36 



BRITISH HUSBANDRY. 



[Ch. III. 



being drawn lengthwise between the riHges, thus press into the furrow, and 

 partly, though not always effectually, accomplish the object ; for the power 

 of this roller is chiefly exerted under its greatest diameter, where the soil, 

 being in general the most crumblv, is the least in want of its influence. We 

 have lately seen it in the hands of a very intelligent farmer, who occupies 

 land of such a heavv nature as to require it to be thrown into very raised 

 ridges, and he uses it attached to the front of a double roller, between which 

 it acts in the following manner, the length, or breadth, of the entire ma- 

 chine being equal to cover a twelve-bout land — six on each side, — but, 

 although drawn bv horses, thev are attached in single shafts to avoid 

 poaching the land, and thus walk in the furrow. 



''^^>- 



CONCAVE ROLLERS, 



of the same description as that sketched underneath, are, on the contrary, 

 used chiefly for the purpose of equally compressing the crowns of the 

 ridges, in which form they are certainly effectual when employed upon 

 land which is laid into very narrow ridges of a convex shape ; but they 

 must be then made the full width of the ridge, as they are evidently useless 

 upon level ground. 



SPIKY ROLLERS 



are not unfrequently employed to crush the clods upon tenacious soils 

 which break up in large lumps, and, if the land be dry, they are good 

 instruments ; but if it be moist, they clod uj) with the earth between 

 the spikes with which they are studded, and thus become of less use 

 than those which are plain. To remedy this defect, however, a great im- 



