82 ACTION OF MAGNETISM PART i. 



that magnetic light emanates from the negative or 

 warmth pole, and electric light from the positive or light 

 pole. These magnetic curves of light are precisely 

 similar to those assumed by iron filings from magnetic 

 action. 



The most remarkable of these experiments is the 

 absolute extinction of a powerful electric discharge by 

 magnetic action. Mr. G-assiot sent a discharge from a 

 voltaic water battery, containing 3,520 insulated cells, 

 into a tube filled with attenuated carbonic acid gas. 

 The discharge was so strong that it was capable of 

 passing through more than six inches of the gas, yet, 

 on the approach of a very powerful electro-magnet, the 

 stratifications were arrested as soon as they appeared, 

 as if blown out, and finally extinguished. A stratified 

 discharge, in vacuo, from 400 insulated cells of a nitric 

 acid battery, was extinguished by the large electro- 

 magnet of the Royal Institution ; the luminous strata 

 rushed from the positive pole of the battery, but under 

 the magnetic force they retreated ; cloud followed after 

 cloud with deliberate motion, appearing as if swallowed 

 up by the positive terminal. The amount of electricity 

 that passed through the tube appeared to be materially 

 increased by exciting the electro-magnet ; the discharge 

 was so intense on one occasion as to fuse half an inch 

 of the positive terminal. A very powerful magnet is 

 also capable of extinguishing a stratified discharge. In 

 fact, according to the law of the reciprocal action of 

 magnetism, the forces are equal in intensity and oppo- 

 site in direction. 



The electric discharge from an induction coil is dis- 

 continuous, or eruptive sparks of high tension are given 

 out producing stratified discharges. 



The discharge of the voltaic battery had hitherto been 

 considered absolutely continuous ; and so it is for 

 chemical action, whether of analysis or combination ; 



