58 FERGUSON'S LECTURES. 



^ * 6Ver ^ ^ e second kind Ilas tne weight between 

 the prop and the power. In this, as well as the former, 

 The S e- the advantage gained is as the distance of the power 



fr m the pr P to the distance of the weight from the 

 prop : for the respective velocities of the power and 

 weight are in that proportion ; and they will balance 

 each other when the intensity of the power multiplied 

 by its distance from the prop is equal to the intensity 

 of the weight multiplied by its distance from the prop. 

 Thus, if AB be 

 a lever on which 



_x-*. 



the weight W of 

 6 ounces hangs 

 at the distance 

 of one inch 

 from the prop 



/ \ ri 



G, and a power ( )w p y' 



P equal to the 



weight of one 



ounce hangs at the end B, 6 inches from the prop, by 



the cord CD going over the fixed pulley E, the power 



will just support the weight ; and a small addition to 



the power will raise the weight 1 inch for every 6 inches 



that the power descends. 



This lever shews the reason why two men carrying a 

 burden upon a stick between them, bear unequal shares 

 of the burden in the inverse proportion of their dis- 

 tances from it. For it is well known, that the nearer 

 any of them is to the burden, the greater share he bears 

 of it : and if he goes directly under it, he bears the 

 whole. So, if one man be at G, and the other at P, 

 having the pole or stick AB resting on their shoulders ; 

 if the burden or weight W be placed five time,? as near 

 the man at G, as it is to the man at P, the former will 

 bear five times as much weight as the latter. This is 

 likewise applicable to the case of two horses of unequal 

 strength, to be so yoked, as that each horse may dra\v 

 a part proportionable to his strength ; which is done 

 by so dividing the byeam they pull, that the point of 



