THEORY OF GALVANISM. 
107 
a pair of balls diverge as well when negative as when positive, 
on which the then prevalent theory of y'Epinus introduced the 
most uncouth association of hypotheses. Volta put also a 
Stop to these fanciful theories, by proving, that it is not by re- 
pulsion, that the balls of the elecfroscojjes recede from each 
'other, either positively or negatively; but by each of them 
being carried towards the air on the outside of them, the elec- 
tric state of which differed more from their own than that of 
the air between them, as they both contributed to bring it to 
their electnic state. This solution, both simtrle and founded 
« * ‘ 
on direct experiments, has removed all the difficulties which 
the motions of the electroscopic balls bad prresented at first to 
electricians. 
It is from that theory which Sig. Volta had explained to me, 
’ with many other particulars in our conversation, that 1 soon 
I understood the plienomenoii of the electric column, which 
I made me add to its first appellation that of aerial electroscope. 
'The surrounding air acts constantly to lessen the difference 
1 which naturally exists between the electric states of the e\tie- 
imities of the column; taking some electric fluid from the 
I positive, and imparting some to the negative, but more or less 
• according to its own electric state, which, by its phenomena as 
• an aerial electroscope, is found to be variable ; and this circum- 
• stance would afford a new prtxif (if any were wanting) that 
thd difference which exists between the extremities of tire co- 
llumn, consists in the quantity of electiic fluid. 
Tliis preliminary statement was necessary to explain the 
t cause of the great increase of power in Mr. Singer s column, 
(produced by inclosing each lOOO pairs of plates in a glass tube ; 
.and, in this respect again, though having that previous know- 
I ledge, I should not have conceived how far this increase ex- 
tended, had not Mr. Singer been so good as to send me one 
(of these parts of 1000 pairs of his column, the power of which, 
(compared to the same number of my column, has astonished 
me; but I soon conceived the cause of that difference, which 
II now can explain. 
The air confined in these glass tubes, has very little commu- 
1 2 nication 
Excitement o ' 
ealvanic elec 
tricity, and 
phenomena of 
the electric 
column. 
