Evening star. [volume] (Washington, D.C.) 1854-1972, 1883-03-10

| From Harper's Weekly
How to get good ventilation either in winter
or summer is q question Of Importance. and
sometimes difficult Question; and its dif1cul-
ties are increased by the darkening of counsel OF
those who sometimes write about it.
The commonest remark we see made about
ventilation is that If YOU open a window from
| the top and bottom the cold air will flow In be-
low and the warm escape above, and that pres
| entity all the air will be changed in this way.
| Now this is true dn-one case and one only-
namely, when the outside air Is but slightly
colder than the inside. Try the experiment on
a cold winter day; the air viii rush in from both
| above and below. Try it on warm summer
| day, when the air within and without Is at the
same temperature; there will be indeed an in
sensible change of air, but not any perceptible
| movement, inward or outward, unless the
| breeze actually blows through the house. Even
q small apartment is not sef-ventilating always
Large buildings, as halls Of Congress. theaters,
churches, require complicated machinery for
| forcing pure air In and for expelling the foul;
but this branch Of the subject need not be dis
cussed here. How shall we best supply pure air
to an ordinary living-room2
The leading points about the winter ventila-
ton of an ordinary dwelling-hou or apartment
| are but two:
!. regulated supply Of pure air from with
2. This cold air should be introduced without
creating draughts.
In all ordinary cases more or less cold air will
come In, whether you wish it or not The mo-
tive power, the inward draught, is due to the
fact that the inside of the house is warmer than
the outside air, so that there is always o strong
| rising current of air which escapes through the
chimney. while the air forces it's way in through
nearly all parts of the building even through the
walls and the roof. All of the materials of an
ordinary house, except the irOn-work and the
glass windows, are pervfous to air, and more so
than is commonly supposed. Pettenkofer shows
that you can blow out candle through dry
brick, If the experiment be managed so as to
concentrate the escaping breath at one point.
square foot of the ordinary iath-and- plaster
ceiling allows the passage Of one and a half
cubic feet per hour Of air at 72o II the air above
be at 400. Look carefully at any old ceiling, and
you can see every joist and lath drawn upon it
In marks a little whittier than the rest Of the
ceiling. The marks show that the wood and
the plaster together are less pervious than the
plaster alone, which has been turned to a darker
tint by the long-continued straining ont of the
Impurities Of the air which passes through It,
Now In what way are we to introduce pure
cold air without creating draughts? II an open
fire Is used, we shall seldom need any special
contrivance; the open fire draws in air by every
opening-through door and window chinks,
through keyholes. through the walls them
selves. Only be sure that the air admitted
comes by clean route, not an unclean one, as
When IL passes through badly ventilated halls,
or from ground surface that may be foul.
The open fire is great yentilator. But stoves
furnaces and hot pipes draw in much less air
from without, aud provide much less chance for
its exit and when these are used we shall be
the better OFT for some opening specially pro-
Vided to admit the outer air. Natural" venti-
ation, like many other natural arrangements,
has great faults; 1T sends the air creeping along
the floor to chill our feet. five make the arti-
fetal opening near the floor, draught upon our
feet is created; ifw make it near the ceiling.
then there is draught upon the head. How
shall we admit cold air in such way that there
Shall be 40 draught at all ? By making the air
current ascend as it enters, rising like a foun-
tain, and then falling like spray until it is
warmed This is easily accomplished by either
of two simple devices.
The first is to tit piece of board three inches
wide Into the bottom OF the window Shut
down the lower sash upon the edge of
this board, and put up the upper sash; that will
leave narrow chink, just three inches deep,
between the two sashes, at the middle Of the
WINDOW Through this opening the air will
pass In, and willbe forced directly upward, like
Fountain toward the ceiling whence It will
diffuse itself through the room without striking
aH one In very cold weather, either remove
the board and make the window tight. or have
some narrow lids attached to the top bar Of the
bottom sash, which you can turn over, and so
cover the openings when necessary. If you
have to guard against smoke or dust without, a
lttIe cOtCOh may De paced between the SasheS
80 as to filter the incoming air; the cotton
should be changed often
The second device consists in making an OPEN
Ing over the door or window into the outer air
In this put piece of board with the inner end
pointing upward. The incoming air is thus sent
upward, as in the case just described The
board should have cheeks or side pieces, to pre-
vent the air from escaping sidewise and down.
ward; 1t should not be put too high, else the
cold air might rebound directly from the ceiling
downward; and 1t should clear the heads of the
occupants. good height is about seven feet
from the floor, unless you chance to have visit
ors who are taller than this. The Sherring-
ham valve" Is this continuance made in iron. and
provided with strings to regulate the proper de-
gree of opening for the valve.
Still another simple and good contrivance
where stove is used Though 1t is a rather I'M
slightly one), is to bring tin pipe about three
inches in diameter from the outer air to point
nearly but not quite over the stove and near the
ceiling. The cool air comes in through this,
and Is warmed and dispersed by the rising
current of hot air from the stove By using
either of these devices the draught will be
avoided, and one may be sure of getting good
ventilation during the coolest weather if he will
pay its necessary price in fuel.
TITUS MUNsON COAN.