222 THE PHYSICAL GEOGRAPHY OF THE SEA. 



that supply? The mere elevation of the rim and depression of 

 the lake basin (§ 614) would not cut it off. 



616. If we establish the fact that the Dead Sea at a former pe- 

 riod did send a river to the ocean, we carry along with this fact the 

 admission that when that sea overflowed into that river, then the 

 water that fell from the clouds over the Dead Sea basin was more 

 than the winds could convert into vapor and carry away again ; 

 the river carried off the excess to the ocean whence it came (§ 165). 



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

 of the Sea of Aral, and in the other inland basins of Asia, w^e 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 observa- 

 tion 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 subterrane- 

 an channels between them and the great ocean. Were there such 

 a channel, the Dead Sea being the lower, it would be the recipi- 

 ent of ocean waters ; and we can not conceive how it should be 

 such a recipient without ultimately rising to the level of its feeder. 



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

 has no bearing upon the Dead Sea ; that local elevations and sub- 

 sidences 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 dis- 

 tribution of land and water surface over the earth, the winds, 

 which in the general channels of circulation 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? Obvi- 

 ously and clearly not. The salt-beds, the water-marks, the geo- 

 logical 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 for- 



