SO HISTORY OF GALVANISM. 



through the interrupted circuit, in which the 

 tube was filled with the solution of acetate of lead, 

 when it was observed that the lead was sepa- 

 rated in the metallic state, and deposited at the 

 Metais re- end of the silver wire, or the wire connected with 

 metallic so- the silver end of the pile, in the form of fine 

 needles. Experiments were afterwards made upon 

 the solutions of sulphate of copper and nitrate of 

 silver : in this last case, he observes, " the metal 

 shot into fine needles, like crystals articulated or 

 jointed to each other, as in the arbor Diance" 

 He also succeeded in decomposing some of the 

 neutral salts.* 



In a second memoir, Cruickshanks paid more 

 particular attention to the nature of the gases emit- 

 ted in the interrupted circuit to the effects of 

 different kinds of wires and to the influence of 

 the fluid medium upon the decomposition of the 

 Concludes water. Some of his most important conclusions 

 gen is y ai- ~ are, that from the wire connected with the silver 

 te^from 1 '" or c PP er en ^ of the pile, whatever be its compo- 

 ooe wire, s ition, if it terminate in water, the eras emitted is 



from the 



other oxy- chiefly hydrogen ; if it terminate in a metallic 

 wireoxi- solution, the metal is reduced, and is deposited at 

 the end of the wire. When the wire connected 

 with the zinc end is formed of a perfect metal, 

 nearly pure oxygen is disengaged : when of an 

 oxidable metal, it is partly oxidated and partly 

 dissolved, and only a small quantity of oxygen is 



* Nicholson's Journ. 4?to. iv. 187. 

 1 



