NATURAL HISTORY. 55 



and there arc some of the same sort both in Africa 

 and America. 



The most general and largest lakes, however, are 

 those which, having received another river, or many 

 small rivers, give rise to other great rivers. It is wor- 

 thy of remark, that all lakes from which rivers derive 

 their origin, all those which fall into the course of ri- 

 vers, and which carry their water to them, are not sa- 

 line. But almost all those, on the contrary, which 

 receive rivers, without other rivers issuing from them, 

 are saline, which seems to favour the opinion we have 

 laid down on the subject of the saltness of the sea, 

 for evaporation cannot carry off fixed salts, and con- 

 sequently those which rivers carry into the sea remain 

 in it; and although river water appears to taste sweet, 

 we know that it contains a small quantity of salt, and 

 in course of time the sea must have acquired a consi- 

 derable degree of saltness, which must still continue 

 to increase. Hence, in my opinion, the Black Sea, 

 the Caspian Sea, the lake Aral, the Dead Sea, &c. 

 are become salt. 



The lakes which are any ways remarkable are, the 

 Dead Sea, the waters of which contain much more 

 bitumen than salt ; this bitumen, which is called the 

 Bitumen of India, is no other than the Asphaltum, 

 which has induced some authors to denominate this 

 sea Lake Asphallum. The land which borders on 

 this lake contains a great quantity of bitumen, and 

 may have applied the fables to this lake, which the 

 poets feign of the lake Avernus, that no fish could 

 live in it, and that 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 in them without the least dan- 



