186 THE PHYSICAL GEOGRAPHY OF THE SEA. 



surface would grow less and less, until Nature should establish 

 the proper ratio between the ability of the air to take up and the 

 capacity of the clouds to let down. Thus we might have a sea 

 whose level would be much farther below the water-level of the 

 ocean than is the Dead Sea. 



380. There is still another process, besides the tw^o already al- 

 luded to, by which the drainage of these inland basins may, 

 through the agency of the winds, have been cut off from the great 

 salt seas, and that is by the elevation of continents from the bot- 

 tom of the sea in distant regions of the earth, and the substitution 

 caused thereby of dry land instead of water for the winds to blow 

 upon. 



381. Now suppose that a continent should rise up in that part 

 of the ocean, wherever it may be, that supplies the clouds with 

 the vapor that makes the rain for the hydrographic basin of the 

 great American lakes. What would be the result ? Why, surely, 

 fewer clouds and less rain, which would involve a change of cli- 

 mate in the lake country ; an increase of evaporation from it, be- 

 cause a decrease of precipitation upon it ; and, consequently, a 

 diminution of cloudy screens to protect the waters of the lakes 

 from being sucked up by the rays of the sun ; and consequently, 

 too, there w^ould follow a low stage for water-courses, and a low- 

 ering of the lake-level would ensue. 



So far, I have instanced these cases only hypothetically ; but, 

 both in regard to the hydrographical basins of the Mexican Gulf 

 and American lakes, I have confined myself strictly to analogies. 

 Mountain ranges have been upheaved across the course of the 

 winds, and continents have been raised from the bottom of the 

 sea ; and, no doubt, the influence of such upheavals has been felt 

 in remote regions by means of the winds, and the effects which a 

 greater or less amount of moisture brought by them would produce. 



382. In the case of the Salt Lake of Utah, we have an example 

 of drainage that has been cut off, and an illustration of the process 

 by which Nature equalizes the evaporation and precipitation. To 

 do this,' in this instance, she is salting up the basin w^hich received 

 the drainage of this inland w^ater-shed. Here we have the ap- 

 pearance, I am told, of an old channel by which the w^ater used 

 to flow from this basin to the sea. Supposing there was such a 

 time and such a water-course, the water returned through it to 



