1905.] 



KOLLOCK-SMITH — ELECTRO-ANALYSIS. 



141 



15 minutes. The following conditions were employed : Total vol- 

 ume 15 c.c, sulphuric acid 0.4 c.c, current strength 2 amperes, 

 pressure 7 volts, speed of anode, 500 revolutions per minute. 



In 5 minutes 0.1860 gram of zinc was deposited. 

 " 10 " 0.1998 " " " i( " 



" 15 " 0.2020 " " " " " 



Double the quantity of zinc mentioned above was dissolved in 

 15 c.c. To this was added .25 c.c. of concentrated sulphuric acid, 

 the anode was rotated at the rate of 800 revolutions per minute and 

 the solution electrolyzed. In thirty minutes the zinc was com- 

 pletely deposited, using a current of 1.5 amperes and 10 volts. 



Curve 2. Zinc— 2 Amperes, 7 volts. 



Curve 3. Zinc-2 Amperes, 6 volts 



In 10 minutes 0.3701 gram was deposited. 

 " 15 " 0.3997 " " 

 " 20 " 0.4011 " " " 



" 30 " 0.4058 " 



Curve 3 was drawn from these results. 



The same mass of zinc in twenty cubic centimeters was electro- 

 lyzed with a current of 2 amperes and 6 volts, other conditions 

 being identical. 



