264 Proceedings of the Royal Society of Edinburgh. [Sess. 
this table. The capacity was calculated from the mean of all these read- 
ings. It was found to be 176*45. 
The figures in Tables I. and II. demonstrate the accuracy of which the 
method is capable. 
We desire, in conclusion, to acknowledge gratefully that the greater 
part of the cost of the apparatus used for this investigation was met by a 
Research Grant from the Carnegie Trust. 
Heriot-Watt College, 
Edinburgh. 
{Issued separately February 18 , 1910 .) 
