[mcintosh] 



ELECTROLYTIC PRECIPITATION OF ZINC 



117 



photographs, the numbers giving the amperes per square foot of 

 cathode surface. At lower densities the following results were ob- 

 tained. 



Current Density. 



Efficiency. 



In neutral or slightly acid solutions 25-30 amperes per square 

 foot is the optimum current density. 



U 



lOu 



96 



-So 



I 



92 



3D. 





y. 



'^dh 



^'ï'^<j Rai 

 of 



103 



Zl-^^d Sulphun, /led 



ôlZ/nc 



■I'it Z/nc 



^F 



fer-cem. Oulphunc ffc/d 



Current Densities in Acid Solutions. 



Two series of tests with acid electrolytes 4-4 and 3-0 per cent, 

 zinc were made. The first contained 2-4 per cent, acid, the second 

 4-5 per cent, and these were maintained constant to 0-2 per cent. 



