The pile, thus formed, was found to unite the effects of as many pairs of plates as might be employed. Previously to 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 lit tle or no shock was perceived, when the hands, or other parts applied, were not previously moistened. It was also ob served 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 knuc kle ; but if a spoon, or other metallic sub stance, were grasped in moistened 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 vi vid flash of light is perceived before the eyes, corresponding with the shock. This phenomena may be more faintly observ ed, by placing a piece of silver, as a shil ling, between 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 were afterwards bent into an arch, so that the plates became paral lel to each other. A number of glass cups were also provided, and filled with a so lution of culinary salt. The glasses being arranged side by side, the metallic arcs were so placed, that the silver plate was immersed into 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 de scribed by Volta, they observed an im portant fact, which had escaped the no tice 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 'disengage ment of some gaseous substance, which had the smell of hydrogen. Supposing
this effect to arise from the decomposition of the water, 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 he exposed between 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 appearance took place at the sil ver end of the pile, the latter at the zinc end. They ascertained, that the effect not take place when the wires were placed far asunder, and that the ef fect diminished gradually with the dis tance. They observed, also, that when the tincture of litmus was used, instead of water, the liquid in the vicinity 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 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 hy drogen, and in proportions fit to consti tute 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. Cruikshank, 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, connected with the zinc end of the pile, became oxydated, the oxide forming a white cloud round the wire : he also, instead of water, introduced into the tube an infusion of Brazil wood. Dur ing the galvanic action, the colour in the vicinity of the wire of the zinc end be came very pale, while that about the wire of the silver end of the pile appeared of a purple colour. When a metallic solu tion was placed in the tube, Mr. Cruick shank observed, that, instead of hydrogen gas being evolved from the wire, which connected the silver end of the pile, as in the former experiments, the metal be came revived.
He next causelthe 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, the gold was dis solved by the oxy-muriatic acid. Aqua ammonia being operated upon in a simi lar way, both the water and the alkali un derwent decomposition, producing the gases of hydrogen, nitrogen, and oxygen.