A Treatise On Ploughs And Wheel Carriages

k, for keeping the plough at the proper depth and breadth of the furrow, and folid in its motion. Secondly, The breadth from the out land fide fole, to the out fide of the mouldboard fole behind, and the inclination and height of the mouldboard fole, with refpect to the land fide fole. thirdly,' Thirdly, The proper breadth and hir clination of the feather, correfponding to the breadth and inclination of the fole. Firjl then, yith refpect: to the form, of the fole, and the pofition of the fock, which are moft proper for keeping the plough at a proper depth, and folid in its motion. This is a point of the greateft difficulty in the conftrucTion of the plough, and therefore muf t be minutely confidered. Let L M, fig. i. reprefent the bottom of the furrow. As the plough advances, its fore parts and furrow fides are expofed to refiftances. The coulter is prefled down by the earth which it is cutting. The lock is pref- fed down, and alfo a little to the left by the earth which it is raifmg. The fore part of the mouldboard is prefled down, and ajfq to the left by the earth which it is partly raifing, partly fliift- ing to the right, and partly turning o- yer. The hindermoft part of the mould- board is prefled to the left by the earth which it is forcing to the right, and is alfo prefled upwards by the earth which it is turning qver. Thefe Fefiftances, taken together, give to the plough a tendency to thruft the point of the irons deeper into the groun...