288 Lieut. Maury on the Probable Relation between 



With the lights which these discoveries cast, we see why 

 that air which has completed its circuit to the whirl* about 

 the Antarctic regions should then, according to the laws of 

 magnetism, be repelled from the south, and attracted by the 

 opposite pole towards the north. 



And when the SE. and the NE. trade winds meet in the 

 equatorial calms of the Pacific, would not these magnetic 

 forces be sufficient to determine the course of each current, 

 bringing the former with its vapours of the southern hemi- 

 sphere over into this by the courses already suggested \ 



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 it course first through the upper regions 

 of the atmosphere, and then on the surface 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 northward and eastward. 



These are the winds which, on their way to the north, 

 from the South Pacific, would pass over the Mississippi 

 valley, and they appear to be the rain winds there. Whence 

 then, if not from the trade-wind regions of the South Pacific, 

 can the vapours for those rains come % 



According to this conjecture, and not taking into account 

 any exceptions produced by the land and other circumstances 

 upon the general circulation of the atmosphere over the 

 ocean, the SE. trade winds which reach the shores of Brazil 

 near the parallel of Rio, and which blow thence for the most 

 part over the land, should be the winds which, in the general 

 course of circulation, would be carried towards northern 

 Africa, Spain, and the South of Europe. 



They might carry with them the infusoria of Ehrenberg, 

 but, according to this theory, they would be wanting in 

 moisture. Now, these portions of the old world are for the 

 most part dry countries, receiving but a small amount of pre- 

 cipitation. 



Hence the general rule : those countries to the north of 

 the calms of Cancer which have large bodies of land situated 



* " It whirleth about continually.*' — Bible. 



