MAGNETISM AND CIRCULATION OF THE ATMOSPHERE. I45 



have a consistency sufficient, with the lights of reason, to guide 

 us as we seek to trace the wind in his circuits? The winds ap- 

 proach these polar calms (§ 155) by a circular or spiral motion, 

 traveling in the northern hemisphere against^ and in the southern 

 vnth the hands of a watch. The circular gales of the northern 

 hemisphere are said also to revolve in like manner against the 

 hands of a watch, while those in the southern hemisphere tj-avel 

 the other way. Kow, should not this discovery of these three 

 poles, this coincidence of revolving winds, with the other circum- 

 stances that have been brought to light, encourage us to look to 

 the magnetism of the air for the key to these mysterious but 

 striking coincidences ? 



385. Indeed, so wide is the field for speculation presented by 

 these discoveries, that we may in some respects regard this gTcat 

 globe itself, with its " cups" and spiral wires of air, earth, and 

 water, as an immense " pile" and helix, which, being excited by 

 the natural batteries in the sea and atmosphere of the tropics, ex- 

 cites in turn its oxygen, and imparts to atmospherical matter the 

 properties of magnetism. 



386. With the lights which these discoveries cast, we see (Plate 

 I.) why air, which has completed its circuit to the whirl* about the 

 Antarctic regions, should then, according to the laws of magnet- 

 ism, be repelled from the south, and attracted by the opposite pole 

 toward the north. 



387. And when the southeast and the northeast trade-winds 

 meet in the equatorial calms of the Pacific, would not these mag- 

 netic forces be sufficient to determine the course of each current, 

 bringing the former, with its vapors of the southern hemisphere, 

 over into this, by the courses already suggested ? 



388. This force and the heat of the sun would propel it to the 

 north. The diurnal rotation of the earth propels it to the east ; 

 consequently, its course, first through the upper regions of the 

 atmosphere, and then on the .su.rface of the earth, after being 

 conducted by this newly-discovered agent across the calms of 

 Cancer, would be from the southward and westward to the north- 

 ward and eastward. 



* " It whirleth about coHtinually." — BihU. 



