ORDINARY MEETINGS. 



XXX111 



rubber no doubt differed in degree of vulcanisation from Mr. Macdonald's, 

 and as he used a different initial stress, it is not surprising that the elon- 

 gations giving a minimum value for Young's Modulus should be 0.25 in 

 the one case and 0.5 in the other 



Mallock's mean value of Young's Modulus, when expressed in 

 absolute C. G. S. units, was 8.56 x 10 6 for soft grey india-rubber, and 

 34.16 x 10 6 for hard grey rubber. As in the case of the rigidity, Mr. 

 Macdonald's values are intermediate, being nearer Mallock's values for 

 the soft than for the hard specimen. 



(2) The following table contains the determinations made for the 

 second purpose mentioned above. 



PROC. & TRANS. N. S. INST. Sci., VOL. X. 



PROC. C. 



