228 Report on Trials of Plows. 



dricul and horizontal depressions, are placed one above the beam 

 in front of the coulter, and the other below the beam and behind 

 the coulter. On these the rods rest, fitting into the semi-cylin- 

 drical depressions. When the cutting angle is as above described, 

 the rods are.placed in the middle depression in each plate. If it 

 is desired to vary the angle, so as to make it greater of less, the 

 rods are shifted into corresponding depressions. An iron strap, 

 m, perforated with holes at each end, passes over the projecting 

 ends of these cross-rods, and is screwed tightly against the beam 

 by nuts, which keeps the coulter firmly in the angle in which it 

 has been set. The coulter is kneed inward to the furrow side so 

 as to bring its land-side face nearly into the plane of the land 

 side. 



The reader will observe, on examining the figure of this plow, 

 which we have given al)ove, or, still better, the plow itself in our 

 museum, that the line of the shin or breast varies considerably 

 from any others. Instead of being curved, it is nearly in a straight 

 line; it is a long taper wedge which insinuates itself into the 

 ground very easily; and then, when the slice is once raised into 

 the air, there is a sharp and sudden twist of the wing of the 

 mould-board which breaks it in pieces and completes the pulver- 

 ization. As an illustration of the lifting power of the plow, we 

 may mention that we repeatedly found, on measurement, that the 

 upper edge of the slice, when it was at the extreme point of the 

 wing of the mould-board, was 28 inches above the bottom of the 

 furrow. It may be further observed that this plow, like all those 

 exhibited by Mr. Holbrook, are susceptible of four changes: first, 

 they may be used as sod plows; second, by a change of mould- 

 board, it may be converted into a stubble plow; third, by the 

 addition of a skim plow on the front of the l)eam, it may be 

 changed to a sod and subsoil plow; fourth, by a change in the 

 position of the coulter, it may be made to turn a lap furrow or a 

 flat furrow. 



The Skrm Plow 



Is attached to the land side of the beam by two bolts passing 



through the standard and fastened by nuts on the mould-board 



side. 



The Land Side, Mould-Board and Standard 



Are all cast in one piece, and are braced by a rod running from 

 the rear of the mould-board to the land side cast in the same 

 piece with them. The lower end of the mould-board has a 



