268 ANNUAL OF SCIENTIFIC DISCOVERY. 



take, in their general channels of circulation over the northern conti- 

 nents. The country between these two lines is the country which, in 

 the general system of atmospherical circulation, lies under the lee of 

 S. E. trade wind of Africa and America. And to see where this country 

 is, we have first to ascertain where those two points on the Equator 

 are between which the S. E. trade winds cross, after having traversed 

 the greatest extent of land surface in South America, and then from these 

 points to project lines in the direction which these winds are supposed 

 to take, after rising up in the equatorial calms. These two points will 

 be, one near the mouth of the Amazon, the other not far from the 

 Gallipagos Islands. The part of the Equator between them is the part 

 crossed by the S. E. trades, after having traversed the greatest ex- 

 tent of land, from whose surface the supplies of moisture are most 

 scanty. A line from the Gallipagos, through Florence, in Italy, and 

 another from the mouth of the Amazon, through Aleppo, in Holy Land, 

 would, after passing the Tropic of Cancer, mark upon the surface 

 of the earth the route of these winds. This is that " lee country" 

 which, if such be the system, of atmospherical circulation, ought to be 

 scantily supplied with rains. The hygrographic map of Europe, in 

 Johnston's Physical Atlas, places the region of least precipitation be- 

 tween these two lines. It would seem that nature, as if to reclaim 

 this "lee" land from the desert, had stationed by the wayside of 

 these winds a succession of inland seas to serve them as a line of relays, 

 for supplying with moisture this thirsty air. There is the Mediterra- 

 nean Sea, the Caspian Sea, and the Sea of Aral, all of which are situ- 

 ated exactly in this direction, as though these sheets of water were 

 designed, in the grand system of aqueous arrangements, to supply with 

 fresh vapor winds that had already left enough behind them to make 

 an Amazon and an Orinoco of. 



The Andes were once covered by the sea ; for their tops are now 

 crowned with the remains of marine animals. When they and their 

 continent were submerged admitting that Europe in general outline 

 was then as it now is it cannot be supposed, if the circulation of 

 vapor was then such as I suppose it now to be, that the climates of 

 that part of the old world which is under the lee of those mountains, 

 were then as scantily supplied with moisture as they now are. When 

 the sea covered South America, the winds had nearly all the waters 

 which now make the Amazon to bring away and to distribute among 

 the countries situated along the route ascribed to them. 



Is there any evidence that the basin which holds the Caspian Sea 

 has been more copiously watered than it is now 1 There is evidence 

 in favor of the probability that it has been, for portions of that sea 

 have retired and left salt-beds behind. If ever the Caspian Sea ex- 

 posed a larger surface for evaporation than it now does if the precipi- 

 tation in that valley ever exceeded the evaporation from it, as it does in 

 all valleys drained into the open sea then there must have been a 

 change of hygrometrical conditions there. And, admitting the vapor 

 springs for that valley to be situated in the direction supposed, the 

 rising up of a continent from the bottom of the sea, or the upheaval of 

 a range of mountains across their route in certain parts of America, 



