9S 
rriEORY OF GALVA!«ISM, 
Kxcitonicni oi succef sive pairsj of zinc and copper, or silver plates; these 
galvanic elec- . , . . . , 
iricitv, and P'*'*'® he mg separated oy some non-metallic conducting sub- | 
ule^el*ectric other operation, eniirdy distinct from the former, 
coluimi. although (.’’wing to it its origin, is to produce chemical effects; 
and this dej^f^nds on some liquid being interposed between the 
metals in eac b pair ; whence results a particular modification 
of the electric' fluid. 
Having discc'Vered, by the phenomena of the galvanic pil« 
itself, these two idistinct functions, I conceived that they might 
be separated in .tn apparatus which, retaining the faculty of 
' setting in motion tl'ie electric fluid, should not produce any 
chemical effect, since' nothing was required but to suppress the 
liquid. 1 made the trial, and this is the origin of the appara- 
tus, which 1 have nameii electric column, the effect of which 
is to set the electric flu.'d in motion, without any chemical 
effects, either in itself, or b>etween its extremities. These pre- 
liminaries are, 1 think, sufficient to introduce the subjects an- 
nounced in the title of this p.iper. 
I'hough the electric column, as a new electric apparatus, 
was, in my opinion, deserving the notice of experimental phi- 
losophers, I did not flatter myself to see it so much enlarged 
and improved as I have been first informed by your Journal of 
June last, in which I found Mr. George John Singer’s paper 
on his electric column, with an account of its astonishing phe- 
nomena. I could not, therefore, but be surprised to find, two 
months after, in your Journal for August, the paper of Dr. 
William Henry, treating of the theories of excitement of gal- 
vanic electricity, in which not only no mention is made of Mr. 
Singer’s electric column and its effects, but theories are suc- 
cessively offered, which oughno have been prevented by the 
description of the phenomena of the new apparatus. I must, 
therefore, suppose, that Mr. Henry, when he sent you his 
paper, had not any knowledge of those on the electric column 
preceding it, in your Journal ever since 1810 j and I know, 
from circumstances communicated to me by Mr. Singer him- 
.self, that when Mr. Henry wrote his paper, he could not know 
the existence of bis column. 1 herefore, after having detailed, 
iu 
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