PROPULSION IN DRA UGHT. 



that the surface of the ground was not abnormally smooth and hard, like wood 

 or asphalte. From the foregoing considerations we may draw, with respect to 

 cart-horses that are required to exert their strength to the utmost, the following 

 deductions, which are fairly self-evident to practical men. 



1. Bodily weight, especially in the forehand, is an advantage in draught ; 

 for the greater it is, the more effective will be the push against the collar 

 caused by the centre of gravity falling beyond the base of support. Agreeably 

 to this fact, the experienced driver of a heavily-laden two-wheeled cart will 

 endeavour to place a fair share of the burden on the animal's back, so that 

 the horse may pull to the best advantage. The experiment of a man 

 succeeding in pulling along a stronger man than himself, by trying to do so, 

 while carrying a heavy weight on his back, is another familiar instance of this 

 principle. The gain in power from increased weight on the forehand is, also, 

 well illustrated by the practice, which is not very uncommon among drivers 

 of one-horse carts, of the driver mounting his animal and getting well forward 

 on its back, when he finds that it is unable to pull its load up a hill. 



2. The cart-horse ought to have a heavy neck as well as massive shoulders. 

 As a natural corollary to this proposition, which infers the lowering of the 

 head and neck, we must condemn the use of bearing reins with the class of 

 horse which we are now considering. 



3. The shoes of the horse should have toe-pieces when the ground is 

 favourable to their employment. 



On the other hand, when the horse, on account of the slippery nature of 

 the ground, is unable to use his fore legs, except to a very slight degree, as 

 propellers, the forehand should be light and the head carried high. Thus, 

 the weight has to be kept almost entirely off the shafts of London hansom 

 cab-horses, which would be rendered very liable to fall down on the greasy 

 wood pavement and glass-like asphalte, if a fair proportion of the load were 

 to be put on their backs. Not alone is weight kept off their backs, but as a 

 rule it is so distributed as to cause the backhand to exert on the " girth- 

 place " an upward pressure, which, naturally, will more or less aid in " lighten- 

 ing" the forehand. 



The force of propulsion given by the Jiind limb is dependent on a series of 

 levers which extends from the toe of the hind foot, along the bones of the 

 hind leg, pelvis, spinal column, up to the centre of pressure on the inner side 

 of the collar. It is manifest that the flatter this irregular line of levers is, 

 with reference to the line of propulsion from the toe of the hind foot to the 

 collar, the greater will be the mechanical advantage at which the hind limb 

 will act. Consequently, we may infer that the cart-horse should be long 



