let it be remembered, that in ill-ventilated rooms the carbonic acid is not the only cause of disease. Experiments seem to prove that other matter thrown out of the body, through the lungs and skin, is as truly excrement and in a state of decay as that ejected from the bowels, and as poisonous to the animal system. Carbonic acid has no odor; but we are warned by the disagreeable effluvia of close sleeping-rooms of the other poison thus thrown into the air from the skin and lungs. There is one provision of nature that is little understood, which saves the lives of thousands living in unventilated houses; and that is, the passage of pure air inward and impure air outward through the pores of bricks, wood, stone, and mortar. Were such dwellings changed to tin, which is not thus porous, in less than a week thousands and tens of thousands would be in danger of perishing by suffocation.
These statements give some idea of the evils to be remedied. But the most difficult point is how to secure the remedy. For often the attempt to secure pure air by one class of persons brings chills, colds, and disease on another class, from mere ignorance or mismanagement.
To illustrate this, it must be borne in mind that those who live in warm, close, and unventilated rooms are much more liable to take cold from exposure to draughts and cold air than those of vigorous vitality accustomed to breathe pure air.
Thus the strong and healthy husband, feeling the want of pure air in the night, and knowing its importance, keeps windows open and makes such draughts that the wife, who lives all day in a close room and thus is low in vitality, can not bear the change, has colds, and sometimes perishes a victim to wrong modes of ventilation.
So, even in health-establishments, the patients will pass most of their days and nights in badly-ventilated rooms. But at times the physician, or some earnest patient, insists on a mode of ventilation that brings more evil than good to the delicate inmates.
The grand art of ventilating houses is by some method that will empty rooms of the vitiated air and bring in a supply of pure air by small and imperceptible currents.
But this important duty of a Christian woman is one that demands more science, care, and attention than almost any other; and yet, to prepare her for this duty has never been any part of female education. Young women are taught to draw mathematical diagrams and to solve astronomical problems; but few, if any, of them are taught to solve the problem of a house constructed to secure pure and moist air by day and night for all its inmates.
The heating and management of the air we breathe is one of the most complicated problems of domestic economy, as will be farther illustrated in the succeeding chapter; and yet it is one of which, most American women are profoundly ignorant.
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
