52 



MECHANICS. 



A more compact arrangement of compound levers is 

 shown in fig. 51, where the power, P, acts on the lever 



A, exerting a force on the 

 lever B five times as great as 

 the power. B acts on the 

 lever C with a force increased 

 three times, and this, again, 

 on the weight, W, with a 

 four-fold force. Multiplying 

 5, 3, and 4 together, the prod- 

 uct is 60 ; hence a force of 

 one 2)0und at P w^ill support 

 GO pounds at W. By gradu- 

 ating (or marking into 

 iijvj "^ notches) the lever C, so that 



Compound levers. the distance is measured as 



the weight is moved along it, a compact and powerful 

 steelyard for weighing is formed. 



WEIGHING MACHIXE. 



A valuable combination of levers is made in the con- 

 struction of tlie weighing machine., used for weighing cat- 

 tle, wagons loaded wdth hay, and other heavy articles. 



Weighing Machine. 



The wagon rests on the platform A (fig. 52,) and this 

 platform rests on two levers at W, W, which presses their 

 other ends both on a central point, and this again bears on 



