The Locomotive - Lighthouse Survival Blog

56 THE LOCOMOTIVE. [April,
sious arise from the occurrence of the spheroidal state, we see that all the heat contained
in the metals all of its potential thermal energy when converted wholly into mechanical
energy — barely suffices to heat the water introduced into the boiler up to the tempera-
ture corresponding to an effective pressure of an atmosphere and a half. It follows that
if, as in the case we have considered, the pressure is already greater than this, the intro-
duction of cold water will cause it to fall.
" This same conclusion was reached by tlie engineers of the Pennsylvania Railroad,
who tried to bring about an experimental explosion by injecting cold water into the
boiler of a locomotive whose crown-sheet was dry and red hot. The cold water had
hardly been introduced when the pressure fell, and naturally the explosion did not take
place, though the furnace had been so highly heated that it was afterwards useless.
"In the monthly report for December, 1882, of tlie Chief Engineer of the Manchester
Steam Users Association, which association has been studying steam boilers for twenty
years with a view to securing safety and economy in the use of steam, there is quoted
the following opinion of an ' expert' concerning the exjjlosion of a locomotive:
" 'After a careful examination of all the circumstances accompanying the explosion,
I can give no other opinion than that it was due to the instantaneous formation of steam
at high pressure, which acted with irresistible force on the furnace and boiler, the pro-
duction of steam being so copious that neither the safety-valve nor the main steam pipe
(which was probably open, since the locomotive was in motion) could discharge it.
Explosions similar to this one, and which could be explained only by assuming a Kudden
generation of steam at high pressure, have occurred before; the most notable one being
that of a locomotive belonging to the Caledonian Company, which exploded while run-
ning at a velocity of thirty miles an hour, near Carlisle, in April, 1856.'
"To this opinion Chief Engineer Fletcher replied: ' Such a conclusion is contrary
to the experience of the Manchester Steam Users Association. The association has carefully
studied a large number of explosions which have occurred during the past twenty
years, and has found that such catastrophes result uniformly from simple and preventa-
ble causes. The report in question is a step backwards, and tends to shroud boiler
explosions in mystery.'
" We may also refer to a recent report of Chief Engineer Fletcher concerning some
experiments made by his company on the effects of red-hot furnace crowns. The Man-
chester Association dissents from the opinion commonly exjjressed concerning the effect
of showering water on red-hot crown-sheets, and considers this opinion to be quite erro-
neous, although it seems to be profoundly rooted in the minds of the industrial and
technical public.
"A few years ago an extremely disastrous explosion occurred in a dockyard of the
British navy. The true cause of the explosion was corrosion of the shell-plates, which,
in some places, were thinned down almost to the thickness of paper. However, three
experts were on hand who, at the inquest, referred the explosion to lack of water. The
tireman had neglected his duty, had let the water-level go down in the boiler, and had
turned the feed on suddenly; then an enormous pressure was suddenly produced, so
much greater than the normal pressure as to fracture the shell and bring about the ex-
])losi