On Agricultural Mechanics. Ill 



either side of it will be equal. This position, then, has the neat- 

 est appearance, while at the same time it answers two most im- 

 portant purposes of ploughing. 



And now with respect to the third object of ploughing, — it is 

 obvious that in order to bury anything effectually, the furrow-slice 

 should as nearly as possible be turned upside down. 



This will be the case when the breadth is great in proportion 

 to the depth, and it will therefore be most perfectly answered 

 when, the breadth being fixed on, the land is ploughed very shal- 

 low. Shallow ploughing too is what experience points out as 

 proper when covering manure ; and it is evident that, provided 

 the manure have sufficient earth above it to absorb the products 

 of its fermentation, its nearness to the surface^ that its decompo- 

 sition may rapidly take place, is an advantage. 



Having now seen what a plough is required to do, we have to 

 consider the form of the implement which shall best effect these 

 objects ; and as a consequence of what we have already said, we 

 must first ascertain what form of plough will do the best work, 

 and then see how this form may be altered to diminish the 

 draught. 



A plough consists of three parts : — 



1st. The frame -work ; 



2nd. The cutting parts ; 



3rd. The mould-board. 



1. The Frame-work. 



The frame -work of the plough must he regulated by the work to 

 he done, so far as strength to sustain the tear and wear and the shocks 

 of the roughest work is considered ; but its dimensions, the length of 

 the beam and the length of the stilts or handles, as they only affect or 

 regulate the power which the man or the horse has over the implement, 

 need not vary with the work to be performed. These are wholly inde- 

 pendent of the consistence of the land to be ploughed, or of the form of 

 the furrow-slice, which both vary, and their dimension may therefore 

 be fixed ; and amidst; the immense variety of forms of the plough, it is 

 satisfactory to know that this point, one so much affecting the appear- 

 ance of the implement, need not vary. 



The length of the beam in some degree affects the power of the horse 

 over the implement. If it be long, it is evident that the straightness of 

 the furrow will be less affected by any deviation of the horse from the 

 straight path, and the motion of the implement will be more regular. 

 This, however, is as well ensured by lengthening the draught-chain as 

 by lengthening the beam. 



The longer the handles of the plough, and the shorter the beam in 

 proportion, the more power will the man have over his implement. 

 There are, however, limits to both of these points, which convenience 

 in the length of the implement impose. Very excellent dimensions are 



