traveling with the main valve for the balance of the stroke. This
device will give a remarkably quick opening and a quick cut off, but
in view of the fact that the governor has so much to do, its delicacy
is impaired and a quick response to the demands of the load changing
not so likely to occur. The cut off cannot be as quick as in some
other engines, because the valves are moving in opposite directions,
and while this fact would help, so far as shortening the distance to
be traveled before cut off, the resistance of the valves to travel in
opposite directions, or rather the tendency of the valve to travel
with the main valve, hinders its rapid action.

[Illustration: FIG. 3.]

This is one great objection to the rack and gear operated by the
governor, that two flat valves riding upon each other and sliding in
opposite directions at times require a considerable amount of force to
move them, and as only a slight change in load is required by the
load, the governor cannot handle the work as delicately as it should.
It is too much for the governor to do well. To overcome this
difficulty the Ryder cut-off, shown in Fig. 3, was made by the
Delamater people, of New York. The main slide valve is hollowed in the
back and the ports cut diagonally across the valve to form almost a
letter V. The expansion valve is V-shaped, and circular to fit its
circular-seat. The valve rod of the expansion valve has a sector upon
it and operated by a gear upon the governor stem, which rotates the
valve rod, and the edge of the valve rod is brought farther over the
steam port, thus practically adding lap to the valve. Little movement
is found necessary to make the ordinary change in cut-off, and it is
found to be much easier to move the riding valve across the valve than
in a direction directly opposite. It would require considerable force