330 AGRICULTURAL ENGINEERING 



farms of the West, the whole team is controlled largely by the 

 two leaders. Thus, if a 24-horse team is to be made up, the 

 two leaders will be followed by four horses abreast and these 

 by the others arranged six abreast. 



The Principles of Draft. Although horses have been 

 used as draft animals since the dawn of history, it is strange 

 to note that the principles of draft are not clearly understood, 

 many points being open to argument. The individual 

 horse owner has not felt justified in making exhaustive experi- 

 ments for his own benefit, and no professional experimentalist 

 has found it possible to give the matter attention. Mr. T. 

 H. Brigg, of England, who studied the subject of horse haul- 

 age, states that on an average the horse is made to waste as 

 much as 50 per cent of his energies. In farm practice this 

 would evidently not be true; yet, if it is only partly true, the 

 horse offers a fertile field for profitable investigation. 



The amount of resistance that a horse can overcome, or 

 the draft that he can exert, depends upon several factors; viz., 

 his weight, height, and length, his grip upon the road surface, 

 his muscular development, and the direction of the traces. 



Weight. A heavy horse has several important advan- 

 tages over a light one. In the first place his adhesion to 

 the road surface is better, there is less tendency for him to 

 slip; and, in the second place, with the heavy horse there is 

 less tendency in pulling to lift the forefeet from the ground. 



Height and Length. The latter point also indicates the 

 advantage that a long-bodied horse has in pulling. The 

 height of the horse may or may not be to his advantage, 

 depending upon the height of hitch. It is common occur- 

 rence to see the efforts of a horse limited by his weight and 

 length, as his forefeet are lifted from the ground without 

 permitting him to exert his full strength. It is an easy matter 

 to demonstrate that a horse can increase his maximum 



