XXVIll PROCEEDINGS. 
Sixra OrbDINARY MEsTING. 
Legislative Council Chamber, Halifax, 8th May, 1899. 
The PresrpEntT in the chair. 
A circular from the Royal Society of Canada, relative to the appoint- 
ment of a delegate to the forthcoming meeting, was read and referred to 
the Council for action. 
Pror. J. G. MacGrecor communicated a ‘ Note on the variation — 
with tension, of the elastic properties of vulcanised india-rubber,” being 
an account of some experiments made in his Laboratory at Dalhousie 
College, by Mr. W. A. Macponatp. 
The experiments had been intended originally to deal with rigidity 
only, but it had been found possible to apply some of the observations 
to the determination of Young’s Modulus as well. 
The composition of the specimen of india-rubber used was not 
known. It was in the form of a cylindrical cord and was fairly soft in 
texture and grey in color, a freshly cut surface having a mottled 
appearance. It had been obtained from Messrs. Thornton & Co., Edin- 
burgh, and was both very true and very uniform in its circular cross 
section. 
The method employed for determining the rigidity under tension 
was the method of oscillation. It was necessary therefore to fix the 
upper end firmly and to attach a weight-holder firmly to the lower end. 
As the problem had been assigned to Mr. Macdonald as a class exercise 
merely, and no appropriate gear for the attachment of the ends was 
immediately available, he had to be contented with a makeshift method. 
He drew the ends of the cord through pieces of glass tubing, previously 
coated internally with soft sealing wax, of considerably smaller diameter 
than the cord, and then gently heated the tubes until the wax melted. 
The tube at the upper end was fixed to a bracket, that at the lower end 
earried a cork disc which served as a weight-holder. To reduce the 
error due to lack of uniformity in the diameter of the cord near the 
ends, produced by the pressure of the tubes, the cord selected for use 
was a long one. Except in so far as the heating may have changed the 
physical properties of the cord near the lower end, the arrangement was 
satisfactory enough for the comparatively small extensions for which it 
was intended. But for the greater extensions, to which the earlier 
results made it appear desirable to proceed, it was not suitable. For 
