type shown in Fig. 24 works faultlessly in practice.

[Illustration: Fig. 27.]

One plan (Pat. 346,030), designed to combine the advantages of a direct
acting motor and an oscillating shaft, mounts the whole machine, motor
and all, on a rocking frame. The spindle is of course in fixed bearings
in the frame. However, the plan is not practical.

[Illustration: Fig. 28.]

In driers the direct acting engine has many advantages over the belt.
The atmosphere is always very moist about a whizzer, and there are
frequently injurious fumes. The belt will be alternately dry and wet,
stretched and limp, and wears out rapidly and is liable to sever. In
all machines in which the shaft oscillates, if the center of
oscillation does not lie in the central plane of the belt, the tension
of the latter is not uniform. This affects badly both the belt and the
running. A reference to the various figures will show the best position
for the pulley.

The greatest difficulty experienced with belting is in getting up speed
and stopping. The basket must not be started with a sudden impulse. Its
inertia will resist and something must give way. A gradual starting can
be obtained by the slipping of the belt at first, but this is
expensive. The best plan is to conduct the power through a species of
friction clutch--an iron disk between two wooden ones. This has been
found to work admirably.

BRAKES.--The first centrifugals had no brakes. They ran until the