238 Experimental Inquiry on Draught in Ploughing. 



ing a boat than in towing it from the bank. The nearer the 

 horse is brought to the plough, the more he will draw upwards, 

 and the more of this advantage, whatever it be, he will obtain. 

 The two horses are in general brought as near to it as is consistent 

 with the freedom of their hind legs. There is, however, in the 

 Scotch harness, a contrivance by which the line of draught is 

 shortened still more, and to which Mr. Morton justly, I think, 

 attaches much importance. In this neighbourhood, the trace of 

 the horses is not supported on their back, but passes in a straight 

 line from the point of their shoulders to the beam of the plough : 

 so that they draw, of course, from the shoulder. I do not know 

 whether this is general ; but it is certainly figured so in many 

 works on agriculture where this question of draught is treated ; 

 and treated, I must say, most inconclusively. But, in the harness 

 of these Clydesdale horses, who worked here so admirably, there 

 was a back-band of strong leather, 3 J inches wide, moveable along 

 the back of the animal to different points, which carries the traces 

 level from the collar ; so that the line of draught is shortened con- 

 siderably, and the horses work at the same time from the back 

 with an uplifting power, and from the shoulders with an advanc- 

 ing power. The advantage thus given may, I think, be very 

 considerable ; indeed, no one will regard the direction of a horse's 

 exertions as a slight matter, who recollects that extreme case in 

 which, as Sir David Brewster informs us, a strong man disco- 

 vered that, by placing himself in a certain posture, he could with- 

 stand the efforts of two horses pulling against him. 



But there is even another circum^stance which may render a short 

 draught advantageous in ploughing, and I will merely mention it 

 in the hope of drawing the attention of mechanicians to a subject 

 on which I must say I have not found in books anything satis- 

 factory : I mean, that an uplifting draught may be best suited to 

 the force which it is the object of the plough to exert. For that 

 force is an uplifting one, as regards the earth to be raised, as well 

 as an advancing one, as regards the progress to be made by the 

 plough itself along the furrow. It appeared, too, in Trial II., 

 that the friction arising from the plough's own weight occasions a 

 large part of the force which the horse has to expend ; but the 

 more the horse draws upward, the less of course will the plough 

 press on the ground. I leave this point, however, to be consi- 

 dered by those who are able to discuss it on mathematical prin- 

 ciples, and return to the immediate question, how far two horses 

 abreast can, with the same plough, do the work, on strong land, 

 of three harnessed in line. 



The two Clydesdale horses were, I think, able, at Lyford, 

 with as little exertion, to draw King's wo9den swing-plough, 

 which showed a draught of 24 stone, as were three horses of 



