22 Of the Coulter.

mortiſed nearly into the middle of the beam, but has a ſhoulder to the land ſide of È an inch. This makes the land fide of the ſheath juſt touch the line A B (fig. 2. No. i.) drawn from the land ſide of the fore end of tlie beam to the land ſide of its other end, and thus the land ſides of the fore end of the beam, of the ſheath, and of the ſtilt, are all in one plane ſurface. This cauſes the coul- ter to clear completely the part of the plough which follows it in the furrow. But when the beam is made in the uſual manner, as in fig. 2. No. 2. the coul- ter does not clear the plough in all the Parts of the land ſide. For, in this caſe, te ne ORE 1) WIr Corelent the land ſide of the ſheath, mortiſed into the middle of the beam, and NK will repre-

ſent