by the fuperincumbent Water, it is forced to give way, and finding no place to flow to, it retires towards the Sides, and pervades the Foundations of the Mountains; where being collected, as in a Ciftern, it is ftill urged forwards towards the tops of the Mountains by the incumbent Water of the Ocean. As we may observe in a Tankard that has a Pipe on the fide (reaching to the very bottom) made to pour Wine thro' into Glaffes; if, I fay, we drop a Stone into fuch a Veffel, whether it be full or half full of Liquors it will fpout out at the Orifice of the Pipe. This is Scaliger's Subtility, but it is too grofs to pafs. For the Water is not thus forced towards the tops of the Mountains, fince Experience fhews us the contrary in Mines; and if it were fo, the Water of all Springs would be falt; befides, it is falfe to fay that the Water is not in it's natural Place, and therefore preffes upon the Water underneath, for this is affumed without Proof, and is contrary to Experience. Water does not prefs upon the Parts below, unless it's Surface be of an unequal Altitude, but the Surface of the Ocean is fpherical and confequently at Reft. Moreover, if the Waters were moved by any Preffure, it would be towards the Shores, where the Paffage is more open than the fmall Fiffures of the Earth. And tho' there be great outlets at the bottom of the Sea, for the Water to flow through, yet fince it is falt, it cannot make fresh-water Fountains. I think the true Anfwer to this Argument is not far to fetch, if, we confider how Water is conveyed to Fountains, not by any Chanel or Pipe from the bottom of the Sea, or the Root of the Mountain (by which means it would still keep it's Saltnefs), but by a continual diftilling, gleeting, and ftraining of the watery Particles thro' the terreftrial Matter, till they find a Receptacle fit to collect and condenfe them into Drops, where being continually fucceeded by

others,

others, they have recourfe to fome Conveyance, and through it break forth at a Fountain. And we obferve this very thing in Mines dug to a vast Depth, how that Water on every Side is continually dropping, and collecting itself into small Guts, which they call Veins of Water; and if feveral fuch Guts or Runnels as thefe concur in one Receptacle, they form a Fountain, as they who make Drains, to bring Water into Wells, very well know. For in moft Draw-Wells the Water is collected from the dropping of the Earth, round about into the bottom of the Well; and they that make Aqueducts dig fmall Furrows in Gutters to collect the Waters, and then convey it in a large one to the intended Place. If it be objected, that many Fountains are obferved to fpring up among Rocks, where it is likely the watery Particles can scarce be admitted; I answer, That this confirms our Opinion; for thefe Rocks are not continued to the foot of the Mountain (upon which fuch Springs are found) but only cover the Surface to a fmall Depth, and the Earth is lighter and lefs rocky within, or at leaft fit to give Admiffion to the Water, which, when it comes to the Strata of the Stones, can penerate no farther, but is there impeded and collected into Drops, and breaks out into a Fountain among the Rocks, if it can find any Aperture. Moreover, the rocky Mountains in the Ifland of St Helena, and in most other Islands, are not within fo denfe and obdurate, as appears from the Cinders, Afhes, and fulphureous Earth; which fhews that thefe Mountains. fome time or other burnt or fmoaked. And to this we may add, that the Fountain is not always in the Place where the Water breaks out, which is conveyed very often from a higher Place, by a Chanel under Ground, and this caufes it to break forth with greater Violence, as is very often obferved.

We may be further convinced of the Truth of these Things, by confidering that Fire will tend downwards thro' a Continuation of Matter, tho' of it's own Nature, when it is free from Matter, it tends upwards, Thus if you put one End of a Bar of Iron into the Fire, it will penetrate thro' the whole, and heat the other End, tho' it be turned downwards. And this is fufficient to convince any one of the Invalidity of the first Argument.

