1876.] Rev. S. Haughton on the Laiv of Fatigue. 133 



W2 R2 = = constant, 



T being the total time of work. • 



The Law of Eatigue may be applied in one or other of two wa^^s. 



W + W 



V, The total work done is + W.^, and the rate of work — ^— ^• 



Hence the Law of Fatigue gives us 



(Zx+W^' = constant (t) 



The d}Tiamical work is proportional to cc, the length of the arm, to 

 IV -\- a, the weight plus half the weight of the arm, and to n the number 

 of lifts. 



The statical work is proportional to the length of the arm, to 

 w-j-a, the weight plus half the weight of the arm, and to T the total 

 time. 



The total time T is proportional to 



?i, the number of lifts, 

 and to t, the time of each lift. 



Hence ec^uation (1) becomes 



(^+.)W(i+, 3jy ^ 



nt 



where /3 is an unknown constant. But w-\-a and x are constants in 

 these experiments, and hence we find equation (1) reduced to the follow- 

 ing :— 



^iM = A (2)* 



