30G 
THEOKY or GALVANISM. 
Kvcitfmont of in particular, is due the consolidation of Dr, Franklin’s theory 
plvanic dec- q|- positive and negative electrioities, in a manner which is 
fneitv, and ^ t> 
plienonieiia of first to be explained. 
the dearie Xhat theory, though true in itself, encountered at first strong 
column. 
oppositions, because it was not well determined. Positive apd ' 
negative states of every kind suppose an intermediate or neutrai 
point. Dr. Franklin, therefore, fixed one ; considering the ' 
neutral point between positive and negative electricities, as 
being thp electric state of the ground, which state he supposed a 
to be both natural and invariable ; and as this position w'ss a 
supposed also necessary to the theory of plus and minus, it 
was attacked under different forms; but especially Dr. Peart, !j 
consideiiiig that th«ory as applied to the motions of electro- H 
scopes in various cases, compared to a supposed invariable if 
electric state of the ground, made against it such objections as h 
I t'l 
Y ere never satisfactorily answered. [i 
If 
But Volta struck at the root of this dispute, by fixing the it 
true neutral point with" respect to the motions of the balls in [i 
the electroscopes, which discovery spread a great light on the l{, 
atmospheric phenomena. He placed that neutral point in the |{ 
actual electric state of the air in which the balls stood, a state 
Y'hich was variable, so that a pair of balls remaining them- 
selves in the same electric state, diverge differently when trans- | 
ported into a place, the air of which is in a different electric |{ 
state than the former 
This being a fact which I have ascer- 
tained by various experiments, could not but point out the in- 
fluence of the actual electric state of the air on those motions, 
which was to be explained. 
Volta derived that explanation from a true knowledge of the 
influence of the surrounding air on those motions; he proved 
that air itself possesses the electric fluid as well as the bodies 
which it surrounds ; that it tends to share it equally with them, 
imparting some to those which have proportionally less, and 
taking some from those which have proportionally more than 
itself. 
That discovery ako put an end to all the complicated theories 
by which it had been attempted to explain the phenomenon, that 
a pair 
I 
I 
it 
It 
