290 SPECIAL RESULTS IN THE URANOLOGICAL 



of this great physicist had made it appear that all gases are 

 diamagnetic i. e. that they arrange themselves east and west 

 like bismuth and phosphorus (oxygen gas, however, the most 

 feebly so), his last train of researches, the commencement 

 of which goes back to 1847, shews that oxygen, unlike all 

 other gases in this respect, comports itself like iron in taking 

 a north and south axial direction ; and farther, that it loses 

 part of its paramagnetic force by rarefaction and increase 

 of temperature. As the diamagnetic quality of the other 

 constituents of the atmosphere nitrogen and carbonic acid 

 gas is not modified by expansion or by increase of tempera- 

 ture, we have only to consider the atmosphere of oxygen, 

 which surrounds the Earth like a dome of thin sheet iron 

 and receives magnetism from it. The half of the dome 

 which is turned towards the sun becomes less paramagnetic 

 than the opposite one, and, as by the Earth's rotation and 

 revolution roumd the Sun, the boundaries between these two 

 half domes are continually shifting their place, Faraday is 

 inclined to derive a part of the variations of magnetism on the 

 surface of our globe, from these thermic relations. The assi- 

 milation, by adequate experimental research, of one kind of 

 gas, oxygen, to iron, is an important discovery of the time in 

 which we live ( 489 ), and is of the higher importance, because 

 it is probable that oxygen constitutes almost the half of all the 

 ponderable matter belonging to the accessible portions of our 

 planet. Without the assumption of magnetic poles in the sun, 

 or of proper magnetic forces in the solar rays, the central 

 body of our system may excite magnetic activity on our 

 planet simply by its powerful agency as a source of heat. 

 The attempts which have been made to show, by meteo- 



