32 MAINE STATE SOCIETY. 



General Remarks o?i the Form of Plows. 



The form of the mold-board, according to the generally received 

 rule, must be such, that while it tends, like a screw, to invert grad- 

 ually the sod, as it passes onward, it must be neither convex nor 

 concave, when measured by a straight-edge, placed upon it at right 

 angles to the motion of the sod over its surface. • When the straight- 

 edge, while fitting the face of the mold-board, inclines backward at 

 the top, the form assumes the appearance of being convex ; when it 

 inclines forward, the mold-board appears concave. It is better to 

 approach a little towards convexity, as in that case the sod slides 

 more easily over the surface, and the plow is less apt to become 

 clogged with soft and wet earth. 



But independently of the quality just described, there are various 

 Others belonging to the form of mold-boards. The cutting part of 

 the plow may be improperly almost like the square end of a chisel, 

 and the sod may slide backward on a rise, with very slight turn, 

 until elevated to a considerable height before inversion ; this must 

 require more force of the team, and make the plow hard to hold, by 

 nothing to resist the pressure of the sod on the left side. The char- 

 acter of this kind of plow may be quickly perceived by simply ex- 

 amining the mold-board after use ; the scratches, instead of passing 

 around horizontally as they should do, are seen to shoot upward 

 across the face and disappear at the top. 



Instead of this form, the point should be long and acute, and the 

 form such as to begin to raise the left side of the sod the moment it 

 is cut, and before the right side is yet reached by the cutting edge. 

 This turning motion being continued by the mold-board, the sod is 

 inverted without being lifted from its bed ; and the pressure which 

 turns it being opposite to the pressure of the land-side against the 

 unplowed land, an equilibrium of these two pressures is maintained, 

 and the plowman is not compelled to bear constantly to the right to 

 keep the plow in its place. 



S. L. GOODALE, 



J. J. Thomas, 

 J. P. Perley, 

 J. D. Lang, 

 W. C. Hammatt. 



