414 Dr. Faraday on the Diamagnetic conditions 



long, five inches wide, and five inches high. This was placed 

 on the ends of the great magnet, and the terminal pieces of 

 iron before described, placed in it. The box was covered 

 over loosely by plates of mica, and formed a long square 

 chamber in which were contained the magnetic poles and field. 

 All the former arrangements in respect of the magnetic field, 

 the delivery- tube, the catch-tubes, &c., were then made; and, 

 lastly, the box was filled with carbonic acid by a tube, which 

 entered it at one corner; and was, from time to time, supplied 

 with a fresh portion of gas, as the previous contents became 

 diluted with gases or air. Everything answered perfectly, 

 and the following results were easily obtained. 



Air passed axially, being less diamagnetic than carbonic 

 acid gas. 



Oxygen passed to the magnetic axis, as was to be expected. 



Nitrogen went equatorially, being therefore diamagnetic, 

 even in carbonic acid. 



Hydrogen, coal-gas, olefiant gas, muriatic acid and ammo?iia 

 passed equatorially in carbonic acid, and were fairly diamag- 

 netic in relation to it. 



Carbonic oxide was very fairly diamagnetic in carbonic acid 

 gas. Here the effect of oxygen seems to be very well illus- 

 trated. Equal volumes of carbonic oxide and carbonic acid 

 contain equal quantities of carbon ; but the former contains 

 only half as much oxygen as the latter. Yet it is more dia- 

 magnetic than the latter; so, that, though an additional volume 

 and quantity of oxygen, equal to that in the carbonic oxide, is 

 in the carbonic acid added and compresed into it, it does not 

 add to, but actually takes from, the diamagnetic force. 



Nitrous oxide appears to be slightly diamagnetic in relation 

 to carbonic acid ; but nitric oxide gas was in the contrary re- 

 lation and passed towards the axial line. 



Hence it seems that carbonic acid, though more diamag- 

 netic than air, is not far removed from it in that respect ; and 

 this position it probably holds because of the quantity of 

 oxygen in it. The apparent place of nitrous oxide close to it 

 appears, in a great measure, to depend on the same circum- 

 stance of oxygen entering largely into its composition. Still 

 it is manifest that the action is not directly as the oxygen, for 

 then common air would be more diamagnetic than either of 

 them. It seems rather that the forces are modified, as in the 

 case also of iron and oxygen, and that each compound body 

 has its peculiar but constant intensity of action. 



In order to make similar experiments in light gases, the 

 two terminal pieces of the magnet were raised, so that they 

 might be covered by a French glass shade, which, with its 



