Warwick.] [Nov. 6, 



gray and adherent on the sides and bottom, but rather spongy at the 

 periphery. Around the top of the crucible the metal was black in color. 

 The final determinations were accurate but required the greatest care to 

 avoid detaching loose particles of metal. 



The deposit was not regular, the bottom of the crucible being more or 

 less free from zinc on account of the accumulation of gas. The time of 

 deposition averaged sixteen hours. Such currents as sufficed to separate 

 copper were unsatisfactory, even when the electrodes were brought in 

 close contact. In the determinations that were satisfactory, the current 

 strength varied from 1.6 1.8 HO gas per minute, and the poles were 

 close together. 



CADMIUM (DETERMINED AS CoO). 



Cadmium formate Cadmium Cadmium in. Difference in percentage 

 taken. by theory. CdO found. from theory. 



(1) .4234 .1988 .1983 .25$ 



(2) .4224 .1988 .1982 .30 



Both results are somewhat too low, possibly owing to reduction of the 

 oxicle to metal and consequent loss by volatilization. 



CADMIUM (DETERMINED ELECTROLYTICALLY). 



Time in Differ' ce in percent 

 hours. from theoretical. 



+ .20 



.30 



.40 



.16 



+ .10 

 + .09 



.19 



The dish was used as the negative electrode, the spiral as the positive, 

 except (1), in which the cadmium was deposited on the crucible, the dish 

 serving as the anode. The distance between the poles was 2.5 cm. The 

 variations in the conditions of the experiments noted above caused no 

 noticeable difference in the results. The deposit was not apparently 

 oxidized by moderate warming. Current 1.25 to 1.5 c.c. HO gas per 

 minute. 



The solutions were tested for cadmium at the conclusion of each experi- 

 ment, but none was found, proving that the metal was completely de- 

 posited. It formed a firm and adherent coating, white in color, with a 

 bright metallic lustre. 



