are generally set to throw it from the centre and the result is a
shallow double furrow the width of the machine. By lapping each time
the furrow is partially filled, but to get the land smooth a smoothing
harrow should be used after the rolling cutter.

_Spring-toothed harrows_ (Fig. 55). Spring-toothed harrows with their
curved spring teeth enter the soil readily, draw moderately easy and
pass over obstructions without much difficulty. They are very useful
in new land that is full of roots and stumps and also stony land. They
pulverize the soil to an average depth. They leave the soil in ridges.
The ridges can be leveled by a smoother in the shape of a piece of
plank attached to the rear of the harrow. On newly plowed grass land
they tend to tear up the sod and leave it on the surface. They also
tend to drag out coarse manures when plowed in.

The original and more common form of the spring-toothed harrow is a
floating harrow when at work. That is, it rests on the points of the
teeth and is dragged or floated over the ground. A newer form of
spring-toothed harrow, sometimes called the fallow cultivator, is
mounted on high wheels and its action is largely controlled by them.
This form of harrow is claimed to do much better work than the
floating harrow and may in a large measure displace the rolling
cutter. The weight of this harrow is entirely taken from the soil
except in the wheel tracks, and the entire action is that of
pulverizing and lightening the soil.

_Spike-toothed harrows_ (Fig. 56). The teeth of these harrows are
round, square or diamond-shaped spikes fastened into a wood or iron
frame. The teeth are set in a vertical position or are inclined to the
rear. These harrows are shallow in their action; they run easily but