Manchester Memoirs, Vol. LX. {No. 11). 



Plate. 



Zinc before. 



Zinc after. 



Copper before. 



Copper after. 



Platinum before. 



Platinum after. 



Microphotographs of metal cathode plates before and after electrolysis 

 with a current density of I ampere per sq. cm. for two hours. Magnifi- 

 cation 320 diameters. 



