MECHANIC TOWERS. *2J 



on which the power acts, be seven times as far 

 from A as the point Z, on which the weight acts, 

 then one pound applied at C will raise seven pounds 

 at B. 



This lever shews the reason why two men carry- 

 ing a burden upon a stick between them, bear shares 

 of the burden which are to one another in the in- 

 verse proportion of their distances from it. For it 

 is well known, that the nearer either of them is to 

 the burden, the greater share he bears of it ; and 

 if he go directly under it, he bears the whole. So 

 if one man be at A, and the other at a, having the 

 pole or stick resting on their shoulders ; and if the 

 burden or weight B be placed five times as near 

 the man at A, as it is to the man at «, 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 being so yoked, as that 

 each horse may draw a part proportionable to his 

 strength ; which is done by so dividing the beam 

 they pull, that the point of traction may be as 

 much nearer to the stronger horse than to the 

 weaker, as the strength of the former exceeds that 

 of the latter. 



To this kind of lever may be reduced oars, rud- 

 ders of ships, doors turning upon hinges, cutting- 

 knives which are fixed at the point, &c. 



If in this lever we suppose the power and weight 

 to change places, so that the power may be be- 

 tween the weight and the prop, it will become a 

 lever of the third kind ; in which, that there may 

 be a balance between the power and the weight, 

 the intensity of the power must exceed the inten- 

 sity of the weight just as much as the distance of 

 the weight from the prop exceeds the distance of 



