The Progress. (Shreveport, La.) 1892-1900, 1897-09-04
CURlOS!TlEs OF DRAFT.
How Fire Purifes Air and the Way
Mines Are Ventilated.

How Fire Purtffes Air and the Way
Mines Are Ventilated.
A curious piecesof apparatus used by
Prof. John F. Woodruff, of the New
York teachers college, to illustrate the
principle of ventilation consists of two
lamp chimneys, a tallow candle and the
lid of a pasteboard box. The box lid
has two holes cut in it few inches
apart. The holes are trhe bigger
than the tallow candle. The candle
stands in one hole, the lamp chimneys
stand one over each hole. The object
is to show how the draft of any burning
substance can be made to get rid Of I'M
pleasant odors, foul air, etc. The candle
is lighted and burns in the chimney
which incloses it. If a lighted match is
held at the mouth of the other chimney
the smoke from it will Immediately flow
down the tube and up the chimney 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 car
ries 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 atmosphere, in
order to even matters, supplies more by
way Of the only channel left open to it.
Now, coal mine is freed from its
foul air and new fresh air is drawn into
it in exactly the same way. The en-
trance to some mines arc comparative.
ly small, when the la &c excavations
beneath the surface are taken into con-
sideration. The air in the mine easily
becomes foul, and sooa becomes unfit
for human beings to breathe if some
ventilation is not secured. 1t is only
necessary to have two shafts and to
build fire at the entrance of one OF
them in order to secure the desired re-
suit. If the fire is made to get it's draft
down one shaft and up the 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 dangers of
explosions of fire damp will also be
averted, inasmuch as this deadly gas ia
drawn out and dissipated before it can
collect in sufficient quantity to do dam
age. OF course there are mechanical
contrivances for drawing bad air out
Of mines, but they are not more efficient
than q simple furnace ut the entrance
of a shaft. A striking example of the
value of a fire for the purpose of getting
j
New Castle, Del. It seems that the
Jail was built over sewer which
emptied into the river near by. The
odor from the sewer filled the Jail and
made it very unhealthy place to live
in. The nuisance was abated by build
ing a furnace and smokestack in one
corner of the Jail yard. 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 same nature takes
place when a storm occurs on hot day.
The air in certain spot becomes heat
ed, and in expanding is forced upward,
drawing with it a certain amount OF
moist air from the neighborhood sur
rounding the heated spot. The mois-
furo II, tb;c y ir RI pidly cOndenSeS when