at the Bristol Meeting in 1842. 357 



The action of the plough was in no respect deranged by that of 

 the slicers; it '^swam fair" on the furrow bottom, leaving it 

 clean and flat, and required so little skill in guidance, that Mr. 

 John Stokes, of Pauntley Court, the exhibitor, who held the 

 plough, frequently left it free for a long space to follow the 

 horses. It possessed, therefore, like other well-constructed wheel - 

 ploughs, those properties approaching to self-action, and govern- 

 ment, which must be acknowledged to be no less essential to 

 the perfection of an agricultural implement than to the steam- 

 engine, the lathe, and machinery of all descriptions. It has 

 been noticed that the great amount of pulverization effected by 

 this simple combination of two knives with the common plough 

 was obtained at the comparatively slight additional cost of 15 per 

 cent, of animal force ; the whole draught of the plough, in this 

 state, not exceeding that of several other good ploughs in the 

 same soil, and being within the compass of the power of two 

 horses. The judges were of opinion that the soil operated upon 

 was as well pulverized by this single process, and to as great a 

 depth, as if first ploughed and then harrowed ; and they trust that 

 subsequent experience may justify the expectations formed on the 

 ground, that, by means of this remarkably simple combination, no 

 unimportant economy and advantage may accrue to the farmer in 

 pulverizing turnip and other soils preparatory to drilling the 

 seed. 



Fig. 2, drawn to a scale of I inch to the foot, represents the 

 tail -part of the plough, and shows the knives a a in their working 

 position. A furrow slice, 6 inches deep by 10 inches wide, 

 would, if composed of perfectly coherent and elastic materials, 

 assume the shape shown in section at c. Such, however, never is 

 nor can be the case in practice with soil of any description. The 

 slice of earth operated upon by a plough, whilst being raised from 

 its horizontal bed, and forced into its new and oblique position 

 by the torsion of the mould-board, is irregularly extended, and 

 much loosened, or broken, owing to the imperfect cohesion of its 

 particles, and to the absence of elasticity. It would, therefore, 

 appear that the instant seized, and the place chosen, for assisting 

 in the further disintegration of the slice by the action of the 

 knives, are precisely those when its existing condition permits the 

 greatest amount of ]>ulverization to be effected, and with the least 

 expenditure of power. The crumbling effect produced by sever- 

 ing each slice in detail, before it is pressed by the succeeding 

 slices into a compact mass, and left to dry and harden, is 

 analogous to the manipulations of the gardener, who bruises and 

 pulverizes each spadefuU of earth as he throws it up from the trench, 

 and thus spares himself much subsequent toil, and his work 

 much injury, by diminishing the after labouring and trampling 



