TRADE-WINDS OF THE SOUTHERN HEMISPHERE. 361 



evaporation or diminislied bj temporary condensation. The prO' 

 pelling poiver of the winds in the southern hemisphere resides chiefly 

 in the latent heat of the vapor which they such up from the engirdling 

 sea on the polar side of Capricorn. 



The Storm and Kain Charts show that within the trade-wind 

 regions of both hemispheres the calm and rain curves are symmet- 

 rical ; that in the extra-tropical regions the symmetry is between 

 the calm and fog curves ; and also, especially in the southern 

 hemisphere, between the gale and rain curves. 



Lieutenant Yan Gogh, of the Dutch navy, in an interesting pa- 

 per on the connection between storms near the Cape of Good Hope 

 and the temperature of the sea,"^ presents a storm and rain chart 

 for that region. It is founded on 17,810 observations, made by 

 500 ships, upon wind and weather, between 14° and 32° E. and 

 33° and 37° S. 



By that chart the- gale and rain curves are so symmetrical that 

 the phenomena of rains and gales in the extra-tro|)ical seas pre- 

 sent themselves suggestively as cause and effect. The general 

 storm and rain charts of the Atlantic Ocean, i)repared at the Na- 

 tional Observatory, hold out the same idea. Let us examine, ex- 

 pand, and explain this fact. 



1012. We ascribe the trade-winds to the equatorial calm-belt. 

 But to what shall we ascribe the counter-trades, particularly of 

 the southern hemisphere, which blow with as much regularity to- 

 ward the pole as the northeast trades of the Atlantic do toward 

 the equator? Shall we say that those winds are drawn toward 

 the south pole by heat^ which causes them to expand and ascend 

 in the Antarctic regions ? It sounds somewhat paradoxical to say 

 that heat causes the winds to blow toward the poles as well as to- 

 ward the equator ; but, after a little explanation, and the passing 

 in review of a few facts and circumstances, perhaps the paradox 

 may disappear. 



It is held as an established fact by meteorologists that the aver- 

 age amount of precipitation is greater in the northern than in the 

 southern hemisphere ; but this, I imagine, applies rather to the 

 land than the sea. On the polar side of 40°, it is mostly water in 

 the southern, mostly land in the northern hemisphere. It is only 



* De Stormen nabij de Kaap cle Goede Hoop in verband beschouwd met de Tem- 

 peratuur der Zee. 



