HISTOEY OF ELECTRO-METALLURGY. 3 



Gilding. In 1805, Brugnatelli, in a letter to VAN MONS, men- 

 tions, among other scientific facts, that " he had gilt in a complete 

 manner two large silver medals, by bringing them, by means of a 

 steel wire, into communication with the negative pole of a voltaic 

 pile, and keeping them one after the other immersed in ammoniuret 

 of gold newly made and well saturated." 1 



Early Opinions concerning Electro-Decomposition. The above 



few instances are selected from a host of a similar kind upon electro- 

 decomposition, to show that the fact of the deposition of metals by 

 an electric current was familiar to philosophers at this early stage of 

 the history of galvanism ; that, nevertheless, the phenomenon was 

 never thought of further than as a curious action of electricity when 

 passing through a solution containing metals ; and that although 

 these effects were produced again and again, it was only to illustrate 

 certain speculative views respecting the electric fluid. Brugnatelli 

 had formed an idea that the electric fluid had some relations to an 

 acid which he called the electric acid, and he therefore viewed the 

 decomposition of solutions, and the obtaining of the metal, which he 

 termed an electrate, as the result of the combination of this electric 

 acid with the metal of the solution. In one of his memoirs upon this 

 subject, he says " Gold and platinum are not sensibly altered by 

 the electric matter which passes through them, though it often hap- 

 pens that the electric current deposits on gold a stratum of zinc, 

 copper, mercury, or silver, according to whichever of these metallic 

 bodies it traverses." 2 In the same paper it is several times stated 

 that gold and platina do not seem sensibly affected by the electric 

 acid. And, when he communicated the above experiment of gilding 

 the two medals, his object was to show that he had now found that 

 the electric acid had also the power of acting upon gold ; and the 

 publication of these results and observations excited no other idea in 

 the minds of philosophers of that period than that they were mere 

 scientific curiosities. The Editor of the Philosophical Magazine 

 appended the following note to the extract already quoted : " The 

 result here detailed reminds me of one, somewhat similar, which took 

 place during some experiments performed some years ago in the 

 Askesian Eooms. Some gold leaf was put loose upon a new piece of 

 copper coin, which was then brought into the circuit of the pile. A 

 part of the gold was inflamed, and other portions adhered to the sur- 

 face of the copper, as completely as if they had been attached by any 

 common gilding process." 3 



HOW these Results affect the Discovery. We have been particular 



1 Phil. Magazine, 1805. 



2 Brugnatelli, Annals of Chemistry, vol. xviii.. and Wilkinson, vol. ii. 

 8 Phil! Mag., 1805. 



