206 Proceedings of Royal Society of Edinburgh. [sess. 
From Table IY. it may be seen that C, the point of maximum 
elongation, in every case lags behind the point M, where maximum 
elongation should occur if the fibres were perfectly free to rotate. 
This fact furnishes us with a clue to the cause of the difference 
between the actual behaviour of the yarn and the result deduced 
by analysis. The yarn fibres have acquired a 1 set ’ in one 
direction during the single twisting, which retards the contrac- 
tion in the second twisting until a later period. 
In concluding this paper, the author has pleasure in acknowledg- 
ing his indebtedness to the Carnegie Trust for the Universities of 
Scotland for the financial assistance which has enabled him to 
prosecute the research. 
( hsued separately June 19 , 1906 .) 
