306 On the Theories of the 
standing this concession, he’ is disposed te 
consider the movement of electricity which - 
takes place on the contact of two metals, as 
the cause originally disturbing the equilibrium ; 
andthe chemical changes as secondary, and 
chiefly as efficient in restoring the balance. 
For example, in a pile of copper, zinc and 
solution of muriate of soda, in its condition of 
electrical activity, the communicating plates 
of copper and zine are in opposite electrical 
states. And solution of muriate of soda being 
composed of two series of elements, possessing 
contrary electrical energies, the negative 
oxygen and acid are attracted by the zinc; 
and the positive hydrogen and alkali by the 
copper. An equilibrium is thus produced, | 
but only for an instant ; for muriate of zinc is 
formed and hydrogen is disengaged. The 
positive energy of the zinc plates, and the 
negative energy of the copper ones, are con- 
sequently again exerted; and thus the precess 
of electromotion continues, as long as the 
‘chemical changes are capable of being car- 
ried on. . ee 
The most obvious objection, which presents 
itself against the theory of Mr. Davy, is, that 
‘if the chemical agents, forming part of # 
Galvanic arrangement, be merely effectual in 
restoring the electric equilibrium, no adequate 
