to the same task again.

The Reason is, because that when the Sides of these Mountains are burst open, Water comes flowing in to the said Cavities, and stops up the Passages to them, so as that the Matter of Exha∣lations cannot so quickly be gather'd there again, and afford Matter to succeeding flames. It also very frequently happens, that by means of this vehement eruption of flames, the parts of the Mountain are overthrown, and fall down into the bottom of the Deep, from whence the fire did proceed; and the way for the Exhalations to break forth at, being thus stopt up, no further Burnings can be expected, till a fresh quantity of Brimstone and Jews-lime be gathered and kindled, which by its breaking forth may open those stopt Passages again, by casting up that which obstructed them. And this is the Reason why these Fire-vomiting-Mountains do not always retain the same Bigness: For Vesuvius, in Ancient Times, was of far greater bulk than now it is, and is scarcely an Italian Mile high, all its windings and turnings reckon'd in.

Nor will scorcht Aetna ever vomit Flame, Since from beginning 't did not do the same. Ovid. XV. Metamorph.

XV. Why upon an ap∣proaching Earth∣quake VVell-water be∣comes troubled. When an Earthquake is near, the Water of Wells becomes troubled and muddy, and sends forth a stinking smell.

This Effect is produced by the steam proceeding from the Subterraneous fire, which like a smoak breaking forth from a piece of Wood that is not throughly kindled, insinuates it self into the narrow pores of the Earth, and mingles it self with the said Well-waters. The said waters do likewise send forth a Noisom smell, because this steam, which ariseth from the Bowels of the Earth, pro∣ceeds from sulphureous and bituminous Bodies, wherewith the inward parts of the Earth do abound; which being of a strong and unpleasant smell, no wonder if their steams communicate a like odour to the waters.

CHAP. IX. Of Ashes and Coals.

I. VVhy Ashes are called Snow. AShes, or that light powder which remains after that the flame hath consumed all its fewel, in Combustible Bodies, are by Chymists com∣pared unto Snow, and they commonly call it the Snow of the Earth.

Because, as Snow doth consist of most small Drops, which by means of a subtil Vapour are woven or entangled together into flocks; so in Ashes, the smallest particles of the Earth, by a subtil interweaving of filaments, are joyned toge∣ther in lesser flocks, which may be discerned by the help of a Microscope.

II. How it comes to pass, that a Vessel full of Ashes, con∣tains al∣most as much wa∣ter, as ano∣ther Vessel of the same big∣ness that i•• Empty. Ashes soak up so much Water, that a Vessel fill'd with them doth very near contain as much Water, as another empty Vessel of the same big∣ness.

The Reason is, because the Pores that are inter∣cepted between the parts of the Ashes, are like so many flocks, that take in the Liquor poured upon them. And they are perceived to have little Bodies, like to cast Skins that suck in the water, and hide the same within their thin surfaces. But yet we must not from hence conclude with the Peripateticks, that there is the same quantity of water in a Vessel fill'd with Ashes, as there is in an empty one, seeing that the Ashes can scarcely imbibe a 5th part.

III. VVhy Ashes are of use for the cleansing of Linnen and VVoo∣len. Ashes are of great use for the scouting and washing clean of Bodies. And therefore those who take the spots of Oil, or any other greasy Matter out of Bodies, do make great use of Ashes, by means whereof they restore things to their for∣mer cleanness and neatness.

The Reason of this Effect is, because Bodies are made smooth by rubbing against one another, and lose all their Roughness: And therefore by the rubbing of Bodies with Ashes, all the dirt and the filth that sticks to them is washt away with ••elp of Water, which is that Vehicle, whereby the Ashes are carried into the most intimate retreats of the Body, where the filth or stains do lurk; for having some part both of fatness and sharp∣ness, they become entangled with them, and by rubbing fetch out whatsoever Unevenness remains in the Cloth. And thus by the mixture of Ashes and Water, a Lye is made, whilst the water being as it were strained through the pores of the Ashes, and taking along with it their sharpness and fat∣ness, it is made very efficacious for the washing and cleansing of things, from those stains and spots that stick to them.

IV. The Ashes of Fig-trees very proper for the washing out of Spots. Hence it is observed, that the Ashes of Fig-trees have a peculiar virtue for the Cleansing of Bodies from filth and stains; because the leaves and wood, whereof they consist, do abound with fat∣ness and sharpness, or acrimony, which entring into the inmost parts of Bodies, do carry the filth along with them. And it is for the same Reason, that these Ashes are found to be a good Remedy to stop the Fluxes of the Belly, and for the opening of Obstructions, making the Humors to run freely through the Body, and through the passages ap∣pointed for them.

V. Ashes pre∣serve the Roots of Plants from the cold. The Roots of Plants in Winter are covered with Ashes, to preserve them from being damaged by the cold, and that the melted Snow or Ice running down to them, may not hurt or injure them.

The Reason of this common use is, be••••use Ashes are dry, and almost destitute of all m••nner of Juke, and therefore drink up the melted Snow, and hide it within their Pores. For Ashes are not, and are agitated with intestine motions. For as Vinegar and the Lees of Wine, do retain a warm∣ing Virtue; so Ashes are partakers of a Fiery quality, and are endued with a Virtue, that resists the effects of cold.

