500 



Farm Mechanics. 



normal attitude to its limbs and on this account the fatigue 

 is supposed to be and probably is less. 



FIG. 240. The tread, power. 



In order that a large per cent of the labor expended by 

 the horse, when working on the tread power, shall become 

 available it is very important to have all of the bearings 

 clean, free from dust and grit and well oiled. There are 

 so many of these bearings and they are of such a character 

 that great care is required in running this power to avoid 

 heavy loss of efficiency due to friction. 



624. Working the Horse in the Tread Power When a 



horse is put into a tread power to work he accomplishes 

 the result by lifting his own weight against the force of 

 gravity and the more steeply the power is inclined and 

 the faster the horses walk the more work they do. Inclin- 

 ing the power so that the bed rises 2 feet in 8 feet requires 

 the horse to lift i of his own weight, thus producing a 

 pull equal to that on the belt when it travels at the same 

 rate. This for a 1,600-pound horse represents a pull of 

 400 Ibs. ; for a 1,200-pound horse, 300 pounds ; and for an 

 800-pound horse, 200 pounds. If, under these conditions, 

 the horse walks at the rate of 2 miles per hour, the work 

 done will be 2.13 H. P. for the 1,600-pound horse, 1.6 



