28G RIGIDITY OF VULCANIZED INDIA-RUBBER. HEBB. 



There is some lack of regularity in the results of this table- 

 so far as the determinations with smaller loads are concerned, 

 but the divergence from regularity is probably within the limit 

 of error of the observations. The results obtained with the 

 larger loads exhibit much greater regularity than the results of 

 the previous series of observations. The table shows that if the 

 tension be increased as rapidly as is consistent with the deter- 

 mination of the rigidity at successive stages, the rigidity 

 increases with the tension continuously, at first comparatively 

 slowly, and finally with greater rapidity. 



The comparatively slow increment of the rigidity under the 

 smaller loads would suggest the possibility that the rigidity 

 may not appreciably vary with the tension at all under the 

 circumstances aimed at in the experiments. For in the light of 

 the results of Table IV the larger values of the rigidity under 

 the greater loads may be due entirely to the time effect of 

 the previous increments of load. 