VI. How Ashes contribute towards the mak∣ing of the Earth fruitful. And for the same Reason it is, that Ashes con∣duce to make the g••ound fruitful, because of the Salt that is in them. For the Fatness of the Earth is lodged in Salt and Nitre, which being resolved by moisture, and heated by the Sun, doth fer∣ment, and yields new productions. And there∣fore those Ashes whence the Salt hath been ex∣tracted, are of no use for this purpose, which may be prov••d by this Experiment: Dig a quan∣tity of Earth deep out of the Ground, and having divided it into•• parts expose them to the Air, the one in the same Condition as it came out of the Ground, and the other washt several times by pouring water upon it, and suffering the same to run through it▪ And you shall find, that this, latter▪ will produce nothing, whereas the other will bring forth Herbs, Worms and little Pebbles within some short time after.

VII. Why Coals are of a black co∣lour. Coals and all other adust things, as Soot and such like are of a black colour.

The Reason is, because there are more Pores in Coals, and also in the burnt parts of Animals and Vegetables, than there were in the same Subjects before the Fire had touched them, and which may be seen in Charcoal, by means of a Microscope. Now this multiplicity of Pores swallows up the Light, and hinders it from being reflected to the Eye. And from the multiplicity and largeness of these Pores, remaining in stead of the grosser mat∣ter, that hath been turned into Smoak and Steam, the Lightness of Charcoal doth proceed.

VIII. Why Coals keep Fire a great while. Coals do preserve Fire a good while, especially if they be covered with Ashes, and so kept from the Air coming to them.

The Reason is, because the Fire which lies hid in the Coals, is lodged in some thin and branchy Particles, which being intangled with others that are thicker, tho' they be most swiftly agitated, yet can only get out successively, that is, one after another. The Fire that is hid within the Pores of any Body, doth stand in need of some time, to have all its Particles dissolved, that by this means it may extricate it self from them; and probably before they can get thus free, the parts of the Coal must be worn and wasted by a long motion, and every one of them be subdivided into other parts again. But as long as the Air hath free access to Glowing Coals, they are much soon∣er consumed, because the Air doth by its motion blow away the Ashes, and entring into the Pores of the Coal, dilates them more than ordinary, and so makes way for the Fiery Particles to fly a∣way.

IX. How Wood is turned into Char∣coal, and how into Smoak and Ashes. Thus a piece of Wood being put into a Vessel and covered with Sand, within a short time after that Fire hath been put under the said Vessel, the Wood becomes turned into Charcoal, if so be the Vessel cover'd with Sand be not presently remo∣ved from the Fire, but so ordered that it may cool by degree••, not too suddainly lose all its heat. For if as soon as the Vessel is taken from the Fire, the Sand be removed, the Wood upon the letting in of the Air, will presently begin to Flame, and be wholly resolved into Ashes. Because the Branchy particles of the Wood, become by ••his means se∣p••rated from each other, and upon the removing of that which hindred, are dissipated in the Air.

X. A Live Coal being sprinkled with wa∣ter, grows the hotter. If a little water be sprinkled upon a ••ive Coal, the heat is thereby encreased.

Because the moisture by entring into the Pores of the k••ndled Body, doth drive the Particles of the Fire into the inmost parts of it, and becomes mingled with them, but being forced to return by reason of the predominating heat, it carries the Particles of Fire, which lay hid in the Pores along with it, to the extream parts of the Body. And the same is the reason, why water which extin∣guisheth small Fires, yet by the fatness which it contains doth make great Fires burn more fiercely, because by the motion of its flexible parts, it car∣ries forth the heat, and raiseth the flame to a great∣er height.

XI. Why Char∣coal enters the compo∣sition of Gunpowder. In the making of Gunpowder, Charcoal-dust is mixed with Brimstone and Nitre, and being moist∣ned with some Liquor, this Composition is for∣med into small Grains, which of all other matter do most readily kindle and take Fire.

The Reason why Charcoal-dust is made an in∣gredient of Gunpowder is, because it abounds with Pores, and therefore is most easily penetrable▪ And no wonder that Charcoal is very porous, seeing that before the Fire had wrought upon it, the Wood it self had many little passages, which after∣wards by the operation of the Fire, and the eva∣poration of so many Particles in Smoak and Steam, were mnch encreased: To which may be added, that Charcoal chiefly consists of 2 kind of parts, whereof the one are Thin and Branchy, which as soon as they come near the Fire are easily kindled; as having already been agitated by the force of the Fire, but yet continuing entangled together by their slender and manifold Branches, which al∣so would have made their escape, if the quenching of the Fire, had not stopt their flight. The other parts contained in Charcoal are thicker, which if the Fire had acted longer upon them, would have been turned into Ashes. So that in this Composi∣tion of Gunpowder, the Branchy Particles of the Brimstone, and the sharp Needles of the Nitre, penetrating into the large Pores of the Charcoal, become entangled with its Branchy parts and close∣ly drawn together, especially by that time they are dried, after that the whole mixture, by the addition of some moisture, hath been formed into small Grains. This composition becomes kindled in this manner; First, the Fire being applied, immediately kindles the Brimstone, and at the same time puts the Par∣ticles of Nitre into motion, which thereupon re∣quiring a greater space wherein to take their turns, do rend the Bands of the Charcoal, and resolve the Grain into Flame and Smoak. For the resistenee of the Charcoal doth greatly promote that swift∣ness, whereby the whirled Needles of the Nitre do break forth into a suddain Flame.

XII. Why Ashes are white. Ashes are commonly of a whitish colour, which grows much darker when water is cast upon them,

Ashes are white, because the Particles which constitute them, are Sph••••rical, which our Touch can convince us of, for asmuch as ••hey feel smooth without any roughness at all. And consequently reflecting the ligh•• on all sides, they exhibit a white colo••••; which becomes darker upon the affusion of water, because, moisture, as ha•• been said, promotes blackn••ss.

XIII. How Wheat comes to grow from the Ashes of it. Credible Authors answer us, that Wheat hath sprung from the Ashes of it Sown in the Gound.

