GALVANISM. 
5, 1798, at the age, of sixty, amid the tears 
of his friends and the public regret. 
GALVANISM, tiiis surprizing branch of 
philosophy has been denominated galva- 
nism, from Galvani, an Italian professor, 
whose experiments led to its discovery. 
In 1789, some time before he made the 
most important discovery, he was by ac- 
cident led to the fact, of electricity having 
the property of exciting contractions in the 
muscles of animals. Stimulated by the then 
prevailing idea of electricity being a prin- 
ciple inherent in animals, which acting upon 
the muscular susceptibility, was the imme- 
diate cause of muscular motion, he was in- 
duced to persevere in the inquiry, during 
the prosecution of which, he brought to light 
other facts, which laid the foundation of 
this valuable scientific acquisition. 
After having observed that common elec- 
tricity, even that of lightening, produced 
vivid convulsions in the limbs of recently 
killed animals, he ascertained that metallic 
substances, by mere contact, under particular 
circumstances, excited similar commotions. 
He found, that it was essential, that the 
forces of metals employed should be of 
different kinds. He applied one piece of 
metal to the nerve of the part, and the other 
to the muscle, and afterwards connected 
the metals, either by bringing them toge- 
ther, or by connecting them by an arch of 
a metallic substance ; every time this con- 
nection was formed the convulsions took 
place. The diversity in the metals employ- 
ed in these experiments appeared, in the very 
early stages of this enquiry, to be connected 
with their respective degrees of oxydability, 
the one being possessed of that property 
in a great degree, and the other little liable 
to the change. Hence zinc, and silver, or 
gold, was found to produce the greatest 
muscular contractions. 
The experiments of Galvani were con- 
firmed by many able philosophers, by whom 
they were repeated. Those who particu- 
larly distinguished themselves by their la- 
bours on the subject were Valli, Volta, Drs. 
Monro and Fowler. 
Galvani had theorised upon the phenome- 
na which he had observed to a considerable 
extent. He conceived, that the convulsions 
were produced by a disturbance of the elec- 
tricity inherent in animals, which was iden- 
tical with the nervous fluid, and that the 
metallic substances employed had not any 
other effect, than that of transmitting the 
electricity from the nerve to the muscles 
producing the contractions in question. 
Simon Volta, with much labour and in- 
genuity successfully opposed tire hypothesis 
of Galvani. He had recourse to those valu- 
able experiments made by Bennet, by 
which to explain the phenomena observed 
by Galvani. Bennet had some time be- 
fore observed, when plates of different 
metals were brought in contact, that one 
of the metals transmitted a portion of its 
electricity to the other, each of which, 
when separated, being at the same time 
insulated, evinced signs of contrary states 
of electricity. When the plates, for in- 
stance, were one of copper and the other 
zinc ; the former, while the two were in 
contact, gave a portion of its electricity to 
the latter. Hence, when they were sepa- 
rated, and thus presented to the electrome- 
ter, the copper exhibited signs of negative 
electricity, and the zinc that of positive. 
On this ground it was that Volta objected 
to the hypothesis of Galvani, and establish- 
ed the more plausible idea, that the elec- 
tricity was furnished by the disturbance 
of that fluid, arising from the contact of the 
different metals, and that the convulsions 
were excited by the stimulating effect of 
that active agent. It was in the investiga- 
tion of this experiment, that this truly in- 
genious philosopher was led to the discovery 
of the pile, which from its inventor has been 
called the Voltaic pile. This apparatus 
consisted, in combining the effects of a num- 
ber of pairs of the different metals, and by 
that means constituting a battery in gal- 
vanism, similar in effect to the Leyden 
vial in common electricity. 
As silver and zinc had been found in the 
minor experiments to produce the greatest 
effect, these metals were employed by Volta 
in the construction of his battery. The 
silver plates generally consisted of coins ; 
and the zinc plates were of the same size, 
being frequently-. cast in moulds made with 
the silver. The same number of pieces of 
cloth, pasteboard, or leather, of the same 
size, and steeped in solution of common salt, 
were also provided. The above substances 
were formed into a pile, in the following 
order : zinc, silver, wet cloth ; zinc, silver, 
wet cloth ; and so on, in the same order, till 
the pile beeame sufficiently high; If it 
were to be elevated to any considerable 
height, it was usual to support it on the 
sides w ith three pillars of glass, or varnished 
wood. 
The pile, thus formed, was found to 
unite the effects of as many pairs of plates 
as might be employed. Previously to 
