338 



Common Science 



during the experiment. The copper should be entirely 

 covered by the nickel solution, but should not touch 

 the bottom or sides of the bowl. Pour the cleansing 

 solution from the evaporating dish back into the bottle. 

 Suspend the nickel, in the same way as the copper, from 

 the positive wire crossing the bowl. When set up, the 

 apparatus should appear as shown in Figure 178. 



Turn on the electricity. If the copper becomes black 

 instead of silvery, clean it again in the cleansing solu- 

 tion, and move the two bare wires much farther apart, 

 - practically the full width of the bowl. If the copper 



FIG. 178. Plating the cupper by electricity. 