The Reason is, because the Salt which remains in the Ashes is a solid substance, and contains a great portion of Earth, and consequently is most proper for the generation of Plants, since it can∣not easily be exhaled, and becomes resolved by the force of Heat. Wherefore these rudiments of the Plants remaining in the Ashes, being dissolved by some convenient moisture, and the warmth of the Air, spring forth into a new Plant. Thus Hogs∣dung produceth Sowthistles, and that because it is common for those Animals, to feed upon them; for the Seed of Sowthistles remaining in the Dung, and resolved by heat and moisture, pro∣duce other Plants of the same nature.

XIV. The Ashes of a Plant contain the princi∣ples of a new Plant. Hence it is that if we put the Ashes of any Plant into a Vessel with water, and expose the same to the Air in the Winter-time, as soon as the water is frozen, the resemblance of the Plant will be exprest on the Ice, at least the Leaves of it. Which is a pregnant Argument, that in the Ashes there remains a Principle of a new Life.

CHAP. X. Of Glass.

I. What Ashes are most proper for the mak∣ing of Glass. THE most proper Ashes that are known, for the making of Glass, are those of the Herb Kali, and Fern.

Tho' the parts of Ashes be very gross and irre∣gular, and cannot, tho' they lean one upon ano∣ther, so unite together, as to compose a hard Body, because the Air which fills the Pores that are left between them, doth hinder their Rest; yet the Ashes of the Herb Kali and Fern, are therefore the most proper of all others for the making of Glass, because they abound with abundance of fixt Salts, which are very porous and spungy; so that when these Ashes are put into a violent Fire, their corners are consumed by it, and by this means the surface of their parts is made so smooth and even, that they touch in more Points than they did before, and afford a free passage to the Beams of Light, and cannot be rendred dark or opake without the mixture of some Forrein Matter.

II. Why Glass is Transpa∣rent. Glass notwithstanding that it is a hard Body, and made up of the thick and irregular Particles of A∣shes, yet doth constitute Transparent and Light∣some Body.

The cause of this perspicuity of Glass, may be easily gathered from the make of it. For whilst the matter of it, was by the violence of the Fire reduced to a liquid form, and all its Particles in agitation, the Fire flowing round about them, hol∣lowed many Cavities in them, which the 2d Ele∣ment freely entring, diffused the action of Light to all parts, in right Line••. And forasmuch as the said Pords, are after the Glass is made 〈◊◊〉〈◊◊〉 preserved and kept open, by th•• i••cessan•• passage of the subtil matter, and are filled as be∣fore, they cannot but transmit the L••ght as fore∣merly, so that the same transparency which was in the molten and liquid Glass, remains in the cold and hardned. For this i•• a thing common to all Bodies that are melted in the Fired that whilst they are yet in that liquid form their parts do easily accommodate themselves to any Figure, which they retain after that they are grown cold▪ If at any time any darkness be perceived in Gl••ss, that proceeds from some Dr••g•••• Clouds or Bubbles that are mingled in its texture, which since they are much more numerous in thick Glass than 〈◊〉〈◊〉 thin, therefore we must inpute the darkness of thick Glass to them.

III Why Glass is Brittle. Glass is very Brittle, and will not suffer it self to be extended, but upon the least stroak breaks to shivers,

The Reason is, because tho' Glass be a hard Body, and does consist of parts that are thick e∣nough, yet forasmuch as the surfaces by which they touch one another, are very small, so that they joyn only in Points, for this reason it ••s, that if they be never so little separated from each other, they lose their union and fly into bits. Whereas many soft Bodies are much harder to be broken, because they have their parts so intangled, that they cannot be separated, without the breaking of many of those Branches, by which they were held together.

IV. Glass some∣times breaks of it self. It is a thing known by long experience, that Glasses after they have lasted a long time, do at last break of themselves. More particularly this is notorious to them, who grind those Glasses that are used in Prospective Glasses; for they find that after they have been polished a long time, they slit of themselves. The cause whereof is, because the Saline Particles, being agitated by the subtil Matter, do endeavour to break loose: As may be gathered from hence, that in the Winter season, and Rainy weather, something may be wiped from Glasses, that hath a Saltish taste. And not long since there was a certain man at Amsterdam, who broke Rhenish-wine Glasses only with his Voice, and that not very strong neither, but tuned to a certain Pitch.

V. Why Glass that is newly taken out of the Furnace doth break when ex∣posed to the Air. A Glass newly taken out of the Furnace, if it be exposed to the cold Air breaks immediately; and so likewise if any water be cast upon it.

The Reason is, because when the cold doth draw together and narrow the Pores of the Glass, the subtil Matter and the fiery Particle•• are by this means lockt up in them: And whilst the former of these press to make their way through the Pores of the Glass, and the others endeavour to get out from it, they by striving to widen the Pores, make the Glass to fly in pieces.

VI. A cold Glass ••eld to ne•••• the Fire cracks If a cold Glass be held so near to the Fire, that it heat in one part more than in another, it present∣ly breaks.

The Reason is, because when the Fire is got in to the Glass, the Pores of it are not all equally dilated by it, and therefore when the subtil matter gets into them, seeing the Pores where the Glass is cold, are not wide enough for its free passage, it makes way for it self by rending the Glass to

pi••ce••▪ But if it be by degrees, and by little and little held b•• the fire▪ it will suffer no hurt at all; b••cause all 〈◊〉〈◊〉 po••••s will by this means be suffici∣en••ly 〈◊〉〈◊〉 so as to afford a free and open passage for the subtil matter. And therefore when Glas∣ses that have contained any hot Liquor, are suddain∣ly ••mptied and exposed to the Air, they crack immediately; because the subtil matter, which is pent up in the pores of Glass Vessels, striving to get out, finds no way for it self, because the pores are constringed by the coldness of the Air; and therefore makes its way by breaking the 〈◊〉〈◊〉 sides of the Glass.

