342 GALVANISM. 



! transfer appear to Ritter, that at that time he regarded his experiment as pro- 

 j ving that one portion of the water acted on was wholly converted into oxygen, 

 > and the other portion into hydrogen.* 



This point was the first to attract the attention of Davy, and it occurred to 

 him to try if decomposition could be produced in quantities of water contained 

 in separate vessels united by a conducting substance, placing the positive wire 

 in one vessel and the negative in the other. For this purpose, the positive and 

 negative wires were immersed in two separate glasses of pure water. So long 

 as the glasses remained unconnected, no effect was produced ; but when Davy 

 put a finger of the right hand in one glass and of the left hand in the other, 

 decomposition was immediately manifested. The same experiment was after- 

 ward repeated, making the communication between the two glasses by a chain 

 of three persons. If any material principle passed between the wires in these 

 cases, it must have been transmitted through the bodies of the persons forming 

 the line of communication between the glasses. 



The use of the living animal body as a line of communication being incon- 

 venient where experiments of long continuance were desired, Davy substituted 

 fresh muscular animal fibre, the conducting power of which, though inferior to 

 that of the living animal, was sufficient. When the two glasses were con- 

 nected by this substance, decomposition accordingly went on as before, but 

 more slowly. 



To ascertain whether metallic communication between the liquid decompo- 

 sed and the pile was essential, -he now placed lines of muscular fibre between 

 the ends of the pile and the glasses of water respectively, and at the same 

 time connected the two glasses with each other by means of a metallic wire. 

 He was surprised to find oxygen evolved in the negative, and hydrogen in the 

 positive glass, contrary to what had occurred when the pile was connected 

 with the glasses by wires. In none of these cases did he observe the disen- 

 gagement of gas either from the muscular fibre or from the living hand immer- 

 sed in the water. 



In October, 1800, after many experiments on the chemical effects of the 

 pile, Davy commenced an investigation of the relation which its power had to 

 the chemical action of the liquid conductor on the more oxydable (*" its metal- 

 lic elements. The influence of chemical decomposition in evolving the Voltaic 

 electricity originally maintained by Fabroni, was again brought under inquiry 

 by Colonel Haldane. Davy showed that at common temperatures zinc, con- 

 nected with silver, suffers no oxydation in water which is well purged of air 

 and free from acids ; and that with such water as a liquid conductor, the pile 

 is incapable of evolving any quantity of electricity which can be rendered sen- 

 sible either by the shock or by the decomposition of water ; but that if the 

 water used as a liquid conductor hold in combination oxygen or acid, then oxy- 

 dation of the zinc takes place, and electricity is sensibly evolved. In fine, he 

 concluded that the power of the pile appeared to be, in great measure, propor- 

 tional to the power of the liquid between the plates to oxydate the zinc.f 



He inferred from these results that although the exact iode of operation 

 could not be accounted for, the oxydation of the zinc in the pile, and the chem- 

 ical changes connected with it, were somehow the cause of its electrical effects. 



To ascertain whether a liquid solution capable of conducting the electric cur 

 rent between the positive and negative wires of a Voltaic pile, but not capable 

 of producing any chemical action on its metallic elements, would, when used 

 between its plates, evolve electricity, Davy constructed a pile in which the li- 

 quid was a solution of sulphuret of strontia. When the current from an active 

 pile was transmitted through the liquid, the shock was as sensible as if the 



* Nicholson's Journal, vol. iv., p. 512. t Nicholson's Journal, vol. iv., p. 337. 



