PRACTICAL INSTRUCTIONS IN PLATING. 



Ill 



frames of wood, are now generally fixed upon light iron frames, 

 because these are not effected by the solution : two battery troughs 

 are arranged as seen in fig. 41, consisting of 6 batteries of 3 pair 

 intensity. The zinc plates immersed in the acid measure 6 inches 

 by 7 inches, the exposed surfaces of which measure 84 square 

 inches : these multiplied by 6 give 504 square inches, from which 

 electricity is disengaged. The surface of the silver electrodes 

 exposed to the articles receiving the deposit vary from 3000 to 4000 

 square inches of surface. 



The following figure, with explanation, will illustrate these 

 observations: 



A, Vat or vessel containing the solution ; B, Battery with zinc 

 pole Z, connected with rods RE ; and copper pole C, connected with 

 the metallic sheets PP, in the solution, by means of the copper slip 

 F ; DD, are articles suspended in the solution by wires from the 

 rods RR ; S, the solution. So soon as the articles, which are con- 

 nected with the negative pole of the battery, and the metallic sheets 

 connected with the positive pole, are both immersed in the solution, 

 the galvanic circuit is completed. 



In most plating establishments the batteries are now placed out- 



