268 
THEORY OF GALVANISM. 
tion and annihilation of Galvanic energy are canied on in a 
circle, leaving unexplained that immense evolution of electricity, 
which is manifested by the most striking effects, both in 
occasioning the combustion of bodies, and in disuniting the most 
refractory compounds. 
Remarks. O n the whole, the electromotive power of the plates, and the 
The electro- v 1 
motion by the chemical agency of the interposed fluids, appear to be the only 
cliemlcTl^ ^ c * rci1mstances > that can be brought to explain the efficiency of 
agency of the the Galvanic pile. To decide which is to be considered as the 
operative.^ 01 * 1 cause ’ an ^ which as the effect, is a difficulty not peculiar to 
this case, but common to every other, where two events, that 
are invariably connected, are not distinguished by an appreci- 
able interval of time. The most defensible view of the 
subject, however, seems to me to be that which attributes the 
primary excitement of electricity to the chemical changes. But 
it may be questioned whether the whole of the effect arises 
from the oxidizement of the more oxidable metal ; and 
whether it is not essential to the activity of the pile that one at 
least of the elements of the interposed fluids should be incapa- 
ble of entering into union with the negative metal. For 
example, in a pile composed of zinc, copper, and solution of 
muriate of soda, the oxygen of the water and the muriatic acid, 
both of which are negative as to their electrical state, are 
attracted by the zinc, and have their electricities destroyed. 
But the hydrogen and alkali, having do affinity for copper, 
except what arises from a difference of electrical habitude, 
deposit upon that metal a part of their electricity. The 
electromotive power of these plates now becomes efficient, and 
determines the current to one end of the apparatus, in the 
manner already described in a former part of this essay. 
The decoin- Another series of Galvanic phenomena, the explanation of 
mterposed and which is attended with some difficulty, are the decompositions 
5ucto« C ° n " ^ 3t ta ^ G P^ ace * n ’ m P er ^ ect conductors, forming an interrupted 
circuit between the two extremities of the arrangement. When 
two wires, for example, which are inserted into the opposite 
ends of a tube containing distilled water, are connected with 
the extremities of the pile, the positive wire, if of an oxidable 
metal * 
