The workingman's advocate. [volume] (Chicago [Ill.]) 1864-1877, 1869-03-27

From ihs Leibers Encyclopedia-
Damps are certain deieterious gasses
which are extricated in mines. They are
distinguished BY miners under the name Of
'choke-damp" and ''6re -damp" The for
mer il found ID the deepest parts Of mines;
il extinguishes candles, and often proves "a
tai when il has been suffered to accumulate
in large quantities. Il consists for The most
part Of carbonic-acid gas. The fre-damp,
which prevails almost exclusively in coal
mines, is mixture Of light carbureted by
drogen and atmospheric air, which explodes
with tremendous violence whenever it comes
IN contact with fame. The injuries which
1 formerly occurred SO frequently, both TO the
machinery and 70 the lives of miners, aris-
Jog from the IRE damp, are now almost
completely be obviated ~ the fne invention
Of Sir Humphrey Davy, the safety lamp.
1t consits Of a cylinder Of wire gause
about for inches in diameter and foot in
length, having double top, secureIylfasteu-
ed BY doubling over to brass rim, which
sc. ~ On to the lamp itself below. The
whole OF the wire cause is protected and
rendered convenient for carrying, by tri-
angular wire frame and ring a. the top.
The wire gauze is made either OF iron or
copper, the wire being at least enc thirtieth
VI al AhSL III IAhHctST uuQ woven kOleLner
80 as 20 leave 625 apertures In a square
inch. The body Of the lamp is Of rive.ed
copper, or Of massy cast brass or cast iron.
the screws lifting so completely as to leave
no aperture 10 the body of the lamp. When
the lamp 10 lighted it affords the miner all
the light which be requires, and renders him
entirely secure, even though entirely envel-
oped with the explosive mixture; which,
with an ordinary light, would Immediately
prove fatal.
Pr ere lie to increase the size and length Of
the fame. When Ne carbureted hydrogen
forms as much as one twelfth Of the volume
Of the air, the gauze cy Under becomes filed
with feeble blue fame, but she fame Of.
the wick appears burning brightly within
the blue harle, and the light OF the wick
augmeDts until the Inhamable gas increases
to one fifth u one sixth, when 1t is Lost In I
the fame Of be are-daEhp, which now fills
the cylinder with pretty trong light. As
long as this explosive mixture Of gas exists
in contact with the Lamp, 20 long twill give
light; and when it 10 extingushed, which
sppens when the foul air constitutes az
much as one third Of the volume Of the as-
mosphere, the air is no longer proper for
respiration for although animal life will
&C atinue when fame Is extinguished, yet it
is always with suffering. A coil Of plati-
nun wire being fixed above the wick Of the
lamp within the gauze cylinder, the metal
continues to glow long alter the lamp Is en-
tinguishcd, and affords sufficient light 10
enable the miner 90 make bis escape
The effect Of the safety lamp is supposed
to depend on the cooling agency Of the wire
gauze, exersed on the portion Of the gas
burning within the cylinder. Hence lamp
may be secure where there ia no cnrrent al
an explosive mixture TO occasion It's beng
strongly heated, and yet MT safe whsn the |
current passes through il with great rapidi- |
IS. But any atmosphere, however explo-
ave, may be rendered harmless K inareas- |
Ing the cooling surface, which may be done |
either BY diminishing the sine of the aper-
lures, Or BY increasing their depth, both of
whioh ore PsEfsosly within the power uf.Sh1I
manufacturer ot The wire galzs.