Chapter 4 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.