§ 355. EASTING OF THE TRADE-WINDS, ETC. I59 



of Cancer, the prevailing winds on the surface are from this zone 

 toward the pole, and (Plate, § 215) that these winds return as A, 

 B, C through the upper regions from the pole ; that, arriving at 

 the calms of Cancer, this upper current, A, B, C, meets another 

 upper current, S, R, from the equator, where they neutralize each 

 other, produce a calm, descend, and come out as surface winds, 

 D, E, or the trade-winds ; and as T, U, or the counter-trades. 

 Now observations have shown that the winds represented by T, U 

 are rain winds ; those represented by D, E, dry winds ; and it is ev- 

 ident that A, B, C could not bring any vapors to these calms to 

 serve for T, U to make rains of; for the winds represented by 



A, B, C have already performed the circuit of surface winds as 

 far as the pole, during which journey they parted with all their 

 moisture, and, returning through the upper regions of the air to the 

 calm belt of Cancer, they arrived there as dry winds. The winds 

 represented by D, E are dry winds; therefore it was supposed 

 that these are, for the most part, but a continuation of the winds A, 



B, C. On the other hand, if the winds A, B, C, after descending, 

 do turn about and become the surface winds T, U, they would first 

 have to remain a long time in contact with the sea, in order to be 

 supplied with vapor enough to feed the great rivers, and supply 

 the rains for the whole earth between us and the north pole. In 

 this case, we should have an evaporating region at sea and a 

 rainless region ashore on the north as well as on the south side 

 of this zone of Cancer; but investigation shows no such region. 

 Hence it was inferred that B, C and R, S do come out on the 

 surface as represented by Plate I. But what is the agent that 

 should lead them out by such opposite paths ? According to this 

 mode of reasoning, the vapors which supply the rains for T, U 

 would be taken up in the southeast trade-wind region by 0, Q, 

 and conveyed thence along the route Q, R, S to T. And if this 

 mode of reasoning be admitted as plausible — if it be true that R, 

 S carry the vapor which, by condensation, is to water with show- 

 ers the extra-tropical regions of the northern hemisphere, Kature, 

 we may be sure, has provided a guide for conducting S, T across 

 this belt of calms, and for sending it on in the right way. Here 

 it was, then, at this crossing of the winds, that I thought I first 

 saw the footprints of an agent whose character I could not com- 

 prehend. Can it be the magnetism that resides in the oxygen of 



