126 



ELECTROLYSIS. 



wire brush a part out of sight, or better, on a scratch brush 

 lathe. Should a piece become too rough, owing to an exag- 

 gerated strength of current, it can be improved by means of a 

 superficial polishing and put back in the bath. 



Hough and cheap articles are strung on a copper wire 

 and isolated from each other by means of large glass beads. 

 During the operation, which only lasts a few minutes, this chap- 

 let must be rocked to and fro without intermission. When the 

 objects are of very reduced sizes, as buttons, thimbles, screws, 

 rivets, &c., they are placed in an earthenware strainer, at the 

 bottom of which is a fine brass wire wound in a spiral shape ; 

 this wire is connected with the negative pole of the electric 

 source. These small objects are spread about the bottom of the 

 strainer so as not to form too thick a layer, and are continually 

 stirred under the action of the current in order to alter their 

 situation and position. If the bath is not very conductive, the 



FIG. 21. 





Nickel-plating of small objects. 



strainer may be held in the left hand, and the anode connected 

 to the positive pole in the right hand (Fig. 21), taking care not 

 to let the anode touch the objects. This operation succeeds 

 very well in a hot bath, in which case it is effected quicker than 



