Line of Draught of Plows. 169 



In speaking of the proper angle of draught, Mr. Stephens 

 remarks ("Book of the Farm," page 286): 



" The reasoning heretofore adopted on this branch of the 

 theory of the plow seems to be grounded on the two following 

 data: the height, on an average, of a horse's shoulder, or that 

 point in his collar Avhere the yoke is applied; and the length of 

 the draught chains that will give him ample freedom to walk. It 

 falls out, fortunately, too, that the angle of elevation thus pro- 

 duced crosses the plane of the collar as it lies on the shoulders 

 of the horse when in draught, nearly at right angles." 



It may, however, be shown that the plow may be drawn at any 

 angle from the horizontal nearly up to the perpendicular, if 

 certain practical diiSculties were removed, and that would require 

 a continually diminishing force to draw it as the line of draught 

 approaches to a horizontal direction, arriving at a minimum when 

 it reaches that point. It is, however, impossible in practice to 

 apply the force in this direction, as the line of draught would, in 

 this case, pass through the solid earth of the furrow slice; but it 

 is practicable to draw the plow at an angle of 12 degrees, which, 

 as will be demonstrated, will require less draught by fourteen 

 pounds than would be required if the angle were 20 degrees, 

 which may be considered as the average in the ordinary practice 

 of plowing. A plow drawn at this low angle, viz., 12 degrees, 

 would have its beam (if of the ordinary length) so low that the 

 draught-bolt would be only ten inches above the base line; and 

 this is not an impracticable height, though the traces might be 

 required inconveniently long. On the same principle, the angle 

 of draught might be elevated to 60 or 70 degrees, provided a 

 motive power could be applied at such high angles. In this, as 

 before, the beam and clevis would be in the straight line between 

 the point of attachment at the collar and the centre of resistance. 

 The whole plow, also, under this hypothesis, would require an 

 almost indefinite increase of weight; and the power required to 

 draw the plow, at an angle of 60 degrees, would l)e nearly twice 

 that required in the horizontal direction, or li| times that of the 

 present practice, exclusive of what might arise from increased 

 weight. We may, therefore, conclude that to draw the plow at 

 any angle higher than the present practice is impracticable, and, 

 though rendered practicable, would still be highly inexpedient 

 by reason of the disadvantage of incrersed force being thus ren- 

 dered necessary, unless we can suppose that the application oi 



