In Sulphureous and Mineral Waters, the Sulphureous and Mineral Corporeal Motions, are Exterior, and not Interior, like Salt waters: but, there are several sorts of such waters; also, some are occasionally, others naturally so affected: for, some waters running through Sulphureous, or Mineral Mines, gather, like a rowling Stone, some of the loose Parts of Gravel, or Sand; which, as they stick or cleave to the rowling Stone; so they do to the running Waters; as we may perceive by those waters that spring out of Chalk, Clay, or Lime Grounds, which will
have some Tinctures of the Lime, Chalk, or Clay; and the same happens to Minerals. But, some are naturally Sulphureous; as for example, Some sorts of hot Baths are as naturally Sulphureous, as the Sea-water is Salt: but, all those Effects of Minerals, Sulphurs, and the like, are dividable from, and also may be joyn'd to, the Body of water, without any disturbance to the nature of water; as may be proved by Salt-water, which will cause fresh Meat to be salt; and salt Meat will cause Fresh-water to be salt. As for hot Baths, those have hot figurative Motions, but not burning: and the moist, liquid, and wet Nature of water, makes it apt to joyn, and divide, to, and from other sorts of Motions; as also, to and from its own sort.
[CHAP. XVIII. The Cause of the Ebbing and Flowing of the Sea.]
The Nature of water is to flow; so that all sorts of waters will flow, if they be not obstructed: but it is not the Nature of Water, to ebb. Neither can water flow beyond the Power of its Quantity: for, a little water will not flow so far as a great one. But, I do not mean by flowing, the falling of water from some Descent; but, to flow upon a Level: for, as I have said, all waters do naturally flow, if they be not obstructed; but, few sorts of water, besides Sea-water, ebbs. As for the Exterior Figurative Motions of water, in the action of flowing, they are an Oval, or a half Circle, or a half Moon; where the middle parts of the half Moon, or Circle, are fuller than the two Ends. Also, the figure of a half Moon, or half Circle, is concave on the inside, and convex on the outside of the Circle: but, these Figurative Motions, in a great quantity of water, are bigg and full, which we name Waves of Water; which waves flowing fast upon each other, presses each other forward, until such time as the half Circle divides: for, when the Bow of the half Circle is over-bent, or stretched, it divides into the middle, which is most extended: and when a half Circle (which is a whole wave of water) is divided, the divided Parts fall equally back on each side of the flowing waves: so, every wave dividing, after that manner, in the full extension, it causes the motion of ebbing, that is, to flow back, as it flow'd forward: for, the divided Parts falling back, and joining as they meet, makes the head of the half Circle, where the Ends of the half Circle were; and the Convex, where the Concave was; by which action, the ebbing Parts are become the flowing Parts. And the reason that it ebbs and flows by degrees, is, That the flowing half Circles require so much time to be at the utmost extension. Also, every wave, or half Circle, divides not all at one time, but one after another: for, two Bodies cannot be in one place at one point of time; and until the second, third, and so the rest, flow as far as the first, they are not at their full extension. And thus the Sea, or such a great Body of Water, must flow, and ebb, as being its nature to flow; and the flowing Figure, being over-extended, by endeavouring to flow beyond its power, causes a dividing of the Extended Parts, which is the Cause of the Ebbing.
But, whether this Opinion of mine, be as probable as any of the former Opinions concerning the Ebbing and Flowing of the Sea, I cannot judg: but I would not be mistaken; for the flowing of the water, is according to its Quantity; for, the further it flows, the fainter, or weaker it is.
[CHAP. XIX. Of OVERFLOWS.]
As for Overflows, there be many; and many more would be, if the waters were not hindred and obstructed by Man's Inventions. But, some Overflows are very Uncertain and Irregular; others, Certain and Regular, as, the flowing of Nilus in Egypt: but as for the distance of time of its flowing, it may proceed from the far Journey of those flowing-waters: and, the time of its ebbing, may be attributed to the great Quantity of Water; so that the great quantity of water, will cause a longer or a shorter time in the flowing or ebbing; and certainly the waters are as long a flowing back, as flowing forward.
As for Spring Tides, they are only in such a time when there is a Naturall Issue of a greater quantity of water: so that Spring-Tides are but once a Month, and Single-Tides in so many hours: but, many several occasions, may make the Tides to be more or less full.