ANIMAL MECHANICS. 



461 



No. 2. — Mr. Jevons 1 Experiments — (Useful Effect) — (Holding 

 Arms horizontal). 



to 



Useful Effect 

 (observed) . 



Useful Effect 

 (calculated). 



Difference. 



I 



321 



320.7 



4 0.3 



2 



4>8 



480.7 



- 42.7 



4 



59 2 



597-5 



- 5-5 



7 



6l2 



602. 5 



+ 9.5 



IO 



603 



558.9 



4 44. 1 



14 



455 



493 7 



-38.7 



The maximum useful effect corresponds to a weight 

 5.45 lbs., equal to half the weight of the arm, and its value 

 is (132) 



A 



Maximum useful effect = — = 612. 



2U 



