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MB. T. HOPKINS ON THE INFLUENCE OP BtTN'HEATED LAND 



wind of the part is admitted to be the eastern trade wind, and 

 it is stated that there only " sometimes arises a west wind," 

 and it is characterised as " a remarkable phenomenon." It is 

 well known that winds blow to some extent, on all coasts, from 

 the sea to the land, because there are generally some elevations 

 on the land, not far from the sea, up which air ascends when 

 cloud is formed and rain falls. But such winds are more 

 feeble and less constant on this than on other coasts ; indeed, 

 they are so much exceptions to the general state of the part as 

 to be unnoticed by nearly all the writers that I have happened 

 to meet with. If, however, this immense desert acted on the 

 atmosphere in the way assumed, the west wind from the cool 

 sea would be nearly always blowing, and would be very strong 

 during the summer days. This coast is but little known, but 

 on some maps hills or mountains are marked, and there may 

 be such sufficiently high to produce occasional rains. This 

 is most likely the fact, as the mouths of a number of short 

 rivers are marked on the maps, such as the River Cyprian, in 

 latitude 22°, and the River Del Ouro, near the tropics. As, 

 however, Humboldt states that the cause of the west wind 

 is the same as that which produces land and sea breezes on 

 coasts, and as there are no accounts of daily sea breezes 

 along these coasts — though they are known to exist south- 

 ward at Sierra Leone, — even the statement of this eminent 

 philosopher proves little more than that, in the great extent 

 and variety of his inquiries, he has sometimes adopted the 

 general opinions which he found in books, without carefully 

 examining the evidence on which they rest. 



To enable us to reason upon the real causes that produce 

 ascending currents, let us suppose that a broad belt of the 

 present equatorial land was all low and flat like the Valley 

 of the Amazon, and that mountains similar to those existing 

 at present in America and Africa in certain parts about the 

 equator extended across the Atlantic Ocean, on the outside 



