TILLAGE MACHINERY 69 



The steam plow may, in some cases, in certain soils, 

 be the means of producing an increase of yield of crops, 

 by plowing to a greater depth than could be done by 

 horse power. 



102. The set of walking plows. The original set of a 

 plow, or the proper adjustment of its point, share, and 

 bearn^is given by the maker. rLach time when the plow 

 is sharpened the smith is depended upon to return this 

 set to the plow. 



103. Suction. The suction of a plow is usually meas- 

 ured as the width of the opening betweef] the lanfoiffe 

 anda straight edge laid upon ij^when thejplow is bottom 



pr It is usually about y& inch, but may vary slightly 



T 



FIG. 48 THE SUCTION OF WALKING PLOWS SOMEWHAT EXAGGERATED 



without detriment to the plow. It may also be described 

 as the amount the point is turned down to secure pene- 

 tration. 



The point of the share is also turned slightly outward, 

 which makes the line of the landside somewhat concave. 

 The beam of a three-horse plow is in a line with the land- 

 side, but in a two-horse plow it is placed a little to the 

 furrow side of the line of the landside, usually about 3 

 inches, in order that the hitch may be more directly 

 behind the team. For ordinary plows the point of the 

 beam standsi^jnchesjiigh, but it is higher for hard soils. 

 Some bearing must be given at the heel of the share in 

 walking plows, to carry the downward pressure of the 



