ANIMAL MOTORS 2Q3 



Intermediate load and speed the horse is able to do the 

 maximum amount of work. 



413. Best conditions for work. The average horse will 

 walk from 2 to 2^4 miles an hour, and at the same time 

 overcome resistance equal to about one-tenth or more 

 of his weight. Work may be performed at this rate for 

 ten hours a day. Assuming the above to be true, a 1,500- 

 pound horse will perform work at the rate of one horse 

 power. 



As 1,500 pounds is much above the average weight of 

 a farm horse the average horse whose weight is not far 

 from 1,100 will do continuous work at the rate of about 

 2/3 to 4/5 horse power. 



414. Maximum power of the horse. Entirely different 

 from other motors, the horse, for a short time at least, is 

 able to perform work at a very much increased rate. A 

 horse when. called upon may overcome resistance equal 

 to one-half his weight, or even more. The horse power 

 developed will be as follows, assuming that he walk at 

 the rate of 2^ miles an hour (see Art. 20) : 



^ 1,500X54 X 2^X5,280 



Jrl. F. 5 



33,000 



A horse will be able to do work at this rate for short 

 intervals only. The fact that a horse can carry such a 

 heavy overload makes him a very convenient motor for 

 farm purposes. 



The maximum effort or power of traction of a horse is 

 much greater than one-half his weight. A horse weigh- 

 ing 1,550 pounds has been known to overcome, when pull- 

 ing with a horizontal trace, a resistance of 1,350 pounds. 

 With the point of hitch lowered until the trace made an 

 angle of 27 with the horizontal, the same horse was able 

 to give a draft of 1,750 pounds. It is believed, however, 

 that this horse is an exception. 



