Illustration: DRILL.
The drill is used when it is desirable to sow seed in rows at
intervals from each other, so as to give room for the plants to
grow, to free them from weeds and admit air, light, and moisture;
it is a machine which contains the seed for sowing, and at the same
time makes a series of furrows to receive it. There are a great many
varieties of drills, but they act upon the same principle, namely,
that of a cylinder, taking up and pouring small portions of the
seed into funnels so arranged that they shall follow a set of small
coulters forming furrows in the ground, into which the seed falls;
the drill is generally followed by a bush-harrow which covers up the
seed. Some drills have two compartments, one for containing manure,
the other for seed; the manure must be dry and pulverised, such as
ground bones, ashes, &c., which arrangement allows the seed and
manure to be both drilled together, so that the manure shall only be
applied where it is wanted. The cut represents this machine; A A are
portions of the cylinders which are turned round by toothed wheels
attached to the ordinary wheels of the machine, and which can be put
in or out of gear at any time, so as to stop the action of the drill;
B B represent the funnels into which the seed is poured, and C C
the coulters which cut the furrows for the seed. These coulters are
pressed into the ground by means of iron weights attached to the ends
of levers joined to them, and which can be regulated by small chains.