The workingman's advocate. [volume] (Chicago [Ill.]) 1864-1877, 1874-02-14
THE MINER.
The Origin of Coal No. q
All and Ventilation

Atmospheric air is composed for two
gases. Oxygen and nitrogen with the Az
dtuu uf IL small but variable proportion
Xxx a.rbulc acii gas, hit the carbouc acid
is uut necessarily constituent "f the air.
ana y seldom found exceeding $500 part
OF the whole There are also pr-sr,t
more or less aqueous yaper and ammonia,
which are difused throughout IT, oxygen
and nitrogen, NJ which no account is
taken ID amy chemical analysis The COM
position of the atmosphere stands As %
per cent uf oxygen. ana = per cent 81
nitrogen by weight ur n per cent of the
former, ana II per cent 81 the latter BY
volume oxygen Is the most abundant
substance iii nature, forming besides its
proportion IF the atmosphere 80 Ter cent
~ water, ana fully 33 per cent uf the
solid matter, which c1mposcs Tic earth
This gas is the constituent of the air upon
which every form II life and light, ana an
organic substances. are dependant for ex-
isteucr Nitrogen viii neither support
Ffy nor hight, and cannot even bee breathed
mtu the lungs, until it il diluted with oNv-
gel. Neither 81 these gases have taste.
color or smell.
The alr is a vast sea. of which the earth
T. the bottom. Ii extends upward 10 q
hight " about - miles. growing thinner
and more elastic. III the ascendin. column
The bottom 70 the column is pressed ov
the air from the top downward. which
squeezes and contracts il into smaller bulk.
and consequently into greater density At
a hight at 80 miles air Is twice as light
and elastic As 1T the level If the sea AZ
: miles Vt hight it is times as light. and
SO on IN the same proportion, till It ceases
to exist A column of air the whole hight
Vt the atmospheric sea. will weigh nearly
x JIu u the foot square and a column uf
uuc inch square weighs l41 lbs This
weight Is called the pressure IF the atmos-
phure, and 1t is this weight ur pressure
winch when removed. causes the mercury
nv rise ca 80 inches and water to "a feet
az the level Of the sea. The pressure OF
weight II air which supports a man Of 1S5
lbs, Is equal 10 fully - tons.
This pressure Of the atmosphere is in all
directions IA wards, DOWN. ards, sideways,
dIa.onally, etc. Air, IN common with all
GASEOUS bodies, is possessed If the proper
" Of tHtTtt0, which means that it viii not
move when IN a state Of rest, until force Is
applied To start II and keep 1t IN motion
Whenever the pressure Is lessened on any
side Of air, the pressure Of the opposite
side pushes it forward, IL the direction "
the tiues, where the pressure has been re-
moved or. ii artificial pressure be applied
to any side of AIR, a movement takes place
in proportion to such pressure. This move
ment is called wind. Air, IN being heated,
expands l-459th part ~ its volume, ~
Fahrenheit's scale, .or each degree of heat
applied to 1t LOO cubic feet Of air at a
temperature uf - degrees. expands % H.
5U6 feet at PIP degrees. In proportion to
the heat applied, the air becomes lighter,
bulk for bulk, and hies upward, while the
heavy air above resses down and reaches
forward to supply the place Of the displaced
air. Hence, II heat bc constantly applied.
there Wlll be a constant movement Of air
And these are the principles. or natural
laws, "a forces which are used ia causing a
movement Of air throughout coal mines
he ventilation Of mines, means a renew
al If the air, or a constant movement of
air through the mines, for the purpose of
renewing the circulation, and Of sweeping
away the noxIuus, poisonous and intamma-
bic gases which are generated therein. The
first efforts made To renew the circulation,
consisted i'll shaking piece of cloth at the
mouth ut the NINE, which caused a move
ment for a few yards % advance. The fan.
which is perhaps the best ventilatng power
that has ever been brought forward TO as
sist the cereal current, was known to miners
from the earliest times. AgrlCola. who
wrote III the year 1906, relates that the fan
was used IN his time, both for feeding air
forward into the mines. and for exhaustinc
air from the mines the fans b ing driven
sometimes by horsepower, and sometimes
by fall of water.
Steam lets were proposed BY Sir Gold
smith Quincy for the purpose Of producing
a circulating current of air in coal mines.
about the year l848, and many expert
ments were made by English mining engi-
neers with high pressure steam, allowed to
pass through lets 80 Or 40 in number, and \
carried TO the bottom Of the upcast shaft
The main object of this ventilating power
was to displace the ventilating furnace,
which, in fiery mines, sometimes caught
the return air 50 loaded with fire-damp as
to cause an explosion. But after many
contradictory experiments, and great
deal Of cost, 1t was found that steam could
not compete with furnace ventilation, and
the Jets have been abandoned Falls Of
water have unsuccessfully been employed
for the purpose Of creating circulating
stream of air, and have been found to con
tain considerable force, but in most cases
the water has to be pumped out of the
mine again which makes il too expensive
for common use.
One Of the oldest and most common
methods Of providing mines with circulating
currents of air, is by furnace power, which
consists Of erecting furnace at the bottom
Of the upcast shaft, for the purpose Of
purifying the ascending column of air For
deep and extensive mines, the furnace is
perhaps the best, as it is the favorite
method in every mining district in the
world, though in shallow mines Is loses
much Of its force, for the power of the fur
mace is in proportion to the depth Of the
shaft, the power being as the ratio Of the
depth. A deep shaft gives rise to long,
upright column of heated air, and conse-
ouently carses a more powerful ventilating
force. For shallow mines there is no better
ventilatinc power than an exhaust fan,
and those in use in the German mines, in
the davs of Agricola, which consist of
straight. radial vanes, serve good purposes.
The fan of Guibal, of Belgium, has, of late
wears. come into very general use on the
continent of Europe.