CH. v] Ploughing 79 



business to discuss types of implements, but we must 

 deal to some extent with the kind of work thev do. 



The plough consists essentially of two cutting edges, 

 a vertical one called the coulter and a horizontal one 

 called the share, and a curved steel or iron plate called 

 the mould board which turns over the slice of earth as 

 it is cut. The traditional English style of ploughing is to 

 turn the slice without breaking it, so as to form a 

 succession of parallel ribbon-Kke strips over the whole 

 field. On light soils the slice is turned right over so that 

 the surface remains pretty level: thus the surface weeds 

 are buried, and the seeds below the surface have a chance 

 of germinating. On heavier soils, however, while the 

 vegetation is still ploughed in, the slice is left on edge 

 with high crests so as to expose more surface and to aUow 

 more complete penetration of frost and at seeding time 

 a better entrance to the tynes of the harrow. 



In the middle of last century the mould board was 

 modified by the American makers so as to break the 

 slice as it turned over^ : these ploughs were subsequently 

 called "digger" ploughs or Oliver ploughs from a 

 successful maker in the 'eighties. The work done is not 

 so nice looking as in the old English style, but it is 

 probably more effective excepting in a wet season when 

 the surface is liable to be beaten down too much. These 

 different types of furrow-slices are shown in Eig. 22. 



A team of horses can plough three-quarters of an acre 

 to one acre per day on heavy land in England; how- 

 ever urgent the need they can hardly do more. It is 

 obvious therefore that a wet autumn and winter gravely 



^ See an interesting Report in the Transactions of the New York State 

 Agric. Soc. 1867, p. 386. For a more recent investigation see E. A. White, 

 Journ. Agric. Research, 1918, xii, 149-182. 



