128 THE OLIVER PLOW BOOK 



Shallow plowing of sods puts more work on the share 

 and less on the mouldboard. Deep plowing of sod 

 lessens the work of the share and puts more work on the 

 mouldboard. The same is true of stubble. 



The curvature of the upper part of the share, the 

 mouldboard, and the angle of the mouldboard to the 

 furrow slice have to do with the pulverizing qualities of 

 the bottom as well as the draft. 



The increase in the speed of a plow in dry, hard 

 plowing aids materially in better pulverization, but 

 while it is doing better work it increases the power re- 

 quired. A plow bottom shaped to do the proper work 

 at a speed of two and one-half miles an hour will 

 throw the dirt from two to three times as far when 

 travelling at twice that rate of speed. 



