138 DEPOSITION OF BRONZE. 



layers, and the articles having the coating heated in charcoal, by 

 which means a brass of fair appearance was obtained, but the pro- 

 cess is attended with practical difficulty, and the product cannot be 

 called deposited brass. 



Deposition of Bronze. The following solutions of different metals 

 is given by BRUNEL, BISSON, and GAUGAIN, as being capable of 

 giving a deposit of bronze : 



50 parts Carbonate of Potash. 



2 Chloride of Copper. 



4 Sulphate of Zinc. 

 25 Nitrate of Ammonia. 



A bronze plate is used as the positive electrode. The deposit 

 given by this solution has been seen by Becquerel, who mentions 

 that it bears comparison with any ordinary bronze in appearance. 1 

 A solution of the above materials in the water strikes the ear as some- 

 what hypothetical : that a mixed solution of copper and zinc will 

 give, under certain conditions, a compound deposit, we know, and 

 also that, with a quantity of other salts present, will give peculiar 

 tints of colour, a circumstance which may be obtained without a 

 compound deposit. But the difficulty to be overcome is to proportion 

 the deposit of different metals, so that we may make up a solution 

 and battery that will deposit either Muntz's yellow metal, Stirling's 

 yellow metal, gun metal, or common brass, at pleasure ; and that we 

 may be able to produce compounds that are constant and unvarying : 

 so that, for example, we could deposit silver or gold of the standard 

 quality, all which, notwithstanding the many statements that have 

 been made in print, have yet to be discovered. 



We have thus given a brief review of the practical operations of 

 electro-metallurgy for the guidance of the student, who, as he pro- 

 ceeds, will find that the difficulties which at first beset his path will 

 gradually disappear : easier modifications of processes will suggest 

 themselves, as all operators cannot with equal facility follow the 

 same directions. New facts will reveal themselves to his inquiries ; 

 a wide field of interesting and profitable research will open up before 

 his mind ; and the steady and persevering experimenter and observer 

 will not fail to reap an abundant harvest of honour and gratification, 

 in being an instrument in promoting the knowledge of the working 

 of the laws of Nature. 



1 Progress of General Science, vol. ii. 



