HIGH AND LOW ATTACHMENT 351 



When horses are used for draft purposes on pave- 

 ments, their weight becomes a factor of prime impor- 

 tance. Manifestly, it is not convenient in great cities 

 (especially American cities) to hitch several horses to 

 one wagon. Fortunately, most of our streets are wide 

 enough to permit of two being driven abreast, and, 

 when so driven, they are most efficient in backing a 

 load. On pavements, horses get but a precarious foothold 

 for pulling. On moderately soft ground, they are able, 

 by placing the feet well back, to bring the soles of the 

 feet at an angle of fifteen to twenty degrees from the 

 horizontal, or the direction of the movement of the load. 

 On the smooth pavements, no such advantage can be 

 taken, and here efficiency of draft depends largely on 

 the weight of the horse. If, then, friction on the 

 pavement becomes so important, can the line of draft 

 be so adjusted as to increase it? It is evident that if 

 the point of attachment to the load be low, the friction 

 of the feet of the horse on the pavement will be 

 increased; if the point of attachment be high, it will 

 be diminished. Therefore the doubletrees should be 

 placed in a supporting iron under the tongue of the 

 wagon, especially if the wagon has low front wheels 

 and is used for heavy traffic. The farther back the 

 doubletrees are placed, and the shorter the traces, 

 the more pronounced will be the angle of draft and 

 the greater the traction power. 



A horse weighing 1,500 pounds when tested, by 

 placing the attachment to the load but six inches from 

 the ground, was able to pull 2,310 pounds as measured 

 by dynamometer. When he was attached to the load at 



