20 



HISTORY OF ELECTRO-METALLURGY. 



powder, when the current of 

 electricity is so strong, in rela- 

 tion to the strength of the solu- 

 tion, that hydrogen is evolved 

 from the negative plate of the 

 decomposition cell. 



"Law II. Every metal is 

 thrown down in a crystalline 

 state, when there is no evolution 

 of gas from the negative plate, 

 or no tendency thereto. 



"Law III. Metals are re- 

 duced in the reguline state, when 

 the quantity of electricity, in 

 relation to the strength of the 

 solution, is insufficient to cause 

 the production of hydrogen in 

 the negative plate of the decom- 

 position trough, and yet the 

 quantity of electricity very nearly 

 suffices, to induce that pheno- 

 menon." 



pended entirely on the weakness 

 or intensity of the electro-che- 

 mical action, which I knew I had 

 in my power to regulate at plea- 

 sure, by the thickness of the 

 intervening wall of plaster of 

 Paris, and by the coarseness or 

 fineness of the material. I made 

 three similar experiments, alter- 

 ing the texture and thickness 

 each time, by which I ascer- 

 tained, that if the partitions were 

 thin and coarse, the metallic de- 

 position proceeded with great 

 rapidity, but the crystals were 

 friable and easily separated; on 

 the other hand, if I made them 

 thicker, and of a little finer ma- 

 terial, the action was slower, but 

 the metallic deposition was as 

 solid and ductile as copper formed 

 by the usual methods. Indeed, 

 when the action was exceedingly 

 slow, I have had a metallic depo- 

 sition much harder than common 

 sheet copper, but more brittle." 



The identity of these deductions or laws requires no comment ; 

 and, comparing the circumstances of the one having nothing but the 

 rude apparatus of a new-born art suggested by himself, to that of 

 the other, enjoying the advantage of eighteen months' improvements, 

 Mr. Spencer is astonishingly correct, and his name should be identified 

 with the discovery of these laws. The claim of originality involved 

 in the inference drawn by Mr. Smee, though formidable at first sight, 

 is, nevertheless, without foundation. Mr. Smee says " These laws 

 appear to me at once to raise the isolated facts known as the electro- 

 type into a science, and to add electro-metallurgy as an auxiliary to 

 the noble arts of this country." Unfortunately for the validity of Mr. 

 Smee's claim, patents were taken out long previous, both in England 

 and France, for the application of the electro-depositions to the arts. 

 And Messrs. Elkington's patent for silvering and gilding by this pro- 

 cess a patent which has not yet been superseded was not only 

 published in full detail, but was in extensive operation months before 

 the publication of Mr. Smee's book. Nevertheless, the publication 

 of Mr. Smee's book did good service to the art of electrotyping ; and 



