lengthened the next time the Engine is in the repairing shops. A
deficiency of weight on the front or hind wheels is indicated by the
pitching of the Engine, and should be remedied in a similar manner.

The regulator should be gradually and completely closed, when the Engine
or train pitches or rocks violently,--in passing a series of points and
crossings,--in very sharp curves, especially if double,--in rough parts
of the permanent way,--and in descending planes whose inclination is
sufficient to carry the train down, without steam, at a velocity of 30
miles per hour. In descending such an inclined plane, if it should be
found that the velocity is greater than 30 miles per hour, it should be
reduced by gently applying the break.

On every Railway there is a prescribed limit to the pressure of the
steam, and no circumstance should induce the Engine-man to use steam at a
higher pressure, or in any case to weight the lever, or hold it down for
more than a moment. When there are two safety-valves, that which is out
of reach may be set at the limit of pressure, and the valve next the
foot-board some pounds lower. It is an advantage to have a stop placed
below the lever of the safety-valve on the screw of the spring balance,
to prevent its being inadvertently screwed down to more than the working
pressure.

The steam whistle is obviously intended to give notice of danger: on this
account its use is forbidden on some Railways, excepting on occasions of
extreme emergency; but the variety of modulation of which it is
susceptible has in others induced its adoption as a frequent warning.
When the latter is the case, it has been found a safe measure to sound
the whistle directly the steam has been shut off previously to stopping
at a Station, and to give two short whistles the moment before starting,
to warn parties of the approach and departure of the train. When this
system is practised, the Engine-man should not turn on the full power of
the whistle, but reserve it exclusively for cases of danger.

When near the end of the trip very little fire is wanted, and both
feed-pumps should be turned on for a short distance before arriving at
the Station, unless the Engine is to start again immediately. If it is
intended to remain at the Station about an hour, the water should be
considerably above the middle cock (when the Engine is standing), which
will be effected by keeping on both feed-pumps from a half to
three-quarters o