ELECTRO-METALLURGY. 



HISTORY OF THE ART. 



IN reviewing the rise and progress of any discovery in the arts and 

 sciences, particularly of one connected with chemistry, there are two 

 circumstances which almost invariably demand especial notice. The 

 FIRST is, that the discovery has been the result of accidental obser- 

 vation a fact eliminated during investigations undertaken for other 

 purposes rather than the result of a direct endeavour to make the 

 discovery. The SECOND is, that, after the discovery has been made 

 known, it is found that many previously published experiments 

 exhibited results which bore more or less directly upon the subse- 

 quent discovery, and which are consequently sometimes cited to 

 detract from the merit of the discoverer, and the originality and value 

 of his discovery. The following historical sketch will show that these 

 observations directly apply to the discovery of the art of Electro- 

 Metallurgy : 



Voiia's Discovery. At the beginning of the year 1800, Professor 

 YOLTA invented the apparatus which has been named after him the 

 Voltaic Pile. As originally constructed by Volta, it consisted of an 

 equal number of round pieces of zinc, silver, and pasteboard the 

 zinc and silver pieces being each about the size of a penny, and 

 those of pasteboard a little smaller : the pasteboard pieces were 

 soaked in a solution of common salt, and then with the metals were 

 piled in the following manner : zinc, silver, pasteboard ; zinc, silver, 

 pasteboard ; and so on, in the same order, till all the pieces, amount- 

 ing to upwards of a hundred, were piled upon each other, the upper- 

 most plate being of silver, and, as already stated, the undermost of 

 zinc ; these exterior plates, to each of which a wire was attached, 

 form the terminals or poles of the pile, an instrument which pro- 

 duced the phenomena of an ordinary battery. 