VII. How the breaking of Glasses may be prevent∣ed. To avoid this breaking of Glasses, they that belong to the Glass houses▪ take the Glasses that are newly blown, and set them in a place at some distance from the fire to Neal, as they call it, removing them every 6 hours, the distance of 8 or 10 Foot, before they expose them to the Air; by which means all the parts of the Glass being insensibly and equally cool'd, there is an equal constriction of the Pores, so as that the sub∣til matter which can pass one of them, can with like ease pass all the rest.

VIII. How Glass comes to have an Attractive Virtue. Glass seems to have something of a Magnetick Virtue; for when it is strongly rubb'd, so as to be heated thereby, it draws the neighbouring Bodies to it self.

The Reason is, because the agitated particles of the 1st Element, continually pass from the Glass into the Air, and others from the Air return to the Glass, to take up the room of the former; and because those particles which return from the Air, have not all of them the same degree of Agitation, those which have less, are driven towards the little slits; which have no correspondent Pores in the Air, and being, as it were, heaped upon one ano∣ther, do constitute certain wreaths, which in pro∣cess of time acquire determinate Figures, which afterwards are not easily changed. Wherefore when Glass is strongly rubb'd, so as to grow hot, these wreathed particles being driven out, are dif∣fused indeed through the neighbouring Air, and enter into the pores of Bodies that are about them: But forasmuch as they do not there find an open and ready way for themselves, they return to the Glass immediately, and carry along with them any little Bodies they meet with in their way.

IX. Glass be∣comes va∣riously co∣loured, by being ming∣led with Metals. When in the melting of Glass, a Metal is mix'd with it, the parts whereof cannot so easily be smoothed and polished by the action of the Fire, as those of the Ashes are whereof the Glass is made, then the Glass becomes ting'd of divers Colours.

The Reason is, because the metalline particles, which are very irregular, do insinuate themselves into the pores of the Glass; and by this means, make the parts of the 2d Element, that pass through the same, to move and roll differently from what they did before, and consequently to represent those Colours which are caused by these their diffe∣rent rolings.

X. What is the reason of the stif∣ness of Glass. Glass is very stiff, and cannot be bent without the danger of Breaking. Wherefore, if it be ne∣ver so little bended one way, it presently springs back like a Bow, and returns to its former Figure.

The Reason is, because this bending doth some¦what change the figure of the Glass, and straitens the pores of it; so that the particles of the 1st E∣lement, that before past through them, finding then way not so easie as before, and yet pursuing their motion as far as they are able, force the sides of them, and endeavour to reduce them to their former figure. For this property of leaping back, is not peculiar to Glass only, but to all hard Bodies, whose particles are joined by immediate contact, and not by the weaving or intangling of Branchy parts. As is evident in a bended Bow of Steel or Wood, which presently leaps back to its former state, except it have continued bent too long▪ and that the subtil matter hath found or made it self other passages to run through▪

XI. Why Glass melts by the force of Fire. Glass is melted by the action of fire, and whilst 〈…〉〈…〉 so, is easily formed into all sorts of figures.

The Reason is, because the parts of Glass having been before worn and polished by the force of fire, are easily moved, and obliquely creeping, and flowing one upon another, they begin to touch each other in some small part of their surfaces, and following one another, constitute a fluid Body, which may be formed into any figures, according to the pleasure of the Artist. Moreover this fluid Body, as it grows Cold, becomes tough like Bird∣lime, so as that it may be drawn into thin Threds; because as long as that motion is continued in it, whereby its parts do flow; lying obliquely upon one another, it may the more easily be drawn out into Threds, than it can be broken.

XII. Glass bea∣ten to Pow∣der becomes a Poison. Glass beaten into Powder, according to the opi∣nion of some Physicians, becomes Poison.

The Reason of this, as I suppose, may be, be∣cause the pieces of Glass are hard and sharp, which hurting and wounding the Membrans of the Sto∣mach and Guts, as well as of the other smaller vessels, become destructive to the Body of Man. For I do take Glass, when it is yet whole, to be no Poison at all; forasmuch as many have swal∣lowed it without any hurt; which is an argument, that all the hurt that can accrue to our Bodies from Glass, must proceed from the hardness and figure of its little particles.

CHAP. XI. Of the Air.

I. Why the Air is in∣sipid. THE Air is insipid, and makes no impressi∣on on of Taste upon the Tongue.

The Reason is, because it swims upon our Spit∣tle, and doth not mingle with it, and therefore cannot affect the Nerves of the Tongue. And hence also we may see the reason why water is in∣sipid; as likewise why fat Liquors are less discerni∣ble by their taste, than dry things.

II Why the Air that is nearer to the Earth, is hotter than that which is further off. The Region of the Air, which is nearest to the Earth, is found to be warmer than that above it, where Cold hath a greater dominion, and where Hail, Snow, and other cold Bodies are ge∣nerated.

The Reason is, because the Rays of the Sun be∣ing copiously reflected from the Earth, do agitate the parts of it more than ordinary. For a violent agitation of the parts of the Earth produceth Heat, especially if it be caused by the Light, and do con∣tinue for some time. And forasmuch as the Rays that are reflected from the Earth, are not in so great abundance carried up to the higher Regions

[illustration]

[illustration]

Book. 2. Part. 4. Chap. 11.

