ELECTRO-PLATING. 109 



262. A solution for gilding, is prepared 



How is the so- " _ 



lutionfor , by drying a solution of gold, at a moderate 

 heat > and dissolving it in cyanide of po- 

 tassium, as above described. The process 



for gilding, is in all respects the same as that for the 



deposition of silver. 



263. THE PROCESS. The battery and 



How is the sil- .... 



veriny process silvering solution being prepared, the cop- 

 conducted? ^ CQ ^ or ^j^ object to be silvered, is 



cleansed with potash, rubbed with chalk or rotten- 

 stone, and then attached to the wire proceeding from 

 the zinc. A silver coin is fastened to the other wire, 

 and immersed in the silvering solution ; acid is then 

 added to excite the battery, and the object to be silvered 

 is lastly immersed. It should be hung face to face with 

 the silver coin, and quite near to it, the two being kept 

 in their places by blocks placed across the tumbler, as 

 represented in the figure. The coin will receive a per- 

 ceptible coatingwithin a few minutes, and will be more 

 thickly covered, according to the time of immersion. 

 The deposit is hastened by keeping the solution mode- 

 rately warm. This is especially advantageous in the 

 commencement of the process. The newly plated sur- 

 face is without lustre, and requires burnishing after re- 

 moval from the solution. 



264. OBJECT OF THE SILVER COIN. The 



What is the 



object of the piece of silver is attached to the positive 

 wire, to maintain the strength of the solu- 

 tion. It is eaten away, and dissolved as fast as silver 

 is deposited on the objects connected with the negative 

 wire. The reason of this is, that the cyanogen of the 



