SCIENTIFIC DOMESTIC VENTILATION



IV.

SCIENTIFIC DOMESTIC VENTILATION.

We have seen in the preceding pages the process through which the air
is rendered unhealthful by close rooms and want of ventilation. Every
person inspires air about twenty times each minute, using half a pint
each time. At this rate, every pair of lungs vitiates one hogshead of
air every hour. The membrane that lines the multitudinous air-cells
of the lungs in which the capillaries are, should it be united in one
sheet, would cover the floor of a room twelve feet square. Every breath
brings a surface of air in contact with this extent of capillaries,
by which the air inspired gives up most of its oxygen and receives
carbonic acid in its stead. These facts furnish a guide for the proper
ventilation of rooms. Just in proportion to the number of persons in
a room or a house, should be the amount of air brought in and carried
out by arrangements for ventilation. But how rarely is this rule
regarded in building houses or in the care of families by housekeepers!

The evils resulting from the substitution of stoves instead of the
open fireplace, have led scientific and benevolent men to contrive
various modes of supplying pure air to both public and private houses.
But as yet little has been accomplished, except for a few of the more
intelligent and wealthy. The great majority of the American people,
owing to sheer ignorance, are, for want of pure air, being poisoned
and starved; the result being weakened constitutions, frequent disease,
and shortened life.

Whenever a family-room is heated by an open fire, it is duly ventilated,
as the impure air is constantly passing off through the chimney, while,
to supply the vacated space, the pure air presses in through the cracks
of doors, windows, and floors. No such supply is gained for rooms
warmed by stoves. And yet, from mistaken motives of economy, as well
as from ignorance of the resulting evils, multitudes of householders
are thus destroying health and shortening life, especially in regard
to women and children who spend most of their time within-doors.

The most successful modes of making "a healthful home" by a full supply
of pure air to every inmate, will now be described and illustrated.

It is the common property of both air and water to expand, become
lighter and rise, just in proportion as they are heated; and therefore
it is the invariable law that cool air sinks, thus replacing the warmer
air below. Thus, whenever cool air enters a warm room, it sinks downward
and takes the place of an equal amount of the warmer air, which is
constantly tending upward and outward. This principle of all fluids
is illustrated by the following experiment:

Take a glass jar about a foot high and three inches in diameter, and
with a wire to aid in placing it aright, sink a small bit of lighted
candle so as to stand in the centre at the bottom. (Fig. 28.) The
candle will heat the air of the jar, which will rise a little on one
side, while the colder air without will begin falling on the other
side. These two currents will so conflict as finally to cease, and
then the candle, having no supply of oxygen from fresh air, will begin
to go out. Insert a bit of stiff paper so as to divide the mouth of
the jar, and instantly the cold and warm air are not in conflict as
before, because a current is formed each side of the paper; the cold
air descending on one aide and the warm air ascending the other side,
as indicated by the arrows. As long as the paper remains, the candle
will burn, and as soon as it is removed, it will begin to go out, and
can be restored by again inserting the paper.

[Illustration: Fig. 28]
[Illustration: Fig. 29]

This illustrates the mode by which coal-mines are ventilated when
filled with carbonic acid. A shaft divided into two passages, (Fig.
29,) is let down into the mine, where the air is warmer than the outside
air. Immediately the colder air outside presses down into the mine,
through the passage which is highest, being admitted by the escape of
an equal quantity of the warmer air, which rises through the lower
passage of the shaft, this being the first available opening for it
to rise through. A current is thus created, which continues as long
as the inside air is warmer than that without the mine, and no longer.
Sometimes a fire is kindled in the mine, in order to continue or
increase the warmth, and consequent upward current of its air.

This illustrates one of the cases where a "wise woman that buildeth
her house" is greatly needed. For, owing to the ignorance of architects,
house-builders, and men in general, they have been building
school-houses, dwelling-houses, churches, and colleges, with the most
absurd and senseless contrivances for ventilation, and all from not
applying this simple principle of science. On this point, Prof. Brewer,
of the Scientific School of Yale College, writes thus:

"I have been in public buildings, (I have one in mind now, filled with
dormitories,) which cost half a million, where they attempted to
ventilate every room by a flue, long and narrow, built into partition
walls, and extending up into the capacious garret of the fifth story.
Every room in the building had one such flue, with an opening into it
at the floor and at the ceiling. It is needless to say that the whole
concern was entirely useless. Had these flues been of proper
proportions, and properly divided, the desired ventilation would have
been secured."

And this piece of ignorant folly was perpetrated in the midst of learned
professors, teaching the laws of fluids and the laws of health.

