1891. J 111 [Warwick. 



I. Influence of Dilution upon the Precipitation of Cadmium. 



In (1) and (2) no free acid was added, and in (3) only .5 c.c. was pres- 

 ent ; all three were failures. The amount of acid was then increased to 

 5 c.c, and the experiment repeated, all the other conditions remaining 

 the same. The deposit was adherent and compact. The poles were 3.16 

 cm. apart, and had an area of (2.85 cm. X 3.8 cm.) x 2. 



II. Influence of Temperature upon the Precipitation of 



Cadmium. 



(2) was very spongy and -was covered with a white gelatinous deposit 

 resembling cadmium hydrate. The amount of cadmium was then dimin- 

 ished more than half, while the amount of formic acid present was in- 

 creased to 25 c.c. (5) and (6) were somewhat spong} r but adherent. The 

 increase was (200-40°) .0022 grams, (400-60°) .0100 grams, (600-80) .0047 

 grams. The amount of metal deposited increased with rise of temperature, 

 being greatest at 80°, but the greatest ratio of increase was at 60°, being 

 almost five times greater than at 40°, and more than twice as great as at 

 80°. These results were so different from those obtained with copper 

 that a second series of determinations was made, in wdiich the amount of 

 cadmium in the solution was reduced still more in order to insure a com- 

 pact deposit at the higher temperatures. The results which, were in close 

 accord with those above are as follows : 



