2 HISTORY OF ELECTRO-METALLURGY. 



Chemical Decompositions by the Pile. This discovery placed in 



the hands of the philosopher an instrument by which he could make 

 such investigations as had never previously been conceived to be 

 possible. NICHOLSON, for example, effected the decomposition of 

 water and of several metallic salts ; and observed, as a general rule, 

 that in the decomposition of the latter the metal of the salt was re- 

 duced upon the zinc terminal of the pile. 



First Battery. CRUIKSHANKS, of Woolwich, with a V16W to facili- 

 tate the construction of the pile, employed square plates of copper 

 and zinc, soldered together two and two : these were cemented, by 

 means of pitch, into a wooden trough, at the distance of about a 

 quarter of an inch from each other, and so arranged that the zinc 

 plates all faced one end of the trough, and the copper plates the 

 other end. The spaces or cells between every pair of plates were 

 filled with a solution of common salt, or a mixture of acid and 

 water, which produced the same effect as the moist cards in the pile. 

 The trough thus charged with it its metals and solution acted the 

 same part as the voltaic pile. This was the first of those instruments 

 now so well-known as the "galvanic battery" 



Decomposition by the Battery, and its Application. CRUIKSHANKS 



attached a silver wire to each terminal of his battery, and the other 

 ends of these wires he placed in a glass tube. When this tube was 

 filled with a solution of acetate of lead, and the electric current was 

 allowed to pass through it for some time, metallic lead was found 

 deposited upon the wire attached to the zinc terminal of the battery. 

 Solutions of sulphate of copper, nitrate of silver, and several other salts, 

 were tried with similar results. The metals, as Cruikshanks expressed 

 it, were " revived" and that so completely, as to suggest to him the 

 application of the battery to the analysis of minerals. While Cruik- 

 shanks, Nicholson, and several other gentlemen in this country, were 

 making investigations and applications of voltaic electricity, upon 

 the Continent, BRUGNATELLI, FOURCROY, VAUQUELIN, and THENARD, 

 were making similar investigations, and obtaining similar results. 1 



Deposition of Metals upon others. Brugnatelli, in his Annals 

 of Chemistry, gives a long list of experiments on the decomposition 

 of salts by the pile. He observed the transfer of the elements of a 

 decomposed compound from one pole to another that silver, when 

 deposited upon platinum, preserved all its metallic brightness and 

 that, when copper or zinc were used in connection with the silver 

 terminal, or positive pole, of the pile for decomposing salts, these 

 metals were dissolved, and deposited upon the negative pole. The 

 researches of Fourcroy, Vauquelin, and Thenard, gave the same 

 results. 



1 Wilkinson, Elements of Galvanism, vol. ii. 1801. 