A learned physician also thus wrote to the author of this chapter:
"The subject of the ventilation of our dwelling-houses is one of the
most important questions of our times. How many thousands are victims
to a slow suicide and murder, the chief instrument of which is want
of ventilation! How few are aware of the fact that every person, every
day, vitiates thirty-three hogsheads of the air, and that each
inspiration takes one fifth of the oxygen, and returns as much carbonic
acid, from every pair of lungs in a room! How few understand that after
air has received ten per cent of this fatal gas, if drawn into the
lungs, it can no longer take carbonic acid from the capillaries! No
wonder there is so much impaired nervous and muscular energy, so much
scrofula, tubercles, catarrhs, dyspepsia, and typhoid diseases. I hope
you can do much to remedy the poisonous air of thousands and thousands
of stove-heated rooms."

In a cold climate and wintry weather, the grand impediment to
ventilating rooms by opening doors or windows is the dangerous currents
thus produced, which are so injurious to the delicate ones that for
their sake it can not be done. Then, also, as a matter of economy, the
poor can not afford to practice a method which carries off the heat
generated by their stinted store of fuel. Even in a warm season and
climate, there are frequent periods when the air without is damp and
chilly, and yet at nearly the same temperature as that in the house.
At such times, the opening of windows often has little effect in
emptying a room of vitiated air. The ventilating-flues, such as are
used in mines, have, in such cases, but little influence; for it is
only when outside air is colder that a current can be produced within
by this method.

The most successful mode of ventilating a house is by creating a current
of warm air in a flue, into which an opening is made at both the top
and the bottom of a room, while a similar opening for outside air is
made at the opposite side of the room. This is the mode employed in
chemical laboratories for removing smells and injurious gases.

The laboratory-closet is closed with glazed doors, and has an opening
to receive pure air through a conductor from without. The stove or
furnace within has a pipe which joins a larger cast-iron chimney-pipe,
which is warmed by the smoke it receives from this and other fires.
This cast-iron pipe is surrounded by a brick flue, through which air
passes from below to be warmed by the pipe, and thus an upward current
of warm air is created. Openings are then made at the top and bottom
of the laboratory-closet into the warm-air flue, and the gases and
smells are pressed by the colder air into this flue, and are carried
off in the current of warm air.

The same method is employed in the dwelling-house shown in a preceding
chapter. A cast-iron pipe is made in sections, which are to be united,
and the whole fastened at top and bottom in the centre of the warm-air
flue by ears extending to the bricks, and fastened when the flue is
in process of building. Projecting openings to receive the pipes of
the furnace, the laundry stove, and two stoves in each story, should
be provided, which must be closed when not in use. A large opening is
to be made into the warm-air fine, and through this the kitchen
stove-pipe is to pass, and be joined to the cast-iron chimney-pipe.
Thus the smoke of the kitchen stove will warm the iron chimney-pipe,
and this will warm the air of the flue, causing a current upward, and
this current will draw the heat and smells of cooking out of the kitchen
into the opening of the warm-air flue. Every room surrounding the
chimney has an opening at the top and bottom into the warm-air Hue for
ventilation, as also have the bathroom and water-closets.

[Illustration: Fig. 30.]

The writer has examined the methods most employed at the present time,
which are all modifications of the two modes here described. One is
that of Robinson, patented by a Boston company, which is a modification
of the mining mode. It consists of the two ventilating tubes, such as
are employed in mines, united in one shaft with a roof to keep out
rain, and a valve to regulate the entrance and exit of air, as
illustrated in Fig. 30. This method works well in certain circumstances,
but fails so often as to prove very unreliable. Another mode is that
of Ruttan, which is effected by heating air. This also has certain
advantages and disadvantages. But the mode adopted for the preceding
cottage plan is free from the difficulties of both the above methods,
while it will surely ventilate every room in the house, both by day
and night, and at all seasons, without any risk to health, and requiring
no attention or care from the family.

By means of a very small amount of fuel in the kitchen stove, to be
described hereafter, the whole house can be ventilated, and all the
cooking done both in warm and cold weather. This stove will also warm
the whole house, in the Northern States, eight or nine months in the
year. Two Franklin stoves, in addition, will warm the whole house
during the three or four remaining coldest months.

In a warm climate or season, by means of the non-conducting castings,
the stove will ventilate the house and do all the cooking, without
imparting heat or smells to any part of the house except the
stove-closet.

At the close of this volume, drawings, prepared by Mr. Lewis Leeds,
are given, more fully to illustrate this mode of warming and
ventilation, and in so plain and simple a form that any intelligent
woman who has read this work can see that the plan is properly executed,
even with workmen so entirely ignorant on this important subject as
are most house-builders, especially in the newer territories. In the
same article, directions are given as to the best modes of ventilating
houses that are already built without any arrangements for ventilation.