408 



Mr. T. Gray on the Electrolysis 



These experiments show clearly a gradual increase in the ratio 

 with successive experiments, and that in a more marked de- 

 gree with the small current-density than with the large. 



Omitting the results of experiments 2 to 6, the average 

 ratio for the two current-densities here used are *2940 and 

 '2931, and the ratio of these two numbers will be found to be 

 in good agreement with the results of special experiments on 

 the effect of size of plate given in Table V. and illustrated in 

 curve 13. 



















"3540 

 •3520 















































o 201 400 600 800 



Abscissae give area of cathode in square centims. per ampere. 



Effect of Size of Plate or Current-Density. — The two ex- 

 periments on the effect of the density of the current at the 

 cathode, the results of which are given in Table V. and illus- 

 trated in curve 13, were made on the 25th and 28th of June 

 respectively; the current, as measured by one of Sir William 

 Thomson's galvanometers, was about *0997 ampere and was 

 continued for three hours. The first column gives the area 

 of the deposit, the second and third the amount of copper 

 deposited. 



Table V. 



Area of plate 

 in sq. cms. 



Weight of deposit 



in grammes 

 (first experiment). 



Weight of deposit 



in grammes 



(second expt.). 



3 



5 

 11 



18-5 



36 



73 



•3534 

 •3530 

 •3528 

 •3526 

 •3524 

 •3503 



•3533 

 •3529 

 •3530 

 •3527 

 •3521 

 •3502 



The results given in Table IV. indicate a slightly greater 

 difference between the results obtained with a current-density 

 of a fiftieth of an ampere and those obtained with a two 

 hundred and fortieth of an ampere per square centimetre of 