G. Freman. In.

〈◊〉〈◊〉 K••p 〈◊〉〈◊〉

of the Air; and those which get up thither, do communicate their motion all along to the Bodies they meet with, it cannot be, but that cold must succeed upon this diminished agitation, and so give occasion to the condensation of Clouds, and the production of Snow and Rain.

III. How the Air may be made more heavy. The Air being thrust and crouded into any vessel, does become more heavy, than that which is diffused in a free and open place. Which GA∣LILAEUS made an Experiment of after this manner. I took, saith he, a large Glass Bottle, and carefully applied to the Mouth of it the Neck of a Bagpipe, by which means I crouded into it a very great quantity of Air; for because of its easie condensation, 2 or 3 Bottles full of Air were thrust into it over and above that which was in it at first. Now by this Experiment Galilaeus learnt, that the crouded Air had made the Bottle more heavy than before; and that as soon as the Mouth was unstopt again, the weight of it was again di∣minished.

The Reason is clear and evident; because in the condensation of Bodies, the parts come nearer to∣gether and are more intimately joyned; And there∣fore being in greater quantity, they cannot but weigh more than before; for a greater quantity of Air makes the Vessel more heavy than a less quantity. As will be evident, if this Bottle with Air be fitted to another Bottle full of Water, with a hole at the bottom of it, which may be opened at pleasure: For when the Bottles are thus joined together, and a passage left open for the Air to enter into the Bottle full of Water, as much Wa∣ter will run out as there was of condensed Air that was crouded into the other Bottle. And there∣fore we are to suppose, that the quantity of Air, that was with force driven into the Bottle, is equal to the quantity of Water, that was driven out from it through the Bottle.

IV. How much the Water is Heavier than the Air. It seems to be difficult to determine how much the Water is heavier than the Air; forasmuch as the weight of the Air is not the same in all places. Yet may the same be, in some sort, determined from a late Experiment; by which, well-nigh, all the Air having been contracted out of the great Glass Vessel of the Pneumatick Engin, and the Mouth of it stopt, it was laid in a Scale, to know exactly how much the Vessel weighed without Air; and afterwards when the Air was let in again, it was weighed a 2d time, and then found that the Vessel weighed about an ounce and half more than it did before: So that according to this Experi∣ment the Water should seem to be almost 1000 times heavier than the Air.

V. A Descri∣ption of the Pneuma∣tick Engin. For the further clearing of this, and the follow∣ing Phaenomena, I think it will not be useless to give here a description of the foresaid Engin or Machin. It consists chiefly of 2 parts, viz. of a Syringe or Pump, and a Glass Vessel, which is called a Recipient, whence the Air is pumped. Be∣tween the Syringe and the Recipient is a Copper Pipe, through which the Air passeth out of the Recipient into the Syringe; and in the Pipe is a Peg, by the turning of which the Air is either suffered to pass out of the Glass into the Syringe, or stopt from passing. When therefore the Sucker is pulled up, the lower part of the Syringe is stopt with ones Finger, that the Air may pass out of the Recipient into the Syringe; and when the Sucker is prest down, then by turning of the Peg the Air is hindred from passing out of the Reci∣pient into the Pump; and by removing ones Finger, the Air is driven out of the lower end of the Sy∣ringe; the rest will be easily perceived by the Eye, or understood from the Figure. A is the Pump, at * 1.6the bottom whereof B is a little hole, which is shut with ones Finger, when the Sucker is drawn up▪ by means of the Handle belonging to the indented Wheel, and of a plate of Iron also indented, which is fastned to the Sucker. When the Sucker is drawn up, the Air rusheth forth out of the Reci∣pient F, through the Pipe I, into the Pump: For then by turning the Peg L, the Air hath an open passage afforded it into the Syringe; but when the Sucker is thrust downwards, and the Peg turned the contrary way, the Air is stopt from returning into the Recipient; and then upon taking away ones Finger B, the Air is thrust out through B, and the Recipient, by degrees, is emptied: And this pumping must be reiterated so long, until the Recipient F be emptied of all the Air that was in it. Having thus set down the Frame of this En∣gine, we will proceed to some Experiments that are made by it.

VI. According as the Air i•• ••ither exhausted or let in, so the Stopple of it is ei∣ther more hardly, or more easily removed. 1st. After that the greatest part of the Air, contain∣ed in this Engin, is evacuated, the Stopple which shuts the upper Mouth of it, cannot without diffi∣culty be removed, as being prest down with a greater weight; but is most easily removed, when by turning of the Peg the Air is let in again; for when that Hole is shut, the outward Air doth more strongly press the Engin, than when it is open.

VII. The same effect hap∣pens to the Plug. 2dly. Upon the same Evacuation, the Sucker is very difficultly drawn upwards; but being drawn up, doth of it self run down again, tho' an 100 pound weight were fastned to it; because upon the exhausting of the shut up Air, which before bal∣lanced the outward Air, this being now become more heavy, forceth the Sucker to enter into the Pneumatick Pipe, so as that being, as it were, bound with strong Bonds, it cannot be separated.

VIII. A Square Glass Bot∣tle breaks upon the evacuation of the Air. 3dly. A Square Glass Bottle, tho' it be of thick Glass, upon the evacuation of the Air, breaks immediately; whereas a round Glass, tho' it have a crack in it already, doth not only not break, but also keeps the external Air from entring into it; because, by how much the External Air doth more press the parts of the Glass, the more they do mutually support each other, as we see it is in arched Roofs, so that none of them can give way: But the case is different in a Square Bottle, which hath much less force to resist, as being unable to withdraw the force and weight of the External Air.

