§825,-826. TEIE WINDS OF THE SOUTHERN HEMISPHERE. 441 



Ocean, prepared at the National Observatory, bold out the same 

 idea. Let us examine, expand, and explain this fact. 



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

 The "brave west ^^^^ ^o what shall wc ascribc the counter-trades, par- 

 raref2^tion''Tif the ticularlj of thc southcm hemisphere, which blow 

 antarctic regions. ^'j.]^ ^g much regularity toward the pole as thc 



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 toward 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 average amount of 

 precipitation is greater in the northern than in the southern hemi- 

 sphere ; 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 now and 

 then, and on rare occasions, that ships carry rain-gauges to sea. 

 We can determine by quantitive measurements the difference in 

 amount of precipitation on the land of the two hemispheres, and 

 it is the result of this determination, I imagine, that has given 

 rise to the general remark that the rain-fall is greater for the 

 northern than it is for the southern hemisphere. But we have 

 few hyetographic measurements for quantity at sea; there the 

 determinations are mostly numerical. Our observers report the 

 ''times" of precipitation, which, whether it be in the form" of rain, 

 hail, or snow, is called by the charts, and in this discussion, rain. 

 Among such a large corps of observers, rain is sometimes, no 

 doubt, omitted in the log ; so that, in all probability, the charts do 

 not show as many "times" with Tain as there are "times" actually 

 with rain at sea. This omission, however, is as likely to occur iu 

 one hemisphere as in the other. Still, we may safely assume that 

 it rains oftener in all parts of the sea than our observations, or the 

 rain charts that are founded on them, indicate. 



826. With the view of comparing the rains at sea between the 

 Relative frequency of parallcls of 55° aud 60°, both lu thc North and 

 rains and gales at sea. g^^^^^ Atkutic, wc havc taken from the charts the 



following figures : 



