In South America there is a small lake, the source of the Maragnon, and another larger which is the source of the river Paraguay; also the lake Titicares, which falls into the river Plata; two smaller lakes which flow into the same river; and some others, not very considerable, in the inland part of Chili. All lakes from which rivers derive their origin, those which fall into the course of rivers, and which carry their water thereto, are not salt. Almost all those, on the contrary, which receive rivers without others issuing thereout, are salt; this seems to favour the opinion that the saltness of the sea arises from the salts which rivers wash from the earth, and continually convey into it; for evaporation cannot carry off fixed salts, and consequently those which rivers carry into the sea remain therein. Although river water appears to taste fresh, we well know that it contains a small quantity of salt, and in course of time might have acquired such a considerable degree, as to occasion the present saltness of the sea, and which must still continue increasing. It is thus, therefore, as I imagine, that the Black Sea, the Caspian, lake Aral, &c. have become salt. With respect to lakes, which do not receive any river, nor from which does any issue, are either fresh or salt, according to their different origins; those near the sea are generally salt, and those remote from it are fresh, because the one has been formed by the inundations of the sea, and the others proceed from springs of fresh water. The lakes any ways remarkable are the Dead Sea, the waters of which contain much more bitumen than salt: it is called the Bitumen of Judea, but is no other than the Asphaltes, which has caused some authors to call it the Asphaltic Lake. The lands which border this lake contain a great quantity of this bitumen; and many have supposed, as the poets feign of lake Avernus, that no fish could live therein, and birds which attempted to fly over it were suffocated; but neither of these lakes produce such mortal events; fish live in both, birds pass over them, and men bathe therein without the least danger. At Boleslaw, in Bohemia, there is said to be a lake, wherein are holes, whose depth is unfathomable, from which impetuous winds issue, which are carried over all Bohemia, and in winter raise pieces of ice of an 100 weight in the air. A petrified lake in Iceland is also mentioned; and lake Neagh, in Ireland, has also the same property; but these petrifactions are no other than incrustations, like those made by the water of Arcueil. ARTICLE XII, OF THE FLUX AND REFLUX.