IX. A Bladder, upon the evacuation of the Air, swells in the Pneu∣mati••k En∣gin. Hence it is, that if you tie the neck of a Blad∣der, after that you have squeezed the Air out of it, and so put it into the Glass Recipient, upon the Evacuation of the Air, that was in the Recipient, you will find the Bladder begin to swell, and to that degree, that sometimes it bursts, with a great noise. The same thing may be seen in the com∣mon Torricellian Experiment: For if you put the Bladder of a Carp, almost void of Air, into the Pipe, it is presently blown up, because the remain∣ing parts of the Air, being loosened by the neigh∣bouring Air in the Pipe do extricate themselves. And therefore as soon as the Air is let in again into the Recipient, or into the Pipe, the swoln Bladder

immediately falls again. The same thing also hap∣pens when the parts of the Air are agitated by Heat; for we see that a Bladder, which is not above half full of Air, if it be laid near the Fire, is blown up to the utmost, and becomes very hard.

X. Aqua For∣tis and Vi∣negar do swell in the Pneuma∣tick Engin. Aqua Fortis, in which a Metal hath been dissol∣ved, and Vinegar impregnated with the solution of Coral, do wonderfully swell in the Recipient, upon the extraction of the Air, and seem to boil; be∣cause the Particles of the Air, that are shut up in the pores of these Liquors, being set at liberty by the pression of the Ambient Air, do diffuse them∣selves into a larger space. And so likewise it hath been observed, that i•• a shrivel'd Apple, be put into the Recipient, after that the Air is drawn out, it becomes plump up again, and looks as fresh, as if it had been but newly pluck'd from the Tree; and if the Skin of it be broke, a kind of a froth breaks forth from it, as if it were roasted at the Fire.

XI. How Bullets are dis∣charged from Wind-Guns by the compression of 〈◊〉〈◊〉 Air. The Air when shut up in any Vessel, and com∣prest by outward force, becomes endowed with a power to leap back or rebound, as is evident in Wind Guns, from which leaden Bullets are dis∣charged with so great force, as they seem to ex∣ceed the force of those that are discharged by Gun∣powder. So likewise there are many other Engins, which by compressing of the Air only, cast up waters to a great height.

The Reason is, for that when the Air is com∣prest within these Pipes or Engins, every one of its particles cannot enjoy that round space it stands in need of, to turn round about its own Center; but other neighbouring particles encroach upon it. And seeing that the same force of heat, or the same agitation of the said Particles, is preserved by the motion of the Heavenly Globuli, and that they cannot freely display themselves, being hindred by their neighbours pressing in upon them, they hit and push one another with their Corners, driving each other out of their places. And thus with uni∣ted forces strive to recover their former liberty, and a larger space to move in.

XII. What is the reason of the sud∣dain and violent eruption of fermented Liquors out of the Bot∣tles, where∣in they have been pent up. In like manner small Wines, and new Beer or Ale, being put up into Bottles, break forth, as soon as they are opened with a great force; because the parts of the Tartar or Wine-Lees, being pent up within the sides of the Bottles, cannot be separated, or flee from one another; and therefore by means of their intestine agitation, do so cut and divide one another, that tho' they be mixed, yet there is no connexion between them; which is the Cause, that as soon as the Bottle is unstop'd, they break forth with great noise and violence, in the form of froth.

XIII. Why a Blader that is blown up▪ being struck against the ground▪ doth rebound again. Thus also blown up Bladders, being struck a∣gainst the Ground, do rebound again: for the Air being comprest in the Bladder, is agitated by the subtil matter, which is lodg'd between the parts of it; and striving to recover its former freedom, lifts up the Bladder; and being unable to bear any greater▪ compression, beats back the hard Bodies it meets with. The same Elastick Force is clearly demonstrated, by putting a Swines Bladder, di∣stended with Air, into the Pneumatick Engin; which upon the evacuation the Air, doth ordina∣rily distend it self to bursting: Sometimes lifts up 50 pound weight, because the shut up Air being delivered from the weight of the External Air, doth endeavour a greater dilatation, and by extri∣cating it self, takes up a greater place.

XIV. Why the water is prest▪ ••••wn∣ward 〈◊〉〈◊〉 •• Weather-Glass, in hot wea∣ther. Accordingly also a reason may be given of the descent of the water in a Weather-glass, when it is hot: For the Air that is contained in the Glass, being agitated by stronger Beams of the Sun, or with more Heavenly Matter, doth dilate it self, and consequently bears down the water; which cause is no sooner removed, and the dilatation diminished, but the water riseth again as be∣fore.

XV. How it comes to pass, that a weak brittle Glass can resist this Ela∣stick force of the Air. But you'l say, if the Air▪ be endued with an Elastick Force, how comes it to pass, that when it is shut up in thin Glass Bubbles or Drops, Herme∣tically Sealed, it doth▪ not break through the thin Walls of its Prison?

I Answer, that these weak Bubbles are not bro∣ken; because as the Glass is prest by the inward Air, so in like manner the outward Air dasheth against the said Glass, and because the force is on both sides equal, it cannot break the Glass. For the same reason it is, that Bubbles swimming on the water, continue whole for a considerable time without breaking; and so making way for the pent up Air to get out. Which could never be, without the pression of the Ambient Air; foras∣much as the Air, by its Elastick Force, is able to break very thick Glass to pieces.

XVI. How the Heaviness of the Air may be proved. Take a Glass Pipe 3 foot long, having one end of it stopt up, and the other open, and fill it with Quicksilver to the top, then turn it with the open end of it downwards into a Vessel like∣wise full of Quicksilver, so that it may run down into the Vessel. And you will find that the Quick∣silver will not descend to the Bottom of the Pipe, but will continue 27 Fingers breadths high, or thereabouts.

