at the Electrodes in a Solution. 



69 



A New Method for the Determination of the Diffusion- 



Coefficient of Pure Copper Sulphate. 



A second series of experiments was performed in order to 

 study the behaviour of a pure copper-sulphate solution after 

 the concentration of the copper at the electrode had gone 

 down to zero. 



Table II. 

 Solution A, see Table I. Experiments in Apparatus 1. 



Experimental Values. 





Current 



Surface 





in 



of 



No. 



rnilli- 



electrode 





amps. 



in sq. cm. 



1 ... 



933 



13-53 



2 



181 



1676 



3 ... 



205 



13-53 



4 ... 



409 



13-53 



5 ... 



51-6 



13-53 



6 ... 



52 8 



1353 



7 ... 



574 



1353 



8 ... 



78-2 



1353 



Current- 

 density in 

 milliamps. 



690 

 1-081 

 1-515 

 302 



3-88 



3-905 



4-24 



5-78 



Time, 

 observed 



in 

 seconds. 



2480 



1010 



510 



110 



75 

 73 

 62 

 28 



Temp. 

 i» °C. 



16 

 14 

 17 

 15 

 13 

 14 

 15 

 13 



Time 

 cor- | 

 rected 

 to 18° 



2617 



1128 



524 



119 



86 

 81 

 67 

 32 



Theoretical Values. 



t ace. 

 to eq. 16 



t= 



]246 



2618 



1068 



543 



137 



85 

 82 

 69 

 37 



t mini- 



£ maxi- 



mum. 



mum. 



836 



1609 



i == — 



P 



r 



1756 



3380 



717 



1377 



364 



701 



92 



176 



57 



107 



55 



105 



47 



90 



25 



48 



Table III. 



Solution B, see Table I. Experiments in Apparatus 2. 

 Surface of Cathode *699 sq. centim. 



Experimental Values. 



Theoretical Values. 







Current- 



Time 





Time 



1 ace. 



t mini- 



t maxi- 



No. 



Current 



density in 



observed 



Temp. 



cor- 



to eq. 16. 



mum. 



mum. 



milliamps. 



milliamps. 



in 



seconds. 



in°C. 



rected 

 to 18°. 



2716 



1773 



330 ' 



cm. 2 



1 ... 



0-776 



1111 



2025 



12-4 



2371 



i 2201 



1437 



2698 



2 



1-131 



1-617 



945 



138 



1060 



1038 



678 



1274 



3 ... 



1-183 



1-936 



630 



13-6 



711 



725 



473 



889 



4 ... 



2-09 



299 



290 



13-8 



318 



304 



199 



372 



5 ... 



2-50 



358 



170 



14-8 



185 



212 



138 



260 



6 ... 



2-617 



3-74 



165 



13-6 



186 



195 



127 



238 



7 ... 



358 



5-12 



85 



12-8 



98 



103 



68 



127 



8 ... 



5-10 



7-30 



40 



13-8 



45 



51 



33 



62 



9 ... 



22 



8-90 



25 



13-6 



29 



34 



22 



42 



