reversing lever into full forward gear, the petroleum and steam are shut
off from the spray injector, the ash-pan doors are closed, and if the
incline be a long one, the revolving iron damper over the chimney top is
moved into position, closing the chimney, though not hermetically. The
accumulated heat is thereby retained in the fire-box; and the steam even
rises in pressure, from the action of the accumulated heat alone. As soon
as the train reaches the bottom of the incline and steam is again
required, the first thing done is to uncover the chimney top; then the
steam is turned on to the spray injector, and next a small quantity of
petroleum is admitted, but without opening the ash-pan doors, a small fire
being rendered possible by the entrance of air around the spray injector,
as well as by possible leakage past the ash-pan doors. The spray
immediately coming in contact with the hot chamber ignites without any
audible explosion; and the ash-pan doors are finally opened, when
considerable power is required, or when the air otherwise admitted is not
sufficient to support complete combustion. By looking at the fire through
the sight hole it can always be seen at night whether the fire is white or
dusky; in fact, with altogether inexperienced men it was found that after
a few trips they could become quite expert in firing with petroleum. The
better men contrive to burn less fuel than others, simply by greater care
in attending to all the points essential to success. At present
seventy-two locomotives are running with petroleum firing; ten of them are
passenger engines, seventeen are eight-wheel coupled goods engines, and
forty-five are six-wheel coupled. As might be expected, several points
have arisen which must be dealt with in order to insure success. For
instance, the distance ring between the plates around the firing door is
apt to leak, in consequence of the intense heat driven against it, and the
absence of water circulation; it is therefore either protected by having
the brick arch built up against it, or, better still, it is taken out
altogether when the engines are in for repairs, and a flange joint is