Warwick.] [Nov. 6, 



The distance between the poles was 2.9 cm., area of electrodes (3.5 

 cm. X 3.8 cm.) X 2, current strength 7.5 c.c. OH gas per minute. The 

 ratio of increase was : (20-40) .0060 grams, (40-60Q) .0073 grams, 

 (600-80) .0083 grams. A comparison between the two series of results 

 would indicate that the presence of dilute free acid in moderate quantity 

 exercises no material influence on the amount of metal deposited, even at 

 elevated temperatures. 



III. THE INFLUENCE OF POLE SEPARATION UPON THE PRECIPITATION 



OF COPPER. 



The area of the electrodes was (3.8 cm. X 3.48 cm.) X 2, free acid pres- 

 ent 10 c.c. (1) was slightly spongy. (7) was very close to the edge of 

 the dish. The diminution was (1-2) .0027 grams, (2-3) .0013 grams, 

 (3-4) .0009 grams, (4-5) .0006 grams, (5-6) .0005 grams. The current gave 

 1.75 c.c. OH gas per minute. 



The foregoing experiments were performed in a crystallizing dish 15.2 

 cm. by 7.6 cm., with a capacity of 900 c.c. In the following series the 

 determinations took place in a beaker 10cm. in height by 7.6cm. in 

 diameter. 



Distance of 



electrodes. 



cm. 



1.58 



8.16 



4.75 



6.33 



The current gave 1.75 c.c. oxyhydrogen gas per minute, area of 

 electrodes (3.8 cm. X 3.16 cm.) x 2, free acid present 5 c.c. The diminu- 

 tion was (1-2) .0054 grams, (2-3) .0040 grams, (3-4) .0036 grams. In 

 both series the rate of diminution rapidly lessened as the distance between 

 the electrodes increased. ,.".' 



Experiments made under conditions similar to the above, except that 

 no free acid was present, were failures, the deposits being exceedingly 

 spongy. 



