S8 Qn the Hypotheses of Galvanism. [Feb. 



zelius, which was afterwards adopted and extended by Sir H. Davy. 

 It supposes that when electricity is transmitted through a fluid, the 

 fluid becomes affected in such a manner that the elements of which 

 it is composed are attracted to the different wires, and the fluid 

 itself decomposed; the hydrogen, and all inflammable substances, 

 passing to the negative j while oxygen and acids are attracted to the 

 positive wire.* 



I shall now attempt to explain the nature of the effect which 

 must be produced upon the water according to the first of these 

 hypotheses. The positive wire, A, and the negative wire, B, being 

 immersed in water, the electricity rushes from A to B to produce 

 an equilibrium between them, and this current of electricity is kept 

 up in consequence of the continued evolutioti from the body of the 

 pile. But electricity cannot be conveyed through water except in 

 combination with hydrogen : it therefore decomposes the particles 

 of water that are contiguous to the point of the wire, takes pos- 

 session of the hydrogen, and discharges the oxygen ; it then crosses 

 the fluid, and discharges the hydrogen at the negative wire. There 

 wnll be a continued current of hydrogen at all times passing through 

 the fluid ; but being in combination with electricity, it does not 

 display its usual affinities. This current of hydrogen must exist in 

 an equal degree in all parts of the water interposed between the 

 wires, and must continue as long as the pile continues to act. It is 

 obvious that there can be no current of oxygen through any part of 

 the water, except from the end of the positive wire to the surface j 

 nor can there be any accumulation of either this substance or 

 hydrogen, except perhaps at the immediate termination of the 

 wires. The discharge of the oxygen and hydrogen from the tvi'o 

 wires respectively is supposed to depend, not upon any direct action 

 which the wires exert on the w£\ter, but upon the electricity ab- 

 stracting a portion of hydrogen which it afterwards liberates. 

 iFig. 5.) 



The mark x is intended to express the union of hydrogen and electricity. 



According to the other hypothesis, the effect produced depends 

 upon the attraction which the two wires possess for the two consti- 

 tuents of the water, the positive wire for the oxygen, and the 

 negative wire for the hydrogen j so that as soon as A and B arc 



» Ann. de Cblm. li. 167. 



