00 H.P., with cylinders in duplicate of 46 inches and 86 inches
diameter, and 3 feet 3 inches stroke, running 100 revolutions per minute.
An examination of the indicator diagrams taken from these engines shows
that no wire-drawing takes place, and that, though the expansion is
carried to a point beyond the ordinary requirements, the compression is
but slightly increased. In all the diagrams taken from this valve motion
there is seen the clear, full upper line showing an abundant admission of
steam without any wire-drawing, and also the distinctly marked points
where "cut-off" or "suppression" and where "release" takes place, showing
the rapid action of the valves at those points.

It is well known to engineers that to obtain the maximum advantage out of
compounding, it is necessary to cut off in the low pressure cylinder at a
point corresponding to the relation between the low and the high, and that
point should be unaltered, whereas the point of cut-off in the high may at
the same time be varied to suit the work to be done.

In an ordinary link motion engine (where both links are connected to the
same weigh shaft), when linking up the high pressure cylinder to cut-off
short, the same change is necessarily made in the low. By the use of the
Joy gear, cut-off valves may be fitted to both cylinders, that for the low
pressure being fixed at the constant position required by the proportion
of the cylinders, while that on the high is adjustable; of course, in this
case, the position of the quadrants must be only changed for reversing. In
arranging the independent cut-off on the Joy gear, it is only necessary to
increase the length of the vibrating link beyond the point of attachment
for the main valve spindle connection to obtain a point from which motion
may be taken to actuate the cut-off valve; even then the cost of the Joy
gear for both cylinders is but little more than for a single set of link
gear.

This arrangement gives an absolutely perfect distribution of steam for
compounding, also equalizes the power developed by both cylinders, and is
far more simple and inexpensive than any other gear in existence.

* * * * *

THE STEAM BELL.

[Illustration: FIG. 1.]

[Illustration: FIG. 2.]

The secondary railways in rural districts in Austria having no gates or
bars at the level crossings, or guards at such points, but being open like
tramways, special precautions are required to