116 



ELECTRO-PLATING. 



being attached to the frame by a small rod K, figs. 44 and 46, moves 

 it up the inclined plane E, fig. 46, until the pin fixed in the wheel 

 A passes the end of the arm B. The frame then moving down the 

 incline E, brings B in gear with the next pin, and the same motion 



45 



TROUGH OR VAT 



again takes place, and so on successively. The speed is regulated 

 by the train moving in an endless screw fitted on the last wheel of 

 the arbour of a fan. The four holes in fig. 44 are for bolts or pil- 

 lars for screwing the two frames together. The frame has four 

 pullies and inclines, the latter adjustable to a greater or less degree 

 by the screw and grove at E. 



Deposit dissolving off. in Solution. In depositing any metal, but 

 more particularly such as require solutions having an excess of the 

 solvent, such as of cyanide of potassium in the depositing of gold 

 and silver, care should be taken that nothing stops the current of 

 electricity suddenly, while the article being deposited upon remains 

 in the solution, otherwise the metal deposited will speedily dissolve 

 off. This we have often experienced, and many others have no 

 doubt done the same. Indeed, we have seen a beautiful deposit 

 going on, and left the operation with great hope of excellent results, 

 but on returning shortly after have found the whole dissolved off. 

 And often, when the process was apparently going on well, and the 

 articles had been in the solution the usual time to receive a fair 

 coating of metal, upon taking them out and weighing them, there 



