L90 Dr. C. 1\. A.Wright on the Determination of 



to saturate as far as possible, not only the liquids surrounding the 

 electrodes with the gases respectively evolved on the electrodes, 

 hut also the interior of the foils with occluded gases. The elec- 

 trodes were then rapidly removed, rinsed with recently boiled 

 just cool acid to remove adherent solution of hydrogen or 

 oxygen, and dipped into a U-tube containing the same recently 

 boiled just cool acid. On connecting the two pieces of foil with 

 a quadrant-electrometer a considerable potential difference was 

 at once indicated. The two pieces of foil were then connected 

 by a shortcircuiting wire for a short time (ten seconds usu- 

 ally) ; on removal of the wire, the foils being still connected 

 with the electrometer, the spot of light moved regularly for a 

 considerable time, indicating a gradual increase in theE.M,F. 

 of the voltaic arrangement thus produced, from at the mo- 

 ment of removal of the shortcircuiting wire up to a maximum, 

 which was maintained for some time, after which the E.M.F. 

 gradually fell, precisely as in the experiments just described. 

 It is evident that this development and rise of the E.M.F. set up 

 was due to the formation and increase of an aura of gas round 

 each electrode, the source of which was clearly the gas occluded 

 internally in each respectively, the which gas now passed out- 

 wards by a reversal of the process by which it formerly passed 

 inwards. The following three sets of readings (averages of 

 fairly concordant repetitions of each experiment) will serve as 

 specimens of a large number of analogous results ; the num- 

 bers show the E.M.F. set up after the annexed time had 

 elapsed : — 



Voltameter used 



" Largest." 



'•' Largest." 



"Medium.*' 





Value of E on breaking circuit 1 

 in the first instance (had been 1 

 maintained for several days [ 

 previously) j 



1-05 volt. 



1-95 volt. 



2-20 volts. 



Time, after removal of shortcir- 

 cuiting wire : — 



5 seconds.... 



volt. 

 •14 

 •19 

 •21 

 •23 

 •25 

 •27 

 •28 

 •29 

 •29 

 •28 

 •28 

 •27 

 •26 

 •245 

 •235 

 •23 



volt, 

 •35 

 •41 

 •43 

 •45 

 •47 

 •52 

 •55 

 •57 

 •59 

 •59 

 •57 

 •53 

 •49 

 •44 

 •42 

 •40 



volt, 

 •39 

 •44 

 •47 

 •50 

 •52 

 •55 

 •58 

 •59 

 •60 

 •58 

 •55 

 •50 

 •34 

 •31 

 •29 

 •28 



10 „ 



15 „ 



20 ;; ::.;: 



30 „ 



1 minute 



2 minutes 



3 „ 



7 ., 



10 „ 



15 „ 



30 „ 



1 hour 



2 hours 



3 „ 



4 ., 





