172 Report on Trials of Plows. 



the direction c 6, and attached firmly to the plow's body, any- 

 where between c and y, would answer all the purposes of draught, 

 perhaps better than the present beam. But the draught not 

 being the end in view, but merely the means by which that end 

 is accomplished, the former is made to subserve the latter; and 

 as the beam, if placed in the direction c 6, would obstruct the 

 proper working of the plow, we are constrained to resort to 

 another indirect action to arrive at the desired effect. This 

 indirect action is accomplished through the medium of a system 

 of rigid angular frame work, consisting of the beam and the 

 body of the plow, or those parts of them comprehended between 

 the points b h c, the beam being so connected to the body, a h, as 

 to form a rigid mass. The effect of the motive force applied to 

 this rigid system of parts at the point b, and in the direction bf, 

 produces the same result as if c 6 were firmly connected by a bar 

 in the position of the line c b, or as if that bar alone were 

 employed, as in the case before supposed, and to the exclusion 

 of the beam, b h. - 



Let us now proceed to examine the effect of the oblique draught 

 on traction. The average draught of plows at the Albany trials 

 in 1850, was 407 pounds, with a furrow seven inches by ten 

 inches, when exerted in the direction b f. If now we take the 

 value of the line b f at 407, a certain portion of the force will be 

 exerted in direct traction, and another portion will be exerted 

 in pulling the plow up from the ground in the direction i f, 

 and the force of traction will be to the lifting force in the 

 exact ratio of the line i b to the line if. The line if is 50 inches 

 — 16 inches = 34 inches : the line b f is 120 inches; the line i b 

 is therefore 115 inches; and we therefore have 120 inches : 115 

 inches : : 407 pounds : 390 pounds = the amount of direct draught 

 upon the plow exerted by the horses. In like manner the force 

 lifting the plow upwards is found to be 114 pounds. The same 

 result would follow if the beam were supported by a wheel under 

 the point b; the wheel would then bear up the beam with the 

 same force as that by which it was supposed to be suspended, 

 viz.: 114 pounds. But to carry out the supposition, let the 

 draught now found be applied at the point c; as the plow would 

 then have no tendency to dip or rise, the force, k b, vanishes, 

 leaving only the direct horizontal force, i b; hence, were it pos- 

 sible to apply the draught in a horizontal direction from the point 



