TO MEASURE ENDLESS CHAIN POWEE. ISO 



carrier; and iig. 213 shows a two-horse power, (Emory's,) 

 with the wheel-work on which the endless^ platform runs. 

 The power of these machines, and the amount of fric- 

 tion in running them, may be easily ascertained by the 

 rule, already given in a former part of this work, for de- 

 termining the power of the inclined plane ; for the only 



Fis. 213. 



Two-horse Tread Power. 



difference between the endless chain and a common in- 

 clined plane is, that in one the plane is fixed, and the body 

 moves up its surface, and in the other the plane itself 

 moves downward, and the weight or animal upon it re- 

 mains stationary. The same principle apj^lies in both cases. 



First, to ascertain the friction, let the platform be placed 

 on a level, with the horse upon it ; then gradually raise 

 the end until the weight of the horse will just give it mo- 

 tion. This will show the precise amount of tlie friction ; 

 for if the end be elevated one-twentieth of its length, 

 then the friction is one-twentieth the weight of the horse 

 and platform. 



Secondly, to determine the power, when the end is still 

 further raised, measure the difference between the height 

 thus given and the length of the platform. If, for in- 

 stance, the height of the inclination is one-eighth of its 

 length, and the horse is found to Aveigh eight hundred 

 pounds, then the power is one hundred pounds, or one- 

 eighth the weight of the horse. 



