The Columbia herald. [volume] (Columbia, Tenn.) 1850-1873, 1870-06-03

4aA1~H 0VxeuoCs
The word ventilation is derived
from tho Latin word Ventito, to blow,
or fan, and signifies the renewal of
fresh sir. There is always the same
pcrpet1mlIn motion of air in an occupied
room as in that out of doors-always
two currents, one Of hot air, flowing
out of the room, and another flowing
into the room. We ascertain this to
be a fact by The following expert
ment: If lighted candle be held near
the crevice at the top of the door, the
flame will be blown outward toward
the nall; but If the candle be held at
the bottom of the door, the fame will
be blown inward, that is, into the
room. This, however, is not the case
if fire be in an open fireplace in the
room, for when fire is lighted an in
ward current is drawn through all the
crevices.
The fame of the candle is blown
outward, if the candle be held at the
Top of The door, because the air
of the room being heated, and,
consequently, rarified, asceuds, and,
floating about the upper part of the
room, some of it escapes through the
Acrevice at the top of the door, produc-
ing the current of air outward. And,
the flame is blown inward because a
martial vacuum is made at the bottom
of the room as soon as the warm AIR
of the room has assembled to the cell
inc or made its escape from the room,
and cold air from the hall rushes un-
der the door to supply the VOID.
"a vacuum" means place from
which the air has been taken, and
partial vacuum " means, OF course, a
place from which part OF the AR has
been taken. Thus, when the air near
tbe door ascends to the ceiling par
tiaI vacuum is made near the floor
This vacuum is filled up by colder
air. which rushes under the door and
through the aindow crevices into the
room. As an illustration: If pail
he dipped into pond, and filled with
water, a hole Tor vacuum) is inade III
the pond as large as the. pail; but the
moment the pail is drawn out, the
vacuum is filled by the water around.
Now, TO apply the illustration: The
heated air which ascends from the
bottom of The room is removed like
the water i'm the pail; and. as the void
was instantly supplied by the air
around.
A room. even without fire, is gen.
erally warmer than the open arr, BE-
cause the air in the room is not snb-
iect to much change, and soon be-
comes of the same temperature as our
skin. when it no longer feels cold.
We generally feel colder out OF
doors than in doors, because the ar
which surrounds us ont of doors is
always changing; and as fast as one
portion of air has become warmer by
contact with our body, another cod
norton surrounds us to absorb more
heat.
There is generally strong draught
through the kcyhole of a door, be-
cause the air in the room we occupy
is warmer than the air out of doors !:
therefore, the air rushes through the
kephole into the room, and causes a
draught.
And there is, also, a strong draught
under the door, and through the Gre
vice on each side, because cold AIR
rushes from the hall to supply the
void i'm the room caused by the escape
of warm air up the chimney and
through the crevices in the upper
parts of the door.
If YOU open the lower sash of WIN
dew there is more draught than IL
YOU open the upper sash-the reason
of which is this: If the lower SSH be
omen. cold external air will rush free
Nv into the room, and cause great
draught inward but if the upper sash
be omen the, heated air will rush out,
|, and of course there will be less
Z draugbt inward. A room is better
ventilated by opening the upper sash,
because the hot, vitiated air (Wmch
always ascends towards the ceiling)
can escape more easily. A hot room
is cooled more quickly by opening the
lower sash, because the cold air can
lter more freely at the lower part OF
the room than at the upper.
The hottest place in a church or
theatre is the gallery, because the
heated air of the building ascends, ana
all the cold air which can enter at the
doors and windows keeps near the
floor till it has become heated.
Mines are ventilated by being FUR
uisbed with two shafts, or fiucs, which
are SO arranged that air forced down
one shall travel the whole extent oil
the mine before it escapes by the 9th,
CIR. By keeping up fire in one OF
these shafts tue air is rarified or eX-
banded within, causing an ascending
current, carrying with 1t all the noX'
ious gases, aud rendering the air pure
Rarefaction makes the air lighter
causing it to ascend through the cold
err strata, as cork put at the bottom
of a basin of water rises to the sur
face.
Stoves should be fixed as near the
floor of a room as possible, i'll or.
der that the air in the lower par
of the room may be heated by inc
fire. The air in the lower part of the
room would not be heated equal!
well if the stove were more elevated
because the heat of a fire has very ut
lie effect upon the air below the leve
of the CRATE; and, therefore, every
crate should be as near the floor a:
possible.
The reason that our feet are fire.
oueptly cold when we sit close by 6
good fire, is because, as the fire con
sumes the air which passes over 1t
cold air rushes through tie crevice'
of the doors and windows, along the
floor of the room, to supply the def
cheney. and these currents ofcold all
rushing constantly under our feet, de-
prive them of their warmth.
Smoke is small particles OF carbon
Sc, arated by combustion from tho
fire, but not consumed.
Smoke and steam curl as they as.
cend. because they ere forced round
bv the ascending and descending cur
rents of air.
Some chimneys smoke because fresl
air is not admitted into the room al
fast as it is consumed by the fire; il
consequence of which current OF all
rushes down the chimney to suppl!
the deficiency, driving the smoke
along with it.
The air will come down the chin
ney because it can get into the room
i'm no other way, if the doors an6
windows are all made air-tight. Tht
best and spcediest remedy in such
case is to open the door; but by fal
the best remedy is TO carry small