GALVANISM. 



to support it on the sides with three pil- 

 lars 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 

 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, h owe ver, 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 srnell of hydrogen. Supposing 1 

 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 be 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 

 would 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 w r ire 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 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> 



