The Middlebury register and Addison County journal. [volume] (Middlebury, Vt.) 1883-1885, 1884-04-11
THE DEADLY FIRE-DAMP.
FREAKS OF GAS THAT MAKES
FEARFUL HAVOC IN THE MINES.
Pee 'liaritics of nm Atmospheric Dyn-
nnitc-Vcthods OF PrecautiDn
Against Explosions.

and then by such terrible catastrophe
as that 1T Pocahontas, in Southwestern
Virginia, has some curious characters
tics. 1t is the sadly picturesque element
! OF the otherwise prosaic business of coal
mining. Its sudden flashes light up the
whole history of this gloomy industry.
Even in the old days when miners were
slaves and their lives of no more account
than those of dogs, the man whose bust
ness it was to clear the mine of fire damp
was an object of romance.
lie was called the 'monk"-becaus of
his costume which was heavy drapery
shrouding his whole fgure-and his duty
was TO 90 along the passages, while the
miners were absent, often crawling on
hands and knees, the better to escape the
gas and thrust Il long pole, at the end of
which a torch was fastened, into the hol
lows in the mine root where the fire damp
gathered. Each little ''pocket" of gas
was fired in turn and thus dangerous
accumulation was avoided. Too often
the charred corpse of the poor "monk"
was found by the miners when they went
to their work next morning, mute testi-
mony that many lives had been saved by
the sacrifice of one.
Sir Humphrey Davy and plain George
Stephenson perfected safety lamps about
the same time, to enable the miner to
work IL the presence of gas, but neither
succeeded beyond a certain point. Sir
Humphrey being famous man, while
George was unknown, his lamp got the
preference, and keeps it to this day. 1t
gives a little more light than Stephen
son's-neithcr of them being much su-
perior in this respect to the traditional
yellow dog'-but Stephensons is the
safer. Miners hate them both, because
of their dimness, and will not use either
of them if they can avoid it. MANY at
tempts have been made to improve on
them, but none have been so successful
as to supersede the "Davy," as miners
call them Unfortunately.
The theory on which this lamp is con-
structed is that flame will not pass
through an aperture of a certain mini
tesimaly small diameter. The fame of
the lamp is inclosed in a cylinder of a
finely woven wire gauze, through which
the gas may pass, to burn within it, but
the flame will not pass out to fire the sur
rounding gas. 1t can be forced out, how
ever, by swinging the lamp, and if there
is much gas in the air, the gauze cylin-
der becomes filled with fame, which
soon burns through the wire, and then,
as the miners say, "otf she goes" That's
how safe the safety lamp is.
There is a curious feature of re-damp
explosions; they do not travel along the
ground. Carburetted hydrogen is lighter
than common air, and will no more stay
at the bottom of mine than a spoonful
of oil will remain at the bottom of
tumblcr of water Hence, there is gen
orally safety streak along the bed of the
gangway, and old miners always throw
themselves in the cutters beside the track
when an explosion comes, if they have
time to do so. 1t is but temporary
refuge, however. The explosion burns
out the oxygen that is in the atmosphere,
and loosely speaking) turns the air to
carbonic acid gas choke damp
which is fifty per cent. heavier than com
mon air and accordingly gathers first in
the gutter. The refugee from the fire
damp must rise before the choke damp
gathers, or he will never rise again; it is
instantly fatal
Pure tire-damp is no more inhammablc
than pure coal gas, to which, indeed, it
bears strong resemblance. An old mine
boss told the writer that he had occa-
sionally ventured into fire damp so strong
that lamp would not burn in it; but
he could not say whether a man could
breath in it or not, for he had never
tried; he had always held his breath
until he came out again. To render it
explosive the gas must be mixed with
not less than eight nor more than four
teen times its bulk of common air.
About eleven is the right proportion to
develop its biggest capacity for mischief
and make it a regular ripper. Touch a
match to this delightful mixture, and,
in the unimpassioned language of science,
sit suddenly expands to 1900 times its
former volume, acquires temperature of
1900 degrees Fahrenheit, and, if CON
fined, eXcrts pressure of 200 pounds to |
the square inch" which, it will perhaps
be admitted, are characteristics sufficient
for respectable explosion.
Another popularity of the miners cy-
clone, and one which helps to explain
some Of the features of the Virginia ex-
plosion, is that it always travels against
'HC W IuNl-lH blIlcT WOTuS, against the |
direction of the air-current. Persons
who are to leeward of the place where
the explosion starts may be sulrocated by
the atter-damp, but they will not be
burned by the fiery gas-unless, indeed,
as is often the case, the explosion has the |
effect of reversing the air current, and a
second explosion follows, in a contrary
direction.
The explanation is, probably, that the
fire runs back along the current of air
that feeds it, as fire started at one end
of train ofpowder will run to the other
end. At the Pocohontas mine the air en-,
tered at the mouth Of the drift and was
drawn out by suction fan at the mouth
of another passage. The force of the ex-
plosion bursted men and timbers out of
the mine and demolished houses a hun
dred yards away. Probably few of the
miners were killed directly by the explo-
sion; the others fell victims to the still
more deadly chokc-damp Philadelphia
Press.