ent another bit of iron that stopped the noise, and during all this
time the fires of seven or eight boilers were burning fiercely, and the
stoker should have checked his fires instead of what he had done; but in
the midst of the carouse all the boilers began to belch forth steam when
the manager came on the scene. The stoker tried to pick off the bits of
iron before the manager could see them, but the steam was to high for
that; and when at last the noise subsided and the steam had cleared
away, the whole of the revellers were on view, caught in a trap, as
there was only one exit. Most of the men were fined or suspended, the
bits of iron were discovered on the levers, and the stoker had a week's
notice to clear out, and lock-up valves were fitted on every boiler and
the keys kept in the manager's desk ever after.

19. _Question._--Can you always depend on the safety-valve lifting when
the steam rises?

_Answer._--I always keep an eye on the pressure gauge, and if I find
that the safety-valve does not lift at the pressure it ought to lift at
I know that the valve is sticking, and I lift the lever and let the
steam out; the cause of the sticking may be that the valve has worn down
in its seat and becomes conical, or there may be a shoulder on the valve
that would cause it to stick, or it may be that the lever and fulcrum
were smeared with oily dirty waste in the process of cleaning and not
wiped off, but left to bake between the parts, which would prevent the
free action of the safety valve.

20. _Question._--Why is the safety-valve lifted at times, especially
when getting steam up?

_Answer._--It is often done by old stokers as well as new ones, and is
more of a silly habit than of trying the pressure of the steam,
especially as there is nowadays a pressure gauge for every boiler in a
stoke-hold. By lifting the safety-valve while steam is in the boiler and
dropping it down again is a dangerous practice; there is a rush of steam
to the valve when lifted, and when it drops the rush of steam is
instantly stopped, and rebounds like an india-rubber ball hit against
the wall, and this commotion within the boiler is likely to blow the
stop-valve to pieces or the manhole cover off. Besides that, there is
always dust floating on the surface of the water, especially in a boiler
just cleaned, and when the valve is lifted the dust is carried up with
the steam, and when the valve is dropped the dust is caught under it and
of