184 Report on Trials of Plows. 



and the edge is kept clear. So when the ground is full of roots, 

 when the coulter is set slanting the roots will slide upward, and 

 the drawing action will cut them; whereas, if the coulter was set 

 at 80 deg. it would draw them out. On the other hand, when 

 used for plowing sod or clover the furrow will be much cleaner 

 when the angle is 75 deg. or 80 deg., as it will not press the 

 grass and roots upwards before they can be cut through. 



There is one rule pretty generally observed in relation to the 

 coulter, both in Europe and America, which is that the land side fticc 

 shall always be parallel to the plane of the land side of the plow. 



Another rule pretty generally adopted is that at the point where 

 the coulter meets the surface of the ground the edge should stand 

 about on(;-quarter of an inch landward of the plane of the land- 

 side of the plow. 



Li the plows made by Prouty & Mears, and those of some other 

 makers, the reverse of this rule is adopted, the coulter being set 

 inwards toward the mould-board about half an inch at the point 

 where the coulter touches the surface, as shown in Fig. 93, and 

 extending from thence landward so that the point of the coulter 

 is vertical over the point 

 of the share. This leaves 

 a small triangle whose 

 base is half an inch and 

 whose altitude is the 

 depth of the furrow to 



cut off by the shin of the Jf'iff. 93. 



plow; this is converted into powder, which rolls over on the face 

 of the furrow slice and covers the grass, which sometimes sticks 

 up in the angle of the slice. 



The vertical elevation of the point of the coulter above the 

 plane of the sole is not well settled. In England it is generally 

 put from one to two inches above, in America from three to four 

 inches above it. 



Then English and Scotch usually put the point of the coulter 

 vertically over the point of the share, but in America it is placed 

 mostly from two to four inches in advance of it. 



We think there is no absolute rule which can be laid down 

 upon these points. The nature of the soil to be plowed will 

 influence the set of the coulter very considerably, and the deter- 

 mination of this part of the trimming of the plow may be safely 

 left to the judgment of the plowman. 



