74 Proceedings of the Royal Society of Edinburgh. [Sess. 
the other. It is in fact the effect pointed out by Schuster. There is no 
action between the molecules. 
We have thus met with no evidence in favour of the existence of an 
effect of the nature mentioned by Kayser. 
The research was carried out in the Physical Laboratory of the Uni- 
versity of Glasgow with the aid of a grant from the Carnegie Trust for the 
Universities of Scotland. 
( Issued separately December 22 , 1908 .) 
