THERE are but fome few Rivers that pafs thro' fuch Lakes; the Nubia in Africa hath five, the Niger four, and the Rhone has the Lake of Geneva, &c.

mult

WE faid of thefe Lakes in the foregoing Chapter, that the River which runs in, be compared with that which runs out; and if this be larger than the other, there are certainly Springs in the Bottom which feed that Lake, and the River but if it be lefs, or of the fame bignefs, then is the Lake made and fed by the River which runs into it; and the Caufe of this Lake is the Breadth, Depreffion, and Concavity of the Chanel; and a Lake may be thus made in any River, as we faid before.

AND if the River which runs out, be in a direct Line with that which runs in, it is to be accounted the fame, or a Part of the fame River, tho' perhaps it may be greater or even lefs, yet I think it is not to be doubted but that it is still a Part of the fame.

YET the Rhone enters the Lake of Geneva, and flows thro' it, but doth not make or feed it; as appears from the different Colour of the Water of the Lake, and of the River, (and other things) neither doth the Rhone make any Lakes, but is wholly fed by Springs and Rivulets. Tho' I do not fay this is certainly true.

PROPOSITION XVII.

The further Rivers have run from their Fountains, the more they increase in Breadth; and are broadest at their Mouths.

THE Reason is; 1. Because that other Rivers mix with them, and continually increase them. 2. Because the Declivity of the Chanel is not fo

Y 3

great

great near the Mouth. 3. Because that Sea-Breezes frequently blow the Water up into the River near the Mouth, but do not affect it in Places near the Fountain. 4. The Sea-Water alfo enters the Mouth of the River when fuch Breezes blow, and makes it wider by it's violent Agitation,

THE fewer Mouths any River hath, the broader they are.

RIVERS remarkable for their broad Mouths are; the great River of the Amazons in South America, the River of St Laurence in Canada, the Zaire in Africa, and the Rio de la Plata in Brafil, This laft is faid by fome to be forty Leagues broad at the Mouth, tho' others fay but twenty; perhaps the former take in the other Mouths of this River, They that have been in Congo relate that the Mouth of the Zaire is twenty eight German Miles broad. Such Rivers as thefe pour fuch vaft quantities of Water into the Ocean, that they take away the Saltnefs of the Sea near the Shore, and disturb it's Motion, for twelve or fixteen German Miles round them.

PROPOSITION XVIII.

Rivers often carry along with them Particles of various Metals and Minerals; as alfo of Sand, and of fat and oily Bodies.

THE following Rivers are auriferous, that is, have Grains of Gold mixed with their Sands, viz. 1. Some in Japan. 2. Some in the adjacent Inlands to Japan. 3. A Brook called Arroë, which fprings from the Foot of the Mountains of the Moon in Monomotapa (where there are Gold Mines), and falls into the River Magnice, 4. Some in Guinea, where the Negroes gather the Grains, and feparate them from the Sand to exchange with the

Europeans,

Europeans, who fail thither for that Purpose. If the Particles are very small they call it Gold-Duft, which is the beft, and needs but little clear fing. 5. In all the Brooks about the City of Mexico, there are found Grains of Gold, efpecially after Showers of Rain; but there are feldom any found but in the rainy Seafons. 6. In Peru. 7. In Sumatra. 8. In Cuba. 9. In Hifpaniola, and other adjacent Inlands. 10. In Guiana, a Province of South America. 11. In the Rivulets of the Caribbees, there are found great Lumps of Gold after Showers of Rain. The Inhabitants caft Nets into the Rivers when thefe are out, and catch the Sand, from which they can easily separate the Gold. 12. There are feveral Rivers and Fountains in the Countries near the Alps in Germany, particularly in the County of Tyrol, from whofe Waters they extract Gold and Silver, tho' there be no Grains of either Metal to be perceived in the Water, they lies in fuch small Particles or Atoms. The Rhine also, and the Elbe has golden Clay in feveral Places. The Tagus, or Tago, a moft celebrated River in Spain was formerly famous for carrying Gold-Sands at the Bottom: but there are none now; nor do I hear of much Riches got that way out of any River in Europe, tho' fome boast of a fmall Rivulet in Heffe, which has Gold mixed with it's Sand; but I have not read it in any Author of Credit.

NO Rivers, which in like manner produce Silver, are taken Notice of by Authors; yet it is not to be doubted but there are as many if not more of this Sort alfo; only because Silver is not fo eafily difcerned from the Sand, and no great Profit is expected to requite the Pains of extracting it, no Body has thought it worth their while to take Notice of it. And for this Reafon there hath been no mention made of those Rivers that carry Grains of Iron, Copper, Tin, &c. except

SECT. IV. of fome few; tho' without doubt there are great Numbers of them in the World, at whofe furprizing effects Men are amazed; and fuperficial Philofophers have here recourfe to occult Qualities. If we obferve the River in High Germany which turns Iron into Copper (as is commonly thought), we admire that a Horfe-fhoe of Iron fhould, by hanging in it for fome Time, be turned into one of perfect Copper. But, in truth, the Iron is not changed into Copper (as is vulgarly fuppofed), but the Grains and Particles of Copper and Vitriol that are in this River, moving with the Water, corrode the Iron, whofe Particles being removed, thofe of Copper fucceed in their Places.

NEITHER is there much Notice taken of fuch Rivulets as are impregnated with various kinds of Earth, Salt, and other Foffils, but we fhall treat largely of mineral and metallic Springs, in the following Chapter.

FROM this Mixture of different Particles proceeds a strange Diverfity of Waters, in Rivers and Wells. Some Water if you boil Meat in it, makes it black, which is a Sign that it is impregnated with Iron; nor will Peafe boil foft fo foon in this, as in other Water that is fomething fat and oily. Neither can the fame Beer be made of different Waters. That Water which hath Particles of Iron in it we call hard Water; but if it be mixed with fat and oily Particles, we call it foft Water, The Elbe is a foft Water River, as we may call it, which (as Experience fhews) is owing to the clayey and fruitful Ground it washes. And every other variety of Water arifes from the different forts of Earth, thro' which the Spring or River is carried, whether it be clayey, rocky, or metallic, &c.

PRO.

PROPOSITION XIX.

The Waters of most Rivers differ in Colour, Gravity, and other Qualities.

FOR fome Waters are black and fome dusky, fome incline to a red Colour, and others to a white.

AND this difference is beft obferved when two Rivers meet, where we can difcern the Water of each diftinctly, after they have run fome Paces in the fame Chanel; alfo by this we may perceive their different Gravity, by Reafon that one tends more to the Bottom of the Chanel than the other.

THE Water of the River Ganges is accounted very light and wholefome, and the Emperor of Guzarat, or the Great Mogul, in whatever place he is, takes care that this Water be carried along with him in Bottles, of which he alone drinketh. Others will have the Nile to produce the foftest and most wholfome Water. Heavy Water is for the most Part impregnated with Iron or Mercury.

TO understand the Nature of great Rivers we must look into the Rivulets that compofe them (for the Rhine receives many mineral Rivers, and the Danube takes in fuch as carry Gold, Iron, Vitriol, &c.) from whence their different Qualities arife, tho' moft Fountains have fomething of these in them.

PROPOSITION XX.

Some Rivers, at a fet Time of the Year, rife beyond their Banks, and overflow the adjacent Countries.

THE first and most celebrated among these is the Nile, which fwells to fuch a degree that it covers

all