deposits, which are indirect proofs of a decrease of evapo- 

 rating surface. But there are in Asia, Africa, North and 

 South America, still existing hodies of salt water that hear 

 the most unmistakahle witness to a constant decrease of 

 precipitation in their gradually lowering levels. 



It is deemed unnecessary in this paper to refer especially 

 to these remarkable localities, as their peculiar character- 

 istics are too interesting not to he familiar to all physicists. 



The Dead Sea, the most remarkable of these grand 

 evaporation gauges, is about 1,300 feet below the level ot 

 the Mediterranean Sea. The whole Aralo-Caspian, and 

 lied Sea formations bear the most undoubted evidence of 

 u decrease of precipitation and constant lowering of water 

 level upon the continent of Asia. 



Lieut. Maury has demonstrated such to be the fact. 



Lake Tadjara, the great salt lake of Central Africa, is 

 500 feet below the ocean level, and is salting up. The 

 Bahr Assal, which once formed its continuation, has shrunk 

 to an elliptical basin, is half filled with water of the deepest 

 cerulean blue, and half with a glittering sheet of sand 

 white salt. Southern Africa is also said to have similar 

 formations. 



The lake of Utah is the basin which receives the drain- 

 age of this inland North American water shed. Its surface 

 is lowering, its waters salting up, and the channel which 

 once received the excess of drainage and returned it to the 

 ocean is distinctly traceable, as are channels from most of 

 the other salt lakes. 



Lake Titicaca is but slightly brackish, and is supposed 

 not to have been standing long enough to show any re- 

 markable decrease of level, existing as it does upon the 

 last emerged continent of South America. 



If Maury has proved that the water surfaces that supply 

 the precipitation of Western Asia have dimkiished in ex- 

 tent, these salt lakes and saline deposits upon every continent 

 and many islands, bear witness to the general truth that the , 

 evaporating surfaces have evergwliere deceased. 



s 



