ON THE GEOLOGICAL AGENCY OF THE WINDS. igi 
394. The range which Hes between the two lines that represent 
the course of the American winds with their vapors, and the two 
lines which represent the course of the African winds with their 
vapors, is the range which is under the lee of winds that have, for 
the most part, traversed water-surface, or the ocean, in their cir- 
cuit as southeast trade-winds. But a bare inspection of Plate VII. 
will show that the southeast trade-winds which cross the equator 
between longitude 15° and 50° west, and which are supposed to 
blow over into this hemisphere between these two ranges, have 
traversed land as well as water ; and the Trade-wind Chart* shows 
that it is precisely those winds which, in the summer and fall, are 
converted into southwest monsoons for supplying the whole extent 
of Guinea with rains to make rivers of. Those winds, therefore, 
it would seem, leave much of their moisture behind them, and pass 
along to their channels in the grand system of circulation, for the 
most part, as dry winds. Moreover, it is not to be supposed that 
the channels through which the winds blow that cross the equa- 
tor at the several places named, are as sharply defined in nature 
as the lines suggested, or as Plate VII. would represent them to be. 
395. The w^hole region of the extra-tropical Old World that is 
included within the ranges marked, is the region which has most 
land to windward of it in the southern hemisphere. Now it is a 
curious coincidence, at least, that all the great extra-tropical des- 
erts of the earth, with those regions in Europe and Asia which 
have the least amount of precipitation upon them, should lie within 
this range. That they are situated under the lee of the southern 
continents, and have but little rain, may be a coincidence, I ad- 
mit ; but that these deserts of the Old World are placed where 
they are is no coincidence — no accident : they are placed where 
they are, and as they are, by design ; and in being so placed, it was 
intended that they should subserve some grand purpose in the ter- 
restrial economy. Let us see, therefore, if we can discover any 
other marks of that design — any of the purposes to be subserved 
by such an arrangement — and trace any connection between that 
arrangement and the supposition which I maintain as to the place 
where the winds that blow over those regions derive their vapors. 
396. It will be remarked at once that all the inland seas of 
Asia, and all those of Europe except the semi-fresh-water gulfs of 
* Series of Maury's Wind and Current Charts. 
