KOLLOCK-SMITH — ELECTRO-ANALYSIS. 



145 



nickel was found in the liquid after seven minutes. The amalgam 

 was very bright and of the consistency of soft dough, when one 

 gram of nickel was combined with the usual quantity of mercury 

 (40 grams). 



Curve 6. Nickel — 2. 5 Amperes, 

 6 volts. 



Curve 7. 



volts. 



Cobalt — 5 Amperes, 5 



Cobalt. 

 This metal does not appear to enter the mercury with the same 

 rapidity as nickel under similar conditions. The last minute traces 

 are more difficult to remove. Various conditions were used. When 

 no sulphuric acid was added the current was at first low, but it 

 rapidly rose as the decomposition proceeded. The conditions, 

 giving the total cobalt in the least time, were the following : 10 

 c.c. of solution, containing 0.3535 g ram of cobalt ; 0.25 c.c. of 

 sulphuric acid and a current of 5 amperes with a pressure of 6 

 volts. The speed of the anode was 1,200 revolutions per minute. 

 The solution became colorless in seven minutes, but ten minutes 

 appeared to be necessary for the removal of the last traces of the 



