These instruments are used to stir up, pulverise, and mix together the earth, also to tear up any roots that may be left after ploughing, and to cover up the seed after sowing. The cut represents the usual form of harrow, having a number of iron spikes or teeth attached to frames of which two or more are united together by chains and attached to a bar, that the horses may drag them over the surface of the soil.
Bush-harrows consist of a bundle of brush-wood held together by a pair of frames, and drawn over the soil when it is very dry and light; they are used chiefly to cover up the seed after “drilling.”
ROLLERS.
In clay and other heavy soils, it is necessary after ploughing to break up the large pieces by means of rollers, and in light soils to press it together; for these purposes rollers are used, either with smooth or undulated surfaces, as in the figure; these last form furrows into which the seed falls, causing it to come up in rows. Rollers of a lighter kind are used after mowing to level the surface.
MOWING MACHINES.
FIG. 1.