THE PRINCIPLES OF MYODYNAMICS. 63 



force in the continuity of the lever acts to the 

 carpal end of the lever was i inch. 



47. In the case in which the dimensions of 

 the hand-lever were measured, let the entire 

 weight of the body — i5o pounds — rest on a re- 

 sisting surface through the heads of the meta- 

 carpal bones. The hand is now a lever of the 

 second order : The weight of the body equals 

 the pressure of the carpus on the base of the 

 radius.— ^ ^ have two equations, and two un- 

 known quantities : 



i5o+P=W . . . . (i.) 



4xP=3xW .... (2.) 

 From these equations we find the values of 

 P and W : 



Pi=45o pounds .... (3.) 



W=6oo pounds .... (4.) 



In this case : (i.) When the hand is extended 

 the fulcrum is on the palmar aspect of the heads 

 of the metacarpal bones ; (2.) When the hand 

 is flexed the fulcrum is on the dorsal aspect of 

 the heads of the metacarpal bones. 



48. In the next place, let the hand-lever, as a 

 lever of the third order, having the same dimen- 