The weight of the Air is the cause which keeps the Quicksilver at the height, and doth not suffer it to sink lower. For tho' the Quicksilver that is in the Pipe be very heavy, yet can it not run down into the Vessel that lies under it, without raising the Quicksilver that is in it, and conse∣quently the whole Mass of the Air that lies above it. Now the thick and agitated parts of the Air, do hinder its further condensation, because it is not without reluctance that they suffer any compression, and are reduced to a more narrow space and compass. But yet we must not imagine that every Air hath a like force to resist, but that the same varies according to the degrees of its Rarity or Density, that is, its looseness or compact∣ness: For a loose and thin Air, and whose parts are more weakly dilated by Heat, is more easily bent, and doth less resist the pressure of the Quicksilver, than that Air which is more thick, and the Particles whereof are more vehemently expanded. And for this reason it is that the Quicksilver sinks lower in Fair, than in Cloudy and Rainy Weather, and that the Air which is on the top of Mountains, doth less oppose the driving of the Quicksilver, than in a Valley or shady place; because in this latter place the Air is thicker, and more weakly agitated by the heat of the Sun. Wherefore it is evident that the Quicksilver contained in the Pipe, is kept up by the weight of the Air, and that it would sink till it came to be level with that which is in

the Vessel, in case it were not hindred by the weight of the Air that lies upon it.

XVII. The Quick∣silver in a Weather-Glass is variously raised, according to the Change of th•• weather. Thus we experience, that when the North∣wind blows, and it is Fair-weather, the Quick∣silver riseth higher, and sometimes to 28 fingers breadths; whereas when the South-wind blows, and in Rainy-weather, the Air is much lighter, and the Quicksilver only riseth to 27 fingers breadths. Thus also by the means of Pumps, the higher that the Quicksilver is in the Bar••metrum, or Instru∣ment to distinguish the weight of thing••, the higher the water riseth, that is, 32 fo•••• high, when the North-wind blows; but during a South or West-wind, and in Rainy▪weather, scarcely 31 foot high, and so much the less as the Pump is placed on higher ground.

XVIII. The Con∣tact or Connexion of Bodies is caused by the Heaviness of the Air. The mutual contact of Bodies, whence they derive their firmness and connexion, is a pregnant Evidence of the weight of the Air: For we find, that 2 Marble Polisht Bodies, besmear'd with Oil, do sometimes so closely stick together, that a closer Connexion can scarcely be apprehended. But no sooner are these 2 Bodies put into the Pneumatick Engin, but immediately, upon the evacuation of the Air, the piece of Marble that lies undermost, is immediately separated from the upper; because the Air, that lies under the Lower Marble, doth no longer bear it up, and is no longer able to keep it close joyned with the upper.

XIX. How it comes to pass, that sometimes 2 Marbles stick close together in a place that is void of Air. And if at any time it happen, that 2 Marbles stick close together in a vacuum, the Cause is only this, because the subtil Air, which pierceth through the sides of the Glass, doth not find any entrance between 2 exactly polisht Marbles: And therefore the lower Marble cannot fall down without pres∣sing and raising the foresaid Substance, which resists more than it can be pressed by the Body that lies upon it. But when Marbles are anointed with Oil or Spirit of Wine, that by means thereof they may be the more closely glewed together, then, as soon as the Thicker part of the Air is drawn out of the Recipient, Aiery Bubbles do im∣mediately arise from the said Oil and Spirit; which Bubbles being afterwards dilated by the Elastick virtue of the Aethereal substance, do separate the Marbles, that before stuck toge∣ther.

XX. Why a Bladder fill'd with Air doth sink the slower, the nearer it comes to the bot∣tom of the Water. Hence we may conclude, that a Bladder fill'd with Air requires the greater force to press it downwards, by how much the nearer it comes to the bottom of the Water; because the Air riseth the more slowly from the bottom of the Water, towards the Region of the Air, by much the nearer it approacheth to it. And the Reason is, because fewer parts of Water do lye upon it, which by lifting up the Bladder or Air from be∣neath, push it upwards. Wherefore, if we should suppose the Flame to mount up through the Air, quite to the Orb of the Moon, it would still move slower and slower, the higher it ascended; because the fire doth not mount upwards by any virtue of its own, but is only driven upwards by the Air that surrounds it. For the Parts of the Air that are nearer to the Earth, being more comprest by those that lye upon them, they do with more force push forwards the flame, than when they are more remote from the Earth; where, because they have fewer parts pressing them downwards, they lye the looser, and consequently drive up the flame more faintly.

XXI. By what means the Quick∣silver is hindred from sink∣ing lower in the Glass-Pipe. If a Glass-Pipe that is not 27 fingers▪ breadth long, after the manner as before explained, be filled with Quicksilver, it will not at all sink down in it; but will continue fill'd in the top, without any subsidence.

The Reason is, because the particles of the External Air are so agitated, and do so comply with the motions of the Heavenly Globuli, that they cannot be comprest by the weight of the Quicksilver, that is, less than 27 fingers breadths high, and consequently do so dull its force▪ 〈◊〉〈◊〉 to hinder its descent.

XXII. Why the Water in Pump•• cannot rise above 31 Foot high. The Water is raised in Pump•• by the motion of the Sucker; but cannot be raised above 31 foot high.

