194 
THE PHYSICAL GEOGRAPHY OF THE SEA. 
design, the beautiful and exquisite adjustments that we see here 
provided, to insure the perfect workings of the great aqueous and 
atmospherical machine. This coincidence — may I not call it 
cause and effect ? — is between the hygrometrical conditions of all 
the countries within, and the hygrometrical conditions of all the 
countries without, the range included within the lines which I have 
drawn (Plate VII.) to represent the route in the northern hemi- 
sphere of the southeast trade-winds after they have blown their 
course over the land in South Africa and America. Both to the 
right and left of this range are countries included between the same 
parallels in which it is, yet these countries all receive more water 
from the atmosphere than they give back to it again ; they all have 
rivers running into the sea. On the one hand, there is in Europe 
the Rhine, the Elbe, and all the great rivers that empty into the 
Atlantic ; on the other hand, there are in Asia the Ganges, and all 
the great rivers of China ; and in North America, in the latitude 
of the Caspian Sea, is our great system of fresh-water lakes ; all 
of these receive from the atmosphere immense volumes of water, 
and pour it back into the sea in streams the most magnificent. 
403. It is remarkable that none of these copiously-supplied wa- 
ter-sheds have, to the southwest of them in the trade-wind regions 
of the southern hemisphere, any considerable body of land ; they 
are, all of them, under the lee of evaporating surfaces, of ocean 
waters in the trade-wind regions of the south. Only those coun- 
tries in the extra-tropical north which I have described as lying 
under the lee of trade-wind South America and Africa are scanti- 
ly supplied with rains. Pray examine Plate VII. in this connec- 
tion. It tends to confirm the views taken in Chapter V., p. 115. 
404. The surface of the Caspian Sea is about equal to that of 
our lakes ; in it, evaporation is just equal to the- precipitation. 
Our lakes are between the same parallels, and about the same 
distance from the western coast of America that the Caspian Sea 
is from the western coast of Europe ; and yet the waters dis- 
charged by the St. Lawrence give us an idea of how greatly the 
precipitation upon it is in excess of the evaporation. To wind- 
ward of the lakes, and in the trade-wind regions of the southern 
hemisphere, is no land ; but to windward of the Caspian Sea, 
and in the trade-wind region of the southern hemisphere, there 
is land. Therefore, supposing the course of the vapor-distributing 
