ON DRAUGHT. 413 



one leg', is overcome by the united exertion of two. We shall point out, 

 hereafter, the necessity of attending- to this in the application of this power 

 to draug-ht. 



In trotting, the action is of course quicker, and a less resistance will, 

 as might be expected, cause the horse to move his legs at two intervals 

 instead of at four equal intervals of time : indeed, a horse accustomed 

 to go in harness generally acquires the habit of that action. There is 

 this striking difference between trotting and walking: in walking, we have 

 seen that the interval between the movement of the legs on the same side 

 was less than the other interval of time : in trotting, on the contrary, the 

 legs situated diagonally, or at opposite corners, move almost simultaneously. 

 Owing to the velocity and the momentum which the body acquires in 

 consequence of that velocity, in trotting fast, the successive impulses are 

 less distinctly perceptible, and the movement more continued and uniform 

 than in a slow trot, or in walking. 



In galloping, the movement is totally different : the fore legs are thrown 

 forward nearly simultaneously, and the hind legs brought up quickly, 

 and nearly together ; it is, in fact, a succession of leaps, by far the 

 greatest interval of time elapsing while the legs are extended after the 

 leap is taken : this is the position, therefore, which catches the eye, and 

 which must be represented in a drawing to produce the effect of a horse 

 in a gallop, although it is the moment when the animal is making no 

 exertion. 



The canter is to the gallop very much what the walk is to the trot, 

 though probably a more artificial pace. The exertion is much less, the 

 spring less distant, and the feet come to the ground in more regular suc- 

 cession: it is a pace of ease, quite inconsistent with any exertion of 

 draught. 



The consequence of these pecuhar movements in the limbs of the 

 animal is, that a succession of impulses is conveyed to the body ; and 

 when the movement is slow, and the body of the horse does not acquire 

 any considerable impetus or momentum, the resistance should be such as 

 to receive each of these impulses, and leave the horse unrestrained in the 

 intervals. 



It must, therefore, be a rigid resistance, void of elasticity. 



It must not, however, be a constant, unremitted resistance. 



For it is a well-known fact, that, however powerful may be the muscles 

 of a hmb, they must not be kept constantly on the stretch. Thus we feel 

 even more fatigue by standing than by walking, because one particular set 

 of muscles is then kept constantly exerted. It is evident, therefore, that 

 the resistance or draught must not be perfectly constant but should afford 

 frequent opportunities of relaxing the efforts. Neither must it be a yield- 

 ing resistance, as in that case the animal could not make any great 

 exertion ; for if he applied too much power, he would be liable to fall 

 forward, and should he at any time fall short of the necessary exertion, he 

 would be drawn back by the strain, and it would require a considerable 

 effort to restore the motion. 



If a horse be made to drag a rope passing over a pulley and descending 

 into a well with a certain weight, say of 200 lbs. attached to it, it is obvious 

 that he could not make an effort greater than 200 lbs. without instantly 

 considerably increasing his velocity, which would be a waste of power ; 

 nor must he for an instant relax his efforts, or fall below that mark, for he 

 would then be unable even to resist the pull, and would be overcome by 

 the weight. Such an extreme case as this, of course, is not likely to occur 

 often in practice, but the disadvantage of the principle is obvious. 



