NICKEL-PLATING. 141 



double salts, he uses single salts of nickel, and adds to the solution 

 a certain quantity of benzoic acid. 



He recommends the two following formulae : 



1. Sulphate of nickel 270 grammes. 



Citrate of nickel 200 



Benzoic acid .. 70 



Distilled water 10 litres. 



2. Chloride of nickel 140 grammes. 



Citrate of nickel 140 



Acetate of nickel 140 



Phosphate of nickel 140 



Benzoic acid 70 



Distilled water 10 litres. 



Benzoic acid being scarcely soluble in water, the salts of 

 nickel should be heated in water, and when the liquid is at 

 boiling point, add the acid, which combines with the mixture 

 better than with water alone. 



