THEORY OF GALVANISM. 
opposite electricities tend to an equilibrium. The third pair 
loses a share of its electricity, which is gained by the first } and 
the intermediate pair, being placed between opposite forces of 
perhaps equal amount, remains in equilibria . Hence, in every 
galvanic arrangement, there must be a pair of plates, at or near 
the centre in the natural state of electricity. A communica- A pilecom- 
tion between the two extremities of a pile would therefore re- 
1 3. ClLCitj 
duce it to a state of permanent inaction, if there did not still by its electro* 
exist some cause, capable of disturbing the equilibrium. On 
the hypothesis of Volta, this can be nothing else than the pro- 
perty of electro motion in the metallic plates, which has been 
described as the primary cause of all the phenomena. 
This theory, on first view, appears sufficiently to explain the j n this theory 
facts on electrical principles, without the interference of che- fi ui( ^dif- 
1 r ’ fer only by 
mical action. Consistently wdth the hypothesis, different fluids, their conduct’ 
when made parts of Voltaic arrangements, produce effects lr ’^ P owei '* 
more or less energetic, as they are more or less active in con- 
ducting electricity $ the only property, according to Volta, that 
can be considered as influencing their efficiency in the pile. 
There are several facts, however, which, if not absolutely irre- 
concilable with the hypothesis, are certainly not at all explained 
by it. Why, for instance, it may be asked, when pure water 
forms a part of the arrangement, is the action of the pile sus- 
pended by placing it in an exhausted receiver, or in any of those 
gases that are incapable of supporting oxidation? Why is its ^ ^ ^ ^ ^ 
efficiency increased by an atmosphere of oxigen gas, or by ad- n A a*ree with 
ding to the water in the cells several fluids in a proportion not t * ie ^ act!! * 
sufficient to change materially its conducting power ? Why 
is the nitric acid, though a worse conductor of electricity 
than the sulphuric, more active in promoting the energy 
of the apparatus ? Why is the power of these combina- 
tions proportional to the disposition of one of the metals 
composing them to be oxidized by the interposed fluid ? These T}, e fluids mpe- 
facts undoubtedly suggest that, in some way or other, the che- rate by elle * 
mical agency of the fluids employed is essential to the sustained 
activity of the pile. The principle has even been conceded by 
some 
