94 



THE LEVER. 



again produced. The sum of these weights will be the 

 true weight of the given article. 



178. Compound Lever. Sometimes it is not con- 

 venient to use a lever sufficiently long to make a given 

 power support a given weight. A combination of levers 

 called a compound lever may then be used. Hay-scales 

 may be mentioned as a familiar illustration of the com- 

 pound lever. In this case we have the following : 



Statical Law. Tl%e contin- 

 ued product of the power and 

 tJie lengths of the alternate 

 arms, beginning with the 

 power-arm, equals the contin- 

 ued product of the weight 

 and the lengths of the alter- 

 nate arms beginning ivith the 

 weight-arm. 



FIG. 45. 



EXERCISES. 



Note to the Pupil. If any of these problems be obscure to you. 

 remember that it will pay to draw an accurate figure or diagram of 

 the machine representing the several powers and weights in position. 

 Bee Fig. 40. 



