148 POWER AND THE PLOW 



velocities, a fundamental principle involved in pulverization 

 noted by Jethro Tull in his description of the old f our-coultered 

 Berkshire plow. 



J. Dutcher, of Durham, N. Y., claimed discovery of a valu- 

 able principle in relation to the line of draft. He provided his 

 landside with "suction" i.e., an upward curvature of one 

 half inch maximum from a straight line drawn from point to 

 heel. This allowed the beam of the plow to be set level with 

 the base line. The plow would penetrate hard ground as well 

 as before, when the fore end of the beam was set high, and, the 

 entire sole being more nearly in contact with the bottom of the 

 furrow, the plow ran more steadily than when" running on its 

 nose." He pointed out that the draft line must be straight 

 from the horse's breast to the centre of resistance on the plow, 

 and that the point of hitch on the beam must lie within that 

 line. He condemned the long beams then in use as tending 

 to thrust the hitch forward of the proper line and necessitating 

 an upward inclination of the beam to counteract this ten- 

 dency. Two feet for hard ground and two feet four inches for 

 mellow he regarded as the extreme distances to which the 

 beam should extend forward of a perpendicular from the point 

 of the share 



John Mears, of the firm of Prouty & Mears, observed about 

 1833 that the irregularity in the running of the plows of that 

 time was caused to a large degree by the fact that the beam 

 was usually set so that the front end lay an inch or two to the 

 right of the plane of the landside produced to that point. 

 This was done to counteract the tendency of soil pressing on 

 the rear of the moldboard to force the plow point away from 

 the land. Mears saw that the centre of resistance lay only a 

 short distance to the right of the plane of the landside, the 

 force required for cutting the vertical wall of the furrow nearly 

 balancing the work of the share and moldboard. He inclined 

 the landside seven degrees toward the land, leaving the beam 

 directly over the point of the share, but parallel throughout 



