Manchester Meuioirs, Vol. Iv. (1911), No. VZ. 19 



same conclusion in 1866. A reference to his paper con- 

 firms the authors' results as to the extension and con- 

 traction on heating under tension, and they hope to extend 

 their observations on this subject. 



The Mechanical Hysteresis of Rubber. 



If a rubber test piece be subjected to a gradually 

 increasing load to some point below the breaking load of 



Ftp-. 10. 



A. 



Rubber Testintr Machine. 



the specimen, and on reaching this point the lead be 

 reduced at the same rate to zero, it will be found that 

 the length of the test piece has been increased by a 

 certain amount of sub-permanent set. 



