ELECTRO-PLATING. 107 



goes to the negative, and the oxygen, chlorine, or 

 cyanogen, to the positive. But the metals, when sepa- 

 rated from their combinations, being solid bodies, can- 

 not escape. They collect on the negative electrode, in- 

 stead. If this be attached to a brass spoon or fork, or 

 any other object it is desired to plate, the spoon be- 

 comes itself the electrode, and the metal is deposited 

 upon it as long as the action of the battery continues. 

 At the same time, the oxygen, or other negative ele- 

 ment, goes to the positive electrode, generally cor- 

 roding it, instead of passing off as gas. 



257 . SILVERING APPARATUS. The re- 



W hat appara- . 



tue is required quirements for electro-silvering or gilding, 



are first > a batter Y of somewhat different 



form from that already described, though 

 precisely the same in principle ; second, an acid to ex- 

 cite it ; and third, a solution containing gold or silver. 

 These will be described in turn. 



258. A convenient form of the 

 apparatus is represented in the fig'i 

 are, and may be prepared from 

 sheet zinc and copper in a few mo- -^ 

 ments. It consists of a bent strip 



of the former metal, with a strip of copper 

 thc fastened between the two portions. The 



metals should be within an eighth of an 

 inch of each other, but without contact. To secure 

 this, they are tied together with thread, bits of wood or 

 cotton cloth being previously interposed. Copper 

 wires being attached to the zinc and copper, as rep- 

 resented in the figure, the apparatus is placed in a com- 

 mon tumbler, and the battery is complete. 



