[CLARK] ■ CAPILLARY ELECTROMETER 85 



Measurements of capacity in tubes large enough to permit the 

 measurement of wetted area yield a calculated thickness of the double 

 layer substantially the same as that given by Lippmann. 



If we admit the existence of a double layer, the change in capacity 

 with the applied difference of potential seems to indicate a change in 

 the thickness in the double layer brought about by the charges on 

 the plates of the layer. 



In conclusion, I have to thank Mr. A. L. Greenlees for his pains- 

 taking care in carrying out nearly all of the experimental work in the 

 foregoing paper. 



Physics Laboratory, Queen's University 

 Kingston, Canada. 



