PLOWS FOR ANIMAL POWER 161 



qualities of the former with the lightness and elasticity of the 

 latter. Some share points, as well as the shin of the moldboard 

 and the heel of the landside, are reinforced with extra material 

 on account of the heavy wear on those places. To avoid the 

 rapid narrowing of the furrow as the heel wears away some 

 shares are given a truncated (blunt) heel, the edge of which 

 is almost parallel to the landside. 



The moldboard receives the furrow from the share and turns 

 it. Its shape has been and will be discussed elsewhere. The 

 landside counteracts the side pressure caused by the cutting 

 and turning of the furrow. Most plows are given "suction" 

 i.e., the lower face of the landside is raised in the middle from 

 a straight line drawn from point to heel. This is to cause the 

 plow to enter the soil easily and run at the proper depth in spite 

 of the lift by the traces on the end of the beam. The suction 

 is usually about one eighth of an inch, being increased for hard 

 ground and often dispensed with entirely in light soils. 



The cast shoe, or heel plate, often used under a steel landside 

 saves wear and affords the necessary bearing surface. It is 

 adjustable as to width, as required for different soils, and for 

 depth, so that as the plow point wears off the heel can be raised 

 to keep the plow in the ground. In addition to the downward 

 suction the landside is usually made concave by turning the 

 point of the share outward from one eighth to three eighths 

 of an inch. This is for the purpose of making the plow "take 

 land" i. e., cut full width. The effect of these deviations from 

 a straight line between point and heel is to increase the draft, 

 as more power must be applied to overcome the tendency of 

 the plow to run toward the land and deeper. The plow runs 

 less steadily, the motion being a succession of jumps, the effect 

 of which may be seen on the bottom of the furrow, and the 

 presence of concavity on either face of the landside is really a 

 confession of wrong adjustment to the plow. Prof. J. W. 

 Sanborn, who, next to Gould, has probably made more draft 

 tests of plows than any other man, found the dipping of the 



