THE PRTNXIPLES OF MVODVNAMICS. 49 



32. In Figs. 1 5, 16 and 17, let f o c be the 

 fixed bone, a c b the movable bone, and c their 

 joint : in Figs. i5 and 16, the joint is in the con- 

 tinuity of the lever. Let P be the power, F the 

 fulcrum, and W the weight, whose tendency is 

 in the direction a w. On the line a w, as a 

 diagonal, construct the rectangle a e w d, one of 

 whose sides lies in the long axis of the movable 

 bone — prolonged if necessary. The dynamic tri- 

 angle is a e w. The dynamic aiigle is inchided 

 between the long axis of the movable bone — -pro- 

 longed if necessary, and the line of the tendency 

 of the lueight, and is e a w. 



33. The dynamic angle is generally ac2ite. It 

 may be a right-aitgle at one point only — but is 

 never greater than a right-angle. 



34. In Figs. 1 5, 16 and 1 7, illustrating respec- 

 tively levers of the first, second and third orders, 

 the line a d represents the resisting compon- 

 ent of the weight, and the line a e represents the 

 displacing component of the weight. 



35. In regard to the magnitudes of the rec- 

 tangular comp07ients of the weight, the following 

 conclusions may be drawn : 



