or. This is shown on a larger scale at A
(Fig. 50). At the left of the worm gear is a bevel gear driving the
spindle D of the governor, and at the right an eccentric which gives a
vibratory motion to the lever F. The crank C upon the end of the shaft
operates the oil pump. The speed of the turbine is controlled by
admitting the steam in puffs of greater or less duration according to
the load. The lever F, having its fulcrum in the collar surrounding the
shaft, operates with each vibration of the eccentric the pilot valve.
The valve is explained in detail later.

[Illustration: FIG. 50]

This form of governor has been superseded by an improved type, but so
many have been made that it will be well to describe its construction
and adjustment. The two balls W W (Fig. 50) are mounted on the ends of
bell cranks N, which rest on knife edges. The other end of the bell
cranks carry rollers upon which rest a plate P, which serves as a
support for the governor spring S. They are also attached by links to a
yoke and sleeve E which acts as a fulcrum for the lever F. The governor
is regulated by means of the spring S resting on the plate P and
compressed by a large nut G on the upper end of the governor spindle,
which nut turns on a threaded quill J, held in place by the nut H on the
end of the governor spindle and is held tight by the lock-nut K. To
change the compression of the spring and thereby the speed of the
turbine the lock-nut must first be loosened and the hand-nut raised to
lower the speed or lowered to raise the speed as the case may be. This
operation may be accomplished while the machine is either running or at
rest.

The plate P rests upon ball bearings so that by simply bringing pressure
to bear upon the hand-wheel, which is a part of the quill J, the spring
and lock-nut may be held at rest and adjusted while the rest of the
turbine remains unaffected. Another lever is mounted upon the yoke E on
the pin shown at I, the other end of which is fastened to the piston of
a dash-pot so as to dampen the governor against vibration. Under the
yoke E will be noticed a small trigger M which is used to hold the
governor in the full-load position when the turbine is at rest.

The throwing out of the weights elevates the sleeve E, carrying with it
the collar C, which is spanned by the lever F upon the shaft H. The
later turbines are provided with an improved form of governor operating
on the same principle, but embodying severa