14G 



KOLLOCK-SMITH — ELECTRO-ANALYSIS. 



[April 13, 



metal. On using the same amount of cobalt in a volume of five 

 cubic centimeters, other conditions remaining unchanged, all of the 

 metal separated in seven minutes, thus : 



In I minute 0. 1197 gram, of cobalt was deposited. 

 3 " 0.2930 " " " 



5 " 0.3300 " " " 



6 " 0.3520 " " " 



7 " 0.3535 " » " 

 10 " 0.3530 " " " 



The curve (7) was constructed from these results. 

 Cobalt. 



Chromium. 

 A solution of chromium sulphate was electrolyzed with currents 

 varying from 1 to 4 amperes and 7 to 12 volts and with a varying 

 quantity of sulphuric acid. It was found by Myers that the addi- 

 tion of the acid was necessary, otherwise, there was a separation of 

 the oxide of chromium throughout the liquid ; but too much acid 

 retards or entirely prevents the decomposition. When 10 drops 

 {40 drops = 1 c.c.) were added and a current of 2.5 amperes and 

 6 volts applied one half hour was necessary to deposit o. 23 gram of 

 chromium. With 0.5 c.c. of acid and a current of 5 amperes and 

 4 volts the solution at the end of 60 minutes did not appear 

 to have lost its color. Experiments were then made to learn how 



