494 Farm Mechanics. 



vice as it is in a locomotive ; there must be weight enough 

 to make a secure footing. It can be demonstrated with 

 the apparatus in Fig. 235 that two pounds at the place of 

 the center weight in the figure increases the ability of the 

 model to draw an equal amount when the traces' are hori- 

 zontal and, with the same added weight and the traces 

 given a slant of 20 degrees, the ability to draw is increased 

 4 pounds. 



These results mean that of two horses, each having a 

 muscular power capable of utilizing its full weight, the 

 heavier one will exert the stronger pull. The 1,200- 

 pound horse may pull about 200 pounds more than the 

 1,000-pound horse of like build when the traces are hori- 

 zontal and 400 pounds more when the traces slope at an 

 angle of 20 degrees. 



616. Influence of the Distribution of Weight on the Draft 

 of a Horse. It will be cleat from an inspection of the 

 model represented in Fig. 235 that to transfer the weight 

 from the center ring to the forward one, giving what is in 

 effect a horse with heavier shoulders, will make the weight 

 count for more in preventing the horse being raised off his 

 feet ; so, too, will it be evident that if the weight is shifted 

 to the hind quarters it must have much less influence on 

 the draft. 



Indeed, most horses in heavy draft, when given the free- 

 dom of the head, show that they understand this principle 

 in practice, by both lowering the neck and extending the 

 nose forward, thus giving this portion of their weight a 

 longer leverage to hold the body down on the hind feet 

 which are acting as a fulcrum'. 



617. Influence of the Strength of the Hock Muscle on the 

 Draft of a Horse. When a horse is drawing a heavy load a 

 tremendous strain is brought upon the muscles which 

 straighten the hock joint so as to force the body forward, 

 and the load after it, in walking; and it is a deficiency 

 of ability at this point oftcner than at any other which 

 limits the power of the horse as a draft animal. 



