138 



Messrs. Gee and Holden on 



Table I.— Showing Effect of (1) Size of Anodes, 

 (2) Previous history of Electrodes. 



k= constant of galvanometer ='000365 ampere. 

 S =surface of anode=Z x *06 sq. cm. approximately. 

 I— length of anode. 



The electrodes used were of platinum, one of them being a 

 plate 40 millim. x 8*5 millim., the other a wire -2 millim. dia- 

 meter, vhose length was varied during the experiment. These 

 were placed in strong pure H 2 S0 4 , and a battery with an 

 E.M.F. of 6 volts employed. 



Eemarks. 



1. Had been passing current a long time 



in /3 direction 



2. Ditto 



3. Washed and heated electrodes 



4. Current on in a direction for 15 



seconds 



5. Ditto for 60 seconds 



6. Wiped electrodes with paper. Shows 



influence of unclean electrodes 



7. Washed and heated electrodes , 



8. Current on in a direction for 30 



seconds 



9. Ditto for 45 seconds 



10. Broke circuit ; lifted electrodes up 



and down in the liquid several times. 

 Film evidently not thoroughly re 

 moved by this process, and there- 

 fore easily reformed 



11. Broke circuit; lifted electrodes out 



of liquid for 10 seconds, then moved 

 them up and down in liquid for 

 30 seconds 



12. Mixed treatment 



13. Current on in a direction for a moment 



20 

 10 



ampere 

 £287 = '105 

 k 140 =-0511 

 £100 =-0365 



k 90= -0328 

 k 92= 0335 



k 240= -0876 

 k 110 ='0402 



£150= -0547 

 k 120= -0438 



k 70 =-0255 



k 130= -0475 

 k 63= -0230 

 k 67 =-0245 



A. 



ampere 

 per sq. cm. 



•87 

 •85 

 •61 



•55 

 •56 



1-46 

 •67 



•91 

 •73 



•43 



•79 



•77 

 •82 



The resistance of the voltameter was, as estimated by Ohm's 

 method, 45 ohms in the a direction of the current, and 4500 

 ohms in the ft direction when the film was formed. In- 

 creasing the E.M.F. of the battery made no difference in the 

 value of C. 



