128 ENERGY IN TORSIONAL OSCILLATION 



attached to the end H of the lever was 3000 gins., and the 

 ratio of the arms 3 to 1, the fulcrum I being half way between 

 the cam P and the end C, while PH=PC. The pull exerted 

 is therefore in this case 9000 gms. weight. The values 

 got on testing this wire after heating to 485 C., and before 

 fatigue was applied, were 



a=2, n=2-15 and 2-70 ; 



a then is seen to be raised to a value intermediate to those 

 obtained from the fresh and heated wires. Similarly n has 

 now an intermediate value. 



The effects of both forms of fatigue on the empirical 

 equation as applied to other materials will be the object of 

 further research. 



JAMES BONNYMAN RITCHIE 



