The Marietta journal. [volume] (Marietta, Ga.) 1866-1909, 1897-10-07
CURiOSlTlES OF DRAFT.
How Fire Pnrifies Air and the Way Mine
Are Ventilated.

| HOW Flre EUrines Air and the Way Mines
| Are Ventilated.
A curious piece of apparatus used
by Professor John f. Woodruff of
the New York Teachers college to
illustrate the principle of ventilation
consists of two lamp chimneys,
tallow candle and the lid of a paste
board box. The box lid has two
holes cut in it a few inches apart.
The holes are a trifie bigger than
the tallow candle The candle
stands in one hole. The lamp chin
neys stand one over each hole.
The object is to show how the draft
of any burning substance can be
made to get rid of unpleasant doors,
foul air, ETC. The candle is lighted
and burns in the chimney which in
closes it. If lighted match is held
at the mouth of the other chimney,
the smoke from it will Immediately
flow down the tube and up the chin
ney in which the candle is burning.
This is because the lighted candle
gets its draft through the other
chimney, and the air rushing down
one and up the other carries the
smoke from the match along with
it. The reason the air does this is
because the heat Of the candle flame
expands the air in the one chimney
and forces it upward. The atmos-
phere, i'll order to even matters,
supplies more by way of the only
channel left open to it.
Now, coal mine is freed from it's
foul air, and new, fresh air is drawn
into it in exactly the same way.
The entrance to some mines is COM
paratively, small when the large ex-
cavations beneath the surface are
taken into consideration. The air
in the mine easily becomes foul and
soon becomes unfit for human be-
ings to breathe if some ventilation
is not secured. 1t is only necessary
Il
fire at the entrance of one of them
in order to secure the desired result
Ii the fire is made to get it's draft
down one shaft and up tho other, as
in the case of the lamp chimneys,
all of the foul air will be drawn out
of the mine, and a corresponding
quantity of fresh air will be drawn
in. The danger of explosions of
fire damp will also be averted, mas
much as this deadly gas is drawn
out and dissipated before it can col
lect in sufficient quantity to do dam
age. OF course there are mechanical
contrivances for drawing bad air
out of mines, but they are no more
efficient than a simple furnace at the
entrance of shaft. A striking ex-
ample of the value of q fire for the
purpose of getting rid of foul odors
is afforded in a Jail in Newcastle,
Del. Itseems that the Jail was built
over Il sewer which emptied into the
river near by. The odor from the
sewer filled the Jail and made it a
very unhealthy place to live in.
The nuisance was abated by build
ing a furnace and smokestack in
one corner of the jailyard. A hole
led down from the furnace to the
sewer pipe. When the fire was
lighted, the bad air in the pipe was
drawn up by the fire and sent out of
the stack many feet above the Jail.
Something of this nature takes
place when n storm occurs on a hot
day. The air in a certain spot be-
comes heated and in expanding is
forced upward, drawing with it
certain amount of moist air from
the neighborhood surrounding the
heated spot, The moisture in this
air rapidly condenses when it reach
es the cooler strata above, and, turn
ing to water, descends to the earth
again in the form of shower. At
lanta Constitution.