20 Effort on Trials of Plows. 



Fig. 7 is the share turned bottom upward, showing concavity o 

 of the fin, which must be greatest in a stony, rubbly soil. 



Fig. 8 shows the share right side upward, but leaning towards 

 the left. 



Fig. 3 shows the upper and right side of a four coultered plow, 

 of which V, the iron ground wrest, is shown in Fig. 9; it is two 

 feet five inches long, four inches deep at the end b, and three- 

 eighths inch thick, except at the end a, where it is thin enough 

 to bend so as to set close to the share, as at e, fig. 6. The ground 

 wrest has four small holes near its end, a, into one of which a nail 

 is inserted, which fastens it to the sheat through the long hole in 

 the side of the socket of the share, as at a, fig. 10, when it will 

 stand in the position ef in fig. 6. From the outside of the ground 

 wrest at y, to the outside of the share at 6, is eleven and a half 

 inches. The ground wrest has several holes at the upper side of 

 its broadest end, as at 5, in fig. 9, by which it is nailed to the 

 lower part of the drock T, as in fig. 3, which drock, with its per- 

 forations, is shown in fig. 11 



Fig. 12 is the earth board (mould board), with its inside up- 

 wards; the notch a b shows the rising of the wood which take^ 

 hold of the sheat, to Avhich it is fastened by the holes c and d, 

 and at the other end it is fastened to the drock by the hole e; all 

 which is seen at W, in fig. 3. The pin with which it is fastened 

 to the drock is larger in the middle than at either end, which 

 prevents the earth board from coming near the drock; by this pin 

 the distance between them is regulated, so that the rear end of 

 the earth board may be thrown inward or outw^ard, according to 

 the requirements of the soil. 



Fig. 13 is the long handle, five feet four inches long, and four 

 inches in the widest part; it is pinned to the sheat through the 

 holes a 6, and to the drock through the hole c. 



The short handle, S, is fig. 14; is three feet nine inches long, 

 and is pinned to the hinder sheat, fig. 15, by the hole a, and to 

 the top of the fore sheat above the beam by the hole b. 



Fig. 16 is the piece for the mortises in which the coulters are 

 inserted; the lateral distance between them is two and a half 

 inches. The fore part of every mortise should incline a little to 

 the left, so that the backs of the coulters may not bear against 

 the lett side of the incisions made by their edges. In setting the 

 coulters, each should stand nearer to the perpendicular than the 



