220 DRAUGHT AND HARNESS. 



and turning to Fig. 4, p. 40, which was constructed 

 altogether without reference to the question before 

 us, we find that the line E S is that in which the 

 propulsion is affected by the hind leg ; and now turn- 

 ing again to Fig. 1, and imagining a straight line 

 drawn from the middle point of the anterior edge of 

 the shoulder-blade, where the collar rests, and at right- 

 angles to it, we see that this line would, if prolonged, 

 go away to the rear just at the horse's hocks to the 

 point E, where it forms only a very small angle with 

 the line R S (Fig. 4) ; and it is quite evident that when 

 the horse, in leaning forward to draw, lowers his 

 forehand, the two lines will coincide very nearly ; or in 

 other words, the direction in which the propelling 

 force of the hind legs is effected will be exactly contrary 

 to that in which the resistance to the traction occurs 

 whereas with the horizontal trace it will form a 

 considerable angle with it at the point of attachment 

 to the collar. 



We have therefore the weight of evidence, both 

 practical and theoretical, in favour of the trace being 

 attached to the middle of the collar, and at right-angles 

 with it : and if this were not so, a horse with a bad, 

 that is to say a short straight shoulder, ought to be 

 better for draught than one with a long slanting one ; 

 for the horizontal trace is much more easily attained 

 with the former than with the latter. 



In forming a final opinion on this matter of the 

 angle of traction, the fact should never be lost sight of 

 that a high wheel, which always reduces this angle, 

 may, on account of the great mechanical advantages 

 inherent in itself, make a perfectly horizontal trace, or 

 even one inclined the wrong way to the horizon, 



