162 POWER AND THE PLOW 



point on the base to cause about 9 per cent, increase in draft 

 and the angling of the point on the landside about 16 

 per cent, increase. Mr. Sanborn made trials of the same plow 

 before and after changing the shape, also of a new plow from 

 which the angles had been removed. 



The lessening of draft by slanting the share and shin of 

 the plow has caused the opinion that inclining the landside 

 also reduces the draft by giving a drawing cut. The fallacy 

 of this is apparent when it is remembered that angles in but 

 two planes are possible to the line of direction. The plow meets 

 the earth squarely and the beveling of the landside does not 

 tend to reduce the draft. It does, however, tend to equalize 

 the motion of the plow, as shown in Mears's invention, and it 

 has the further effect of giving a diamond-shaped furrow which 

 will topple over of its own weight when the width and breadth 

 of a furrow are nearly equal. Ox plows of the present day are 

 also made with beveled landside, because the slow motion of 

 the oxen does not give enough velocity to the furrow to throw 

 it over without an extreme twist to the moldboard. Land- 

 sides are of different heights, the highest being used for stubble 

 plows, on account of the depth of furrow. 



The frog is the foundation to which the landside, share, 

 and moldboard are fastened. It may be made of cast iron or 

 wrought steel. Connection may be by removable bolts and 

 rivets, or a solid weld. The brace separates the landside and 

 share and holds them rigidly. The beam connects the plow 

 bottom with the hitch. Wooden beams are rapidly giving 

 way to steel, owing to the scarcity of suitable timber. The 

 wooden beam is lighter, and while more easily broken than 

 steel is more elastic and will spring back into place after a 

 severe strain, so that the adjustment of the plow will not be 

 disturbed. They are more cumbersome, however, and at a 

 disadvantage in trashy ground. The more expensive steel 

 beams are composed of 60 to 80 point carbon steel as com- 

 pared to 30 or 40 point for the cheaper beams. The lower 