The Water mounts up, together with the Suc∣ker, when it is drawn upwards; because there is no Vacuum in Nature, and all Spaces are fill'd with Bodies, so that there can be in motion, without a total Circulation of the Bodies, that are about the thing which is moved. And therefore it happens, that as soon as the Sucker is drawn up, it makes the Air that was above the Pump, to move about the midst of it; and that which was about the midst ••f i••, to come into the place where the water is, which ••••unting upwards comes in the room of the Sucker. For the Water chiefly moves that way, where is ••he least pressure of Air, that is within the Bore of the Pump, which the Sucker hath left. Now the Reason why the water, by means of Pump••, cannot ascend above 31 foot, is, because the Air, by its natural weight, having driven up the water without condensation, and being afterwards unable to bear a greater weight of water, is by the motion of the Sucker shaken with greater violence than ordinary, and by this means plyes and is broken; and because the subtil matter is driven out above the water in the Bore of the Pump, the water settles at the due height of 31 foot.

XXIII. How Suck∣ing is performed. And it is for the same Reason that the water mounts up in a Pipe, upon the sucking of it; for the Air by its weight presseth all the parts of the Water, or other Liquor that is in the Vessel, in which one end of the Quill or Pipe is dipt, ex∣cept only those parts which are directly under the Lower-end of the Quill, which is opposite to the upper part of it, which is in the Mouth of him that sucks: Whereupon, as soon as the Muscles have lifted up the Palat and the Breast, the Air within dilates it self, and being dilated, is not of strength enough to hinder the water from entring the Pipe, into which the external Air drives it; whence it is, that when we suck through a Pipe of a certain length, it is all one as if the Mouth it self were extended so far. And it is by the same Reason, that an Infant, by applying his Mouth round the Nipple of his Mothers Breast, draws the Milk from it.

XXIV. Why a mans Hand stretched out in the Air, doth not per∣ceive any weight. A Hand held forth in the midst of the Air, feels no Heaviness; tho' indeed the Air it self be Heavy, and consequently must needs press the Hand.

The Reason is, because the Hand is prest on every side by the ambient Air, and as much by that which is under it, as by that which lies upon it. For the Air which is under the Hand, is driven

by the weight of the other parts of the Air that are on the sides of it. Like as the water which answers to the bottom of a fraighted Ship, is dri∣ven towards the bottom of the Ship, by the weight of the water that surrounds it at the top. Seeing therefore that the upper Pillar of the Air hath no more Power to drive the Hand downwards, than the lower hath to drive it upwards; it is no won¦der that we are not sensible of any weight, when we reach our Hand out into the Air. Hence it is also, that when we lay our Hand upon the Mouth of a Vessel, whence the Air is extracted, it begins to swell.

XXV. VVhy a Glass Vial breaks, when put into the Recipient of the Pneuma∣tick Engin, after that the Air is exhausted. And the same Reason must be given why a Glass Vi••l being put into the Recipient of the Pneumatick Engin, after that the Air is pumped out of it, breaks to pieces; for seeing that there is no outward Air that might repel the force of the inward, and resist the force of its endeavour∣ing to dilate it self, the Air which is within the Viol, bearing against the sides of the Recipient, hath the power to press and draw i•• together, and at last to break it to pieces.

XXVI. VVhy the flesh swells upon the application of Cupping-Glasses. And for the same Reason it is, that when the Air is dilated by the Flame in Cupping Glasses that Chyrurgeons make use of, as soon as the Fire is extinguish'd, the Flesh that is contain'd within the Cupping Glass, begins presently to swell; because that part is less prest upon by the rarefied Air, than that which bears the weight of the outward Air. And this makes it appear, that the Sucker in the Pneumatick Engin, after that the Air hath been exhausted out of the Sy∣ringe, the under Orifice whereof is stopt, cannot be drawn up because of the weight of the Air. For the Pillar of Air which is of the same Bulk with the Sucker, must first be removed out of its place. But when this outward Air is extracted, then the Sucker is without any trouble at all drawn out of the Syringe, tho' the lower Orifice be stopt.

XXVII. VVhy the water that is in a Glass, doth sometimes appear lower i•• the midst, and some∣times higher. The same Reason also must be assigned why water, that is in a Glass or Cup that is not filled to the brim, seems to be low in the midst, and more raised towards the Edge, as hath been already mentioned; for the middle part of the water is prest on every side, but not the extream or out∣side parts, upon which the Air exerts its force more weakly and obliquely. But on the contra∣ry, when the Glass is fill'd to the top, the water swells in the midst. For besides that the water cleaves close to the sides of Glass, its middle parts are only comprest by the Air that lies above it, whereas the outsides are prest every way; and the Air that lies under it, and i•• beneath the Ho∣rizontal Line, exerts its force upon that part of the water which toucheth the sides of the Glass; which makes the water strive to get thither, where the pressure is weakest.

XXVIII. VVhy the Air grows lighter up∣on the ap∣proach of Stormy VVeather. Before a Shower or Storm, the Air is not so heavy as it was before; and the same is when the South-wind blows, tho' no Shower follow.

The Reason of this seems to be, because the Steams or Vapours which arise out of the Earth, and which mingle themselves with the Particles of the Air, are precipitated, and condensed into Clouds: By which means the upper part of the Air becomes much dilated, and quitting those Bodies that mixed with it, becomes more thin and subtil. For there is no question to be made, but that the Air contains in it self many parts of wa∣ter, from the Coagulation and Condensation where∣of Clouds and Showers are formed. This appears in Mr. BOYLES Pneumatick Engin; for as soon as the Air enters the void Recipient, it appears, as if it were all covered with a Mist.

Notes

• * 1.1

  Figure 18.
• * 1.2

  IV. Why Spring Water is fresh.
• * 1.3

  III. The Red-Sea is not higher than the Mediter∣ranean.
• * 1.4

  Figure 46▪ in the In∣stitution.
• * 1.5

  Figure 19.
• * 1.6

  Figure 20.