Popular Education / For the use of Parents and Teachers, and for Young Persons of Both Sexes

by Ira Mayhew

The ordinary facilities for ventilating school-rooms consist in opening a door and raising the lower sash of the windows. The only ventilation which has been practiced in the great majority of schools has been entirely accidental, and has consisted in opening and closing the outer door as the scholars enter and pass out of the school-house, before school, during the recesses, and at noon. Ventilation, as such, I may safely say, has not, until within a few years, been practiced in one school in fifty; nor is it at the present time in many parts of the country. It is true, the door has at times been set open a few minutes, and the windows have been occasionally raised, but the object has been either to let the smoke pass out of the room, or to cool it when it has become too warm, not to ventilate it.

Ventilation by opening a door or raising the windows is imperfect, and frequently injurious. A more effectual and safer method of ventilation consists in lowering the upper sash of the window. In very cold or stormy weather, a ventilator in the ceiling may be opened, so as to allow the vitiated air to escape into the attic, in which case there should be a free communication between the attic and the outer air by means of a lattice in the gable, or otherwise. A ventilator may also be constructed in connection with the chimney, by carrying up a partition in the middle, one half of the chimney being used for a smoke flue, and the other half for a ventilator.

But it is often asked, Why is it not just as well to raise the lower sash of the windows as to lower the upper one? In reply I would say, first, lowