20 
Proceedings of the Royal Society of Edinburgh. [Sess. 
son’s large value for change of density for a small stretch up to breaking- 
point, compared with our results, would suggest that the change of density 
for the most part occurred at or near the rupture. 
H. Tomlinson * has studied the effect of stretching to near breaking-point 
on the density of silver, copper, iron, and other wires, but not of lead. He 
found that the percentage change of specific gravity, for a permanent 
increment of length of 1 per cent., ranged from —*0082 for aluminium 
to —‘0620 for platinum, being — 0156 for silver, f 
* Phil. Trans., 174, 1, 1883. 
t The above experiments were carried out by the aid of a grant from the Moray 
Endowment for the Promotion of Research. 
( Issued separately April 4, 1907.) 
