GALVANISM. 
as in the former experiments, the metal be- 
came revived. 
He next caused the galvanic current to 
pass through solutions of the muriates of 
lime and soda. In these experiments, he 
found the oxygen evolved from the wire of 
the zinc-end very deficient, and a smell of 
oxy-muriate produced. When gold wires 
were employed, tire gold was dissolved by 
the oxy-muriatic acid. Aqua ammonia 1 be- 
ing operated upon in a similar way, both 
the water and the alkali underwent decom- 
position, producing the gases of hydrogen, 
nitrogen, and oxygen. 
It is to the ingenious author of the above 
experiments, that we are indebted for the 
invention of the galvanic trough, a disco- 
very which very soon superseded the use of 
the pile, as being more manageable, and at- 
tended with less trouble to the operator. 
It consists of a wooden box, or trough, the 
depth and breadth of which corresponds 
with the size of the plates. It is of such a 
length, in general, as to contain fifty plates, 
allowing a space of about three-eighths of 
an inch, between each pair of plates. The 
spaces between the plates are formed by 
grooves, which are to receive the plates.The 
plates are first soldered together in pairs, 
one of copper or silver, and one of zinc. 
The trough being lined with a cement, 
formed of bees’-wax and resin, the plates, 
which are previously warmed, are pressed 
into the grooves, in such order, that the zinc- 
side of each compound-plate may face one 
way, and the copper or silver the other. 
It will be easily perceived, that there is 
the strictest analogy between the trough 
and the pile, in point of arrangement. See 
fig- 1 - 
The pair of plates of zinc and silver, 
which, in the pile, are simply laid upon 
each other, are, in the trough, soldered to- 
gether, and ^emented into the grooves; and 
the cavity or cells formed by the spaces be- 
tween each pair of plates, in the trough, be- 
ing filled with a solution of salt or other ap- 
propriate liquid, stands in the stead of the 
pieces of moistened cloth, between the 
plates of the pile. 
Several powerful troughs were soon after 
constructed, the effects of which were 
strikingly evinced in producing other phe- 
nomenon, not as yet observed. Very small 
wires and foils of metal being exposed in 
their circuit, were deflagrated with great 
brilliancy. 
A number of galvanic experiments were 
made by Dr. Henry, of Manchester, in 
which he succeeded in decomposing the sul- 
phuric and the nitric acids, and ammonia. 
Mr. Davy, professor of chemistry at the 
Royal Institution, made a number of expe- 
riments, the most particular of which were 
those, in which he ascertained, that the dis- 
similarity of metals was not absolutely es- 
sential to the galvanic process. He suc- 
ceeded first in exciting this energy by 
means of one metal, the two sides of which 
were separated from each other. An oxy- 
dating liquid, such as an acid, was placed 
on one side of the plate, and a liquid hav- 
ing a contrary effect on the other. He after- 
wards produced an effect though more faint- 
ly, by treating plates of charcoal in a similar 
way. Hence it would appear, from these 
results, that the dissimilarity of the metals 
was only necessary to the furnishing two 
surfaces of different degrees of oxydability. 
Hitherto it was not generally admitted, 
that the fluids of galvanism, and electricity, 
were identical. Dr. Wollaston made a 
number of experiments, which seem to have 
completely settled this point. He succeed- 
ed in decomposing water, by means of a 
current from the common electric machine. 
This effect, which had been performed with 
so much facility with the galvanic apparatus, 
was previously not known to be able to be 
produced by common electricity, and had 
hitherto appeared the most striking differ- 
ence between the two principles. 
This ingenious experimentalist, made a 
number of other experiments, tending to 
throw much light on the means of ex- 
citing and appreciating galvanic phenome- 
na. He immersed each extremity of a 
piece of zinc and silver in dilute muriatic 
or sulphuric acid. The zinc, as would be 
expected, immediately caused the disen- 
gagement of hydrogen gas, while no ap- 
pearance took place upon the silver. As 
soon, however, as the two metals were 
made to touch each other at the opposite 
extremities, bubbles of hydrogen were co- 
piously given out by the silver wire. Any 
other metal, capable of being acted upon 
by the acid, being substituted for the zinc, 
produced with the silver a similar effect. 
When gold was employed with silver, iron, 
or copper, in the dilute nitric acid, the same 
effect was produced ; the gold being the 
same with the silver in the first experi- 
ment. 
He made similar experiments, using me- 
tallic solutions instead of the dilute acid. 
Instead, however, of silver or gold giving 
out hydrogen gas, on the contact being 
