NICKEL-PLATING. 103 



ot electro-deposition some very interesting notes ; Mr. Watt, of 

 New York, who undertook to propagate Mr. Adams's processes ; 

 Mr. Urqnhart, the English author the most extensively consulted 

 in all questions of electro-chemistry ; Messrs. Neumann, Schwarz 

 and Weil, who have established a model works at Freiburg ; 

 Mr. Elmore, the specialist manufacturer of London, &c.; without 

 forgetting Messrs. Gaiffe, Koseleur, and Meidinger, whose works 

 we have also consulted. 



We have left out no interesting prescription, whatever 

 country they might originate from, as we consider that the 

 best executed work is the privilege of no particular nation, and 

 that in the matter of nickel-plating as well as in every other 

 industry, excellent methods are to be found everywhere. 



A good nickeling must be white and solid. These qualities 

 are dependent upon the three following conditions : 1st, a 

 rational preparation of the baths and the purity of the salt of 

 nickel used ; 2nd, a suitable intensity and electromotive force 

 of the electric current; 3rd, a judicious treatment of the pieces 

 to be nickeled, before, during, and after their immersion in the 

 chemical bath. 



PREPARATION OF THE BATH FOR NICKEL-PLATING. The 

 purity of the salt of nickel is the primordial condition for the 

 preparation of a bath giving good deposits. It is difficult to 

 prepare salts of nickel perfectly free from foreign substances, 

 such as copper, arsenic, cobalt, &c., but they, however, exist, 

 and can be obtained, and the operator must not be induced to 

 buy cheap material ; he must take his supply from well-known 

 dealers, and on the least doubt arising about the whiteness or 

 solidity of the deposit, have his salts and acids submitted to an 

 analytical chemist. 



The selection of the water itself is of very important 

 moment, and must be effected with judgment. Waters from 

 rivers, sources, wells, are very often defective, because they 

 contain, in solution, iron, iodine, calcic sulphates, and car- 

 bonates, &c. ; the best plan is to use distilled water only. In 

 the case of large baths, where the expenditure due to the use 

 of distilled water might prove considerable, rain water may 

 be substituted. The first water should not be collected, as it 



