1911.] 



Decomposition of Organic Compounds. 



273 



platinum electrodes and a pair of non-polarisable electrodes. "With this 

 arrangement four possible combinations of the electrodes are possible : — 

 I. A pair of platinum electrodes. 

 II. A pair of non-polarisable electrodes. 



III. A platinum electrode in the jar and a non-polarisable one in the 



porous pot. 



IV. A non-polarisable electrode in the jar and a platinum one in the 



porous pot. 



With a zinc-sulphuric acid cell, in which the constancy of the relative 

 charges upon the four pairs of electrodes had been determined, the following 

 facts were observed when the zinc was added to the sulphuric acid in the 

 jar :— 



I. Platinum-platinum electrodes. After a short interval an E.M.F. was 

 developed which soon attained its maximum, and then gradually died away 

 as the zinc was consumed (fig. 6). 



II. Non-polarisable electrodes in both jar and porous pot. No E.M.F. was 

 developed ; that is, the discharge of the condenser through the galvanometer 









































Fig. 6 



















































































a 



The black line indicates E.M.F. developed in a zinc-sulphuric cell from 

 oair of platinum electrodes ; the dotted line that from a platinum 

 ctrode in jar and a non-polarisable electrode in porous pot. Initial 

 nperature 11° C. 



! 1 1 1 I 1 1 







ele 

 tei 









10 20 30 40 50 60 70 80 90 100' 



