Experimental Inquiry on Dravght in Ploughing. 227 



the usual depth of cultivation^ and I had thought that this might 

 be some disadvantage to the ploughs, but I am informed that, on 

 the contrary, the sohd subsoil Avhen brought up tends to remedy 

 the disposition of this soil to roll onward before the plough, in- 

 stead of falling regularly on the side. This field is as I have 

 mentioned on the Oxford clay formation, which extends in a nar- 

 row belt from about Crewkerne, in Dorsetshire, by Frome, 

 IMalmesbury, Oxford (whence it takes its name), Bicester, New- 

 port Pagnell, running near Bedford, where it becomes wider, and 

 occupies a large space, with Peterborough at its northern end, 

 Huntingdon and Higham Ferrers on its eastern and western bor- 

 ders, appearing again afterwards about Market Deeping, and 

 extending due north by Lincoln, up the Humber. 



If this field be a fair specimen of the toughness of the Oxford 

 clay, we ma,y safely say that, except where it is covered with 

 gravel, the two-horse plough is inapplicable within that district : 

 if it be not, it is desirable to know in what parts of its range this 

 very obstinate clay becomes freer. 



It may be remarked that, if we take the average draught of 

 all the ploughs in each of these trials, we shall find that it was 

 about 18 stone in the first, and in the second 47, much more 

 than double. This variation is within a space of two miles. 

 Horses and men having novv^ had enough to do, returned home. 



Trial III.—A^r. 7. 



It has been mentioned that one main distinction in the trial 

 ploughs lay in the shape of the breast which moves the earth 

 towards the side, that of the Scotch ploughs and of Messrs. Ran- 

 some being a gentle hollow curve, founded on those mathematical 

 principles which were applied by jNIr. Jefferson, President of the 

 United States, in his paper on the true shape of the mould-board, 

 addressed to the French Institute — and, before Mr. Jefferson, by 

 an English ploughwright, at Rotherham, in Yorkshire— and that 

 of the four Berkshire ploughs being full, straight, and short, 

 not raising the mould gradually like a wave, but throwing it over 

 at once. As it is generally stated that the hollow form of the 

 breast is most adapted to sandy ground, I determined on this day. 



very experienced ploughman from the Lothians, could not, in such weather, 

 make any impression on the soil. A third was added, but the team, after 

 struggling for a short distance, was at length brought to a dead standstill ; 

 and the land, which was a wheat stubble, was afterwards broken up with a 

 Kentish turn-wrest, drawn by five horses in line. They, however, did the 

 work well ; but I am persuaded that no swing-plough could have been made 

 to keep an even furrow in such a soil, in the condition stated, — F. Burke. 



