340 



Mr. E. Wilson. Aluminium as an Electrode 



phase difference but the effect we are looking for, namely, a large 

 ratio between the maximum coulombs in the two halves of a period, 

 mainly develops with large currents for a given frequency accom- 

 panied by high temperature and small phase difference. The average 

 watts have been deduced from the product of instantaneous volts 

 and amperes at twenty equal intervals during a period. 



The experiments in figs. 1, 2, 3 give results obtained with an 

 exploring electrode inserted between the plates in the electrolyte as 

 in the first portion of this paper. The aluminium and carbon plates 

 in one of the large cells were separated to J inch, and the two cells 

 kept in series as in experiments (4) and (5) Table IV. The curves 

 refer to this cell, and provision was made for obtaining the instan- 

 taneous values of the current in the cell, and the potentials between 

 the exploring electrode and either the aluminium or the carbon 

 plate. 



In figs. 1, 2, the Siemens dynamometer in the circuit registered 

 the same current, namely 3*97 amperes, but the frequencies are 16 

 and 98'5 respectively. We see that T T second is too short to allow 

 the effect we are looking for to fully develop, since the ratio of the 

 maximum coulombs is 1'47. On the other hand, if we examine the 

 two sets of curves we see that at 98 periods per second the potential 

 difference between the exploring electrode and aluminium has a 

 maximum value of 3'63 volts during the half period when the 

 coulombs have the smaller maximum, whereas at 16 periods per 

 second, the same maximum current is produced with a larger 



