136 THE PRINCIPLES OF MYODYNAMICS. 



neck : — The rectangular components of the 

 contracting muscle will be a d and d o ; and a d 

 will be a retentive component and d o will be a 

 moving component. In a given case, as ap- 

 proximately measured, the retentive component 

 ad was 9, and the moving component do was 

 3 : Hence, the force of gluteus medius was 

 9.5 nearly. 



133. Now let the weight of the lower limb 

 pull directly downward in the direction i P W : 

 draw i e perpendicular to P F : Then will i e 

 and e p be the rectangular components of the 

 force of the weight of the lower limb. But i e 

 is a resisting component and e p is a displacing 

 component ; and e p will tend to counteract the 

 retentive component a d ; and i e will counteract 

 the moving component d o : The force of i e 

 will equal the force of d o ; but the force of e p 

 will be less than the force of a d. Draw o H 

 parallel to i p : Then will d H represent the 

 force of e p : — This will reduce i e and o d, and 

 p e and H d to the same denomination : — And 

 then will a H represent the retentive compon- 

 ent of the power and the weight acting on the 



