150 



KOLLOCK-SMITH — ELECTRO-ANALYSIS. 



[April i 3) 



experiments made to determine the rate of deposition with a lower 

 current (1-2.5 amperes and 10-9 volts) while the other conditions 



15 Minutes. 

 Curve 10. Iron — 1 to 2.5 Amperes, 10-9 volts. 



remained as above, gave the following results which appear in 

 Curve 10. 



In 2.5 minutes o. 1141 gram of iron was deposited. 



" 5 " 0.1787 " " » " 



" 7.5 " 0.1945 " " " " 



" 10 " 0.1950 " " " " " 



When the residue was tested with potassium sulphocyanide no 

 iron was detected. By the addition of 3 drops (40 drops = 1 c.c.) 

 of sulphuric acid and using a higher current (3.5 amperes) in 10 

 minutes a faint reaction for iron was observed indicating that the 

 acid has some retarding influence. In fifteen minutes under these 

 conditions the iron had completely separated. By using a higher 

 current 3 amperes and 9 volts under the same condition all the 

 iron was deposited in ten minutes. 



University of Pennsylvania. 



