GALVANISM. 
this no other effect had been produced 
than what resulted from the energy of a 
single pair of plates. A pile of 50 pairs of 
plates, with as many corresponding pieces 
of wet cloth, was found to give a pretty 
smart shock, similar to an electric shock, 
every time that a communication was made 
between the top and bottom of the pile. 
It was found, however, that little or no 
shock was perceived, when the hands, or 
other parts applied, were not previously 
moistened. It was also observed, that the 
effect was increased when a larger surface 
was exposed to the action of the pile. If 
the communication were made by touching 
the pile with the tip of each finger merely, 
the effect was not perceived beyond the 
joint of the knuckle ; but if a spoon, or other 
metallic substance, were grasped in mois- 
tened hands, the effect was felt up to the 
shoulder. If the communication be formed 
between any part of the face, particularly 
near the eyes, and another part of the body, 
a vivid flash of light is perceived before the 
eyes, corresponding with the shock. This 
phenomenon may be more faintly observed, 
by placing a piece of silver, as a shilling, be- 
tween the upper lip and the gum, and laying 
a piece of zinc at the same time upon the 
tongue: upon bringing the two metals in 
contact, a faint flash of light is perceived. 
It is singular, that this light is equally vivid 
in the dark with the strongest light, and 
whether the eyes be shut or open. 
Another variety of galvanic battery was 
also contrived by Volta. The pairs of 
plates were soldered to each end of a bit 
of wire, which was afterwards bent into an 
arch, so that the plates became parallel to 
each other. A number of glass cups were 
also provided, and filled with a solution of 
culinary salt. The glasses being arranged 
side by side, the metallic arcs were so 
placed, that the silver plate was immersed 
in one glass, and the zinc in another ; and 
also that a silver and zinc plate of different 
arcs should be placed in each glass. This 
arrangement was found to be similar to the 
pile, the water in the cups being substituted 
for the disks of cloth. 
Soon after the discovery of the pile, in 
1800, it was communicated by Volta him- 
self to the Royal Society, London. The first 
experiments made in this country upon the 
Voltaic pile, were made jointly by Messrs. 
Nicholson and Carlisle. After observing the 
phenomena already described by Volta, they 
observed an important fact which had es- 
caped the notice of that acute philosopher. 
When bringing the wire from the bottom of 
the pile, in contact with a drop of water at 
the top, they observed the disengagement 
of some gaseous substance, which had the 
smell of hydrogen. Supposing this effect 
to arise from the decomposition of the wa- 
ter, they caused the ends of two brass 
wires, coming from the two ends of the 
pile, to be immersed in water, so that a 
portion of that liquid might be exposed be- 
tween the wires. A disengagement of gas 
immediately took place from one of the 
wires, while the other became as quickly 
tarnished, and oxydated. The former ap- 
pearance took place at the silver end of the 
pile, the latter at the zinc end. They as- 
certained that the effect would not take 
place when the wires were placed far asun- 
der, and that the effect diminished gradually 
with the distance. They observed also, that 
when the tincture of litmus was used, instead 
of water, the liquid in the viciuity of 
the oxydated wire, being that connected 
with the zinc end, became red. When 
they made use of wire of platina instead of 
brass, they observed that the wire from the 
zinc end of the pile, which when of brass 
became oxydated, now gave out bubbles 
of gas, which they found to be oxygen. 
In short, they determined that the gases 
evolved were oxygen and hydrogen, and in 
proportions fit to constitute water. These 
discoveries established the chemical nature 
of the galvanic action in England; and they 
soon spread over all Europe. 
The above experiments were repeated 
by Mr. Cruickshank, of Woolwich. He 
employed a glass tube filled with water, 
having a cork at each end, through which 
wires of silver were passed, the points of 
which were separated from each other by 
a stratum of the liquid. Upon the wires 
being communicated with the two ends of 
the piles, the same appearances took place 
which were observed by Messrs. Nicholson 
and Carlisle : the silver wire, however, con- 
nected with the zinc-end of the pile, be- 
came oxydated, the oxide forming a white 
cloud round the wire: he also, instead of 
water, introduced into the tube an infusion 
of Brazil-wood. During the galvanic ac- 
tion, the colour in the vicinity of the wire 
of the zinc-end, became very pale, while 
that about the wire of the silver-end of the 
pile, appeared of a purple colour. When a 
metallic solution was placed in the tube, 
Mr. Cruickshank observed, that, instead of 
hydrogen gas being evolved from the wire, 
which connected the silver-end of the pile, 
