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 vititates 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 side
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: An illustration of a glass bottle with a burning
candle set inside it and a piece of paper propped in its neck. Arrows
show the direction of the circulation of air into and out of the
bottle.]
This illustrates the mode by which coal-mines are ventilated when
filled with carbonic acid. A shaft divided into two passges, (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.
 [Illustration: A diagram showing the circulation of air into and out
of a mine shaft.]
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 cars 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 flue, 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 flue for ventilation, as also have the bath-room and
water-closets.
[Illustration: An illustration of a chimney, with arrows indicating
the circulation of air.]
 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 work-men 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.
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