QO CIRCULATION OF THE WINDS. 



and a half millions of people are said to have perished. " * 

 We merely cite these facts as an illustration of the 

 enormous importance which the natural sequence of 

 rain-bearing winds in some cases assumes. The trade 

 winds, as we have stated, on the high authority of 

 the late Lieut. Maury, are the principal evaporat- 

 ing and rain-bearing mediums. We wish we could 

 find space for a more complete survey of this, one of 

 the most wonderful of all natural phenomena, but 

 we must content ourselves with offering but a single 

 quotation from Lieut. Maury's works, in support of 

 what we have already stated upon this subject. 



"The S.E. trades enter the Northern hemisphere, and as 

 an upper current bear into it all their moisture." "All the 

 air which comes loaded with moisture from the other he- 

 misphere, travels in the upper regions of the atmosphere, 

 until it reaches the calms of Cancer: here it becomes the 

 surface wind that prevails from southward and westward; as 

 it goes north it grows cooler and condensation commences. 

 We may liken it to the wet sponge, and the decrease of 

 temperature to the hand that squeezes the sponge. Finally, 

 reaching the cold latitudes, all the moisture that a dew point 

 of zero, or even far below, can extract, is wrung from it," f 



and subsequently, we may add, this air returns 

 towards the southward as dry atmosphere, and re-enters 

 the trade wind regions to recommence its round of 

 duty. Such, in brief, is the general outline of the 

 atmospheric circulation of our world varied and modi- 

 fied, according to local causes, in a thousand ways, 

 we need hardly say which it would be quite out of 



* Haydn's Dictionary of Dates Article "Famines." 

 f The Physical Geography of the Sea, by Lieut. Maury, U.S.N., 

 1877, pp. 118 and 119. 



