THE PRINCIPLES OF MYODYNAMICS. 33 



parallelogram o s i c, which shall correspond 

 to and be twice as great as the myodynamic 

 triangle : — 



(i.) In Fig. 5, the components i c and c d co- 

 operate in the direction i c d, making the entire 

 displacing component equal i d : The whole 

 force of the contracting muscle appears in the 

 rectangular components. 



(2.) In Fig. 6, the component d c and the com- 

 ponent c d are antagonistic and equal, and there- 

 fore neutralize each other, so that there is no 

 displacing component : The whole force of the 

 contracting muscle appears in the moving com- 

 ponent. 



(3.) In Fig. 7, the component c d is greater 

 than the component i c by the component i d, 

 which is the displacing component : The whole 

 force of the contracting muscle appears in the 

 rectangular components. 



23. In a bony lever of the second order, let a 

 c i be a movable bone, o c, a fixed bone, c, their 

 joint, m, the contracting muscle, whose origin 

 and insertion are at o and i. See Figs. 8, 9, 

 10. The power is at i, the weight at c, and the 



