On the Draught of Ploughs. 



105 



stubble, naturally light, but then dry and hard. There were two 

 iron ones of the first-mentioned form, weighing 12 stone each ; a 

 wooden one of the second, 10 stone ; an old Welsh plough, 6 J 

 stone ; and also Hart's. In a furrow 5 inches by 9 inches, the 

 draught of Hart's (by Mr. Cottam's plough-gauge), was 13 stone; 

 of the wooden one 17 stone ; the iron ploughs 19 and 20 stone ; and 

 the old Welsh 20 stone. 1 then fitted Hart's wheel to the wooden 

 plough, which it reduced to 14 stone. The difference in the 

 draught of the iron ploughs I think was owing to the share of the 

 lightest being somewhat broader, for in all other respects they 

 seemed perfectly similar. The lightness of Hart's must, 1 think, 

 proceed from its open mouldboard, which reduces the surface ex- 

 posed to friction ; for it cannot be from its full breast, which 

 pushes off the furrow-slice abruptly at its point of separation, 

 where its resistance must be greatest ; and I think the extreme dis- 

 proportion that appeared between the working and surface draught 

 of the old Welsh plough, which you have shown the importance 

 of considering, must have been in some degree owing to its having 

 that form ; for the surface draught was only 4 stone, though in 

 working, as we have seen, it drew 20 stone. The wheel is cer- 

 tainly a great advantage ; for, besides keeping the plough always 

 at the same depth, it greatly lessens its draught, — for much of the 

 plough's weight must be transferred to it from its resisting the 

 tendency the share has to draw the plough downwards. 



But though Hart's plough is very superior in point of lightness 

 of draught; yet for that soil, which w^as firm though light, it was 

 defective in its work, and from the shape of its mouldboarcl I think 

 it would be so in almost every case but that you mention, where 

 the soil is so loose and adhesive, if I may be allowed the expression, ^ 

 that it would cling to and fill up the hollow of the curved mould- 

 board : but as I considered that with an alteration in its mould- 

 board it would make a very excellent plough in most soils (for its 

 fault was that it left the furrow- slice standing on its edge, by 

 which the surface-grass and weeds were not destroyed), I deter- 

 mined to get a mouldboard made for it of the same size and shape 

 as to its length and breadth, but with a sufficient curve to give it 

 a narrow breast and considerable expansion behind. I then sent 

 for one of Ransome's F F ploughs, with which to compare it 

 both in work and draught ; to this I had fixed a light wooden 

 beam and handles, and a single wheel, the same as Hart's. The 

 ground in which I made the next trial was the same as before, but 

 still more dry. The work of Hart's plough was much improved, 

 and it now turned over the furrow-slice quite on its back, and its 

 draught was rather less than with its own mouldboard, w hich I also 

 tried at the same time. I think it gained more by its narrow^ed 

 breast than it lost from the increased friction behind ; nor could 

 I discover any difference in the work of the two ploughs ; but 



