§ 534, 535. THE GEOLOGICAL AGENCY OF THE WINDS. 287 



534. In the basin of the Dead Sea, in the basin of the Caspian, 

 Precipitation and of the Sea of Aral, and in the other inland basins of 



evaporation in the . . • i t • 



Dead Sea vaUey. Asia, we are entitled to infer that the precipitation 

 and evaporation are at this time exactly equal. Were it not so, the 

 level of these seas would be rising or sinking. If the precipitation 

 were in excess, these seas would be gradually becoming fuller; 

 and if the evaporation were in excess, they would be gradually 

 drying up ; but observation does not show, nor history tell us, 

 that either is the case. As far as we know, the level of these seas 

 is as permanent as that of the ocean, and it is difficult to realize 

 the existence of subterranean channels between them and the great 

 ocean. Were there such a channel, the Dead Sea beinor the lower, 

 it would be the recipient of ocean waters ; and we can not conceive 

 how it should be such a recipient without ultimately rising to the 

 level of its feeder. 



535. It may be that the question suggested by my researches 

 mence come its ^^^ uo bearing upon the Dead Sea ; that local ele- 

 ^^^^''^ vations and subsidences alone were concerned in 

 placing the level of its waters where it is. But is it probable that, 

 throughout all the geological periods, during all the changes that 

 have taken place in the distribution of land and water surface 

 over the earth, the winds, which in the general channels of circu- 

 lation pass over the Dead Sea, have alone been unchanged? 

 Throughout all ages, periods, and formations, is it probable that 

 the winds have brought us just as much moisture to that sea as 

 they now bring, and have just taken up as much water from it as 

 they now carry off? Obviously and clearly not. The salt-beds, 

 the water-marks, the geological formations, and other facts traced 

 by Nature's own hand upon the tablets of the rock, all indicate 

 plainly enough that not only the Dead Sea, but the Caspian also, 

 had upon them, in former periods, more abundant rains than they 

 now have. Where did the vapor for those rains come from ? and 

 what has stopped the supply? Surely not the elevation or de- 

 pression of the Dead Sea basin. My researches with regard to the 

 ■y^nds have suggested the probability (§ 290) that the vapor which 

 is condensed into rains for the lake valley, and which the St. Law- 

 rence carries off to the Atlantic Ocean, is taken up by the south- 

 east trade-winds of the Pacific Ocean. Suppose this to be the 

 casCj and that the winds which bring this vapor arrive with it in 