TO the Second we answer, That the Reason why the Sea-Water doth not penetrate and fink into the Earth towards the Center, fo much as into the Mountains, is, becaufe the Earth there is denfer, and full of Metals, as we find by Experience; but where it is not fo obdurate, the Water glides in, and therefore if there are Receptacles under the bottom of the Sea, we do not deny but that there may be fome fresh and falt Water Lakes there. But becaufe there are few fuch Receptacles, and the Earth every where is denfe and metalline, under the bottom of the Sea, it cannot conftantly imbibe Water; but when it is faturated it receives no more, and then the overplus Water diftils towards the higher Places. And the Sea conftantly changing it's Altitude, and fluctuating backwards and forwards, may contribute much to elevate the Water; for where it is higher than ordinary, it must certainly prefs the Water into the Earth, and drive it to the Fountain-Heads. And fince the Surface of the Ocean in every Place is conftantly agitated, and made higher and lower, not only by Storms, but alfo by the Tides, therefore fuch a Preffure as this muft happen every Day. But I queftion whether this can do much.

TO the third Argument we fay, That this is owing to the Difpofition or Situation of the Strata of the Earth, or of the Earth itfelf, and that it is

the

the nature of all Fluids to gather to a Head, where there is a Flux. I think there is no need of faying any more to this.

BUT the fourth is not fo eafily anfwered, for we do not perceive Salt to be separated from SeaWater only by Percolation or Straining. Befide, there are two kinds of Salt in Water (which the Ariftotelians did not confider) the one of which is very well named, by Chymifts, fixed, and the other volatile. The fixed Salts may indeed, by continual straining, or boiling, or diftilling of the Sea-Water, be feparated from it; but the volatile Salt is fo full of Spirit, that it flies up with the Water, and cannot be feparated from it, neither by frequent Diftillations nor any other Art hitherto used. Therefore it is very difficult to fhew how this volatile Spirit of Salt is separated from the SeaWater, in it's Paffage from the Ocean to FountainHeads. The following Accounts will ferve our Turn. 1. Tho' we have not found out the Art of feparating the volatile Spirit of Salt from Sea-Water, yet we cannot deny but that it may be done, fince we fee it feparated by Nature, when it rains fresh Showers in the main Ocean, tho' they proceed from Vapours exhaled from the Sea. 2. The Particles of falt Water which pervade the Fiffures of the Earth, before they come to their Fountain, are mixed with other fresh Water, which proceeds from Rain and Vapours condensed there, whereby the fmall Degree of volatile Salt that remains in them is rendered infenfible. 3. It is not true that all Fountains are entirely deprived of Saltnefs, for there are fome falt Springs, as we faid before, about two Miles from Suez, and in feveral other Places not fo far from the Sea. Therefore to separate the volatile Salt from the Water, a long Tranfcolation, and a gentle Evaporation is required, and thus it is to be feparated by Art; and

thus

thus alfo is Rain-Water generated and made fresh; tho' fometimes faltish Showers are obferved to fall into the Sea.

THE Water of Springs therefore proceeds partly from the Sea, or fubterraneous Water, and partly from Rain and Dew that moiftens the Earth. But the Water of Rivers proceeds partly from Springs, and partly from Rain and Snow.

PROPOSITION VI.

Some Rivers in the middle of their Courfe, hide themfelves under Ground, and rise up in another Place, as if they were new Rivers.

THE moft famous are:

1. THE Niger, a River in Africa, which fome antient Cofmographers would have to proceed from the Nile, by a fubterraneous Chanel, because it overflows it's Banks at the fame Time of the Year, and after the fame manner that the Nile does and they could not fhew a better Caufe for it's Inundation. This River meeting with the Mountains of Nubia, hideth itself under them, and emerges again on the Weft Side of the Mountains (c).

2. THE Tigris in Mefopotamia, after it has paffed the Lake Arethusa, meets with Mount Taurus, and plunges itself into a Grotto, and flows out at the other Side of the Mountain; alfo after

(c) This River hides itself no where under Ground that we know of; tho' perhaps we are not certain whether it do or no, because no European has traced it to it's Fountain: Only the Zeebe, a large Branch of it, (which proceeds from the Lake Zaire, and was fome time fince

taken for the upper Part of the Nile) meeting with the Mountains of Nimeamay, is faid to divide itself into feveral fireams, and immerge under them, and to emerge again on the North fide of the Mountains. But I do not write this as a Certainty.

it