New-York tribune., 1870-04-23
Ne,c York, April ), 1870.
sUPERHEATED sTEAM-A CONSTANT AND TERRI
BILE PERIL.

BILE PERIL.
To the Editor Of The Tribune.
SIR: A few weeks ago six lives were destroyed
by the burning Of the Neponset factory Boston Six
women were roasted alive in loft where they
ployed picking cotton. The Coroners Jury reported
that the OF the fire unknown, there having
fire in the buildng but reference was made to
the that 10000 feet OF onench steamppe was ad-
used beneath the floors Had the Coroner known that
steam pipes sometimes made redhot by superheated
steam at great distances from the boilers the YER
diet might have been different II other persons had
been aware OF this fact when the boilers erected,
the fire might not have occurred. 1t is well known that
when the water is low in boiler as to expose part
OF the heating surface above the water that part be-
hot and the steam OF course becomes as hot
as the iron. Boilers OF steamships having steam
chimney, and meny other boilers now manufactured,
have part OF their heating surface continually
posed above the water, and the steam is,
therefore, liable at all times to heating. That such
boilers do overhead the steam dangerously can be
proven by examination Of the felting with which the
steam-ppes are usually covered when they are 50 50
charcoal Yet elting Is supposed to be incompustl6le
it be charred with any temperature less than
500 degrees degrees OF heat the and seam
the pressure would be about oere hundred pounds the
inch expansive force which no boiler could withstand
But few in could withstand oneuarter Of that
pressure Therefore, If the feltng boiler steam
pipe Is found changed to black charcoal, II Is positive
proof has been Overheated II the boiler is
found intact The felting on boiler Is as frequently
To have exceeded pounds any other cases The
United corvette Alaska set fire few weeks
since from 0verheaed steam, and the worked in
cessantly eight hours to extngush the flames The fire
suspected from smell OF burning cloth which per
after the elting the top OF the boiler burst into flames
The steamer Western Metropolis has made but trip
to ew -Oreans-l6 days steamng-since her boilers
were covered with new felting. She returned to
this port last Sunday, her telling having been on
fire during the return trip, Last Monday The
TRIBUNE had account OF boiler explosion at Balti
more which the blast OF hot steam set fire to the sails
OF vessel lying the building in which the accident
occurred The burning OF the steamer Kennebec on
York River and three destructive in factories and
in each the fire related originated the boilers
IL will be- remembered by many living that the Lex
ington burned on Long Island Sound. II ter
rbe calamity 200 lives having been destroyed but four
escaped of all on board. The fire originated" says the
steam chimney one OF the four persons sayed-a wit
directly opposite the seamchimney; then the
prone made deck. and in some bales OF cotton When
first saw the fire, bucket OF water would have
tngished H. but before the hose could DC prepared all
hopes Of saving the ship were abandoned"
Experiments which were conducted on the steamer st.
Johnlfter the damage from the explosion OF OF her
boilers had been repaired-proyed by the actual app-
cation Of the Thermometer that the temperature OF the
steam would occasionally run up suddenly several
hundred degrees while the water at the proper
ght and that perceptibe increase In the pressure
Of the resulted from the increase OF temperature
IL should be known connection with this subject that
water cannot be heated from the upper surface down
ward. and therefore, even " the steam be highly super
heated. part Of its temperature would be communi
Gated 10 the water below IT, even II the pressure
high aud the steam In actual contact Ii should be known
also. that steam rises IN temperature much more rapidly
than water II OF two boilers Of the capacity
and with equal hre under them Is filed with water and
the other with steam, each starting AT the same tcnpera
ture the water will be heated degree. while the
steam will be heated thousand degrees Hence, IL
posed above the water level the assumes high
temperature quickly While the engine in running. aud
fast II Is generated. the rate of superheatng scarcely
opoefsDie but IN ,he uxu when the nre5 arc banked.