THE PRINCIPLES OF MYODYNAMICS. 43 



d i 



a=m X . . . . (2) ; 



i o 



do 



b=a X . . . . (3) ; 



d i 



do 



b=m X . . . . (4) ; 



i o 



i o 



m=a X . . . . (5) ; 



d i 



i o 



m=b X . . . . (6) ; 



d o 



28. It will be convenient to call the right 

 angled triangle o d i, Fig. 14, the component tri- 

 angle. Hence, by the above formulae, when two 

 sides of the component triangle and one of the 

 related forces are known, it is possible to find 

 either of the other two forces. It will not be 

 necessary to translate these formulae into written 

 rules. 



29. A. In so far as the force of the contract- 

 ing muscle is concerned, the johit between a 

 movable bone and a fixed bone will be in a con- 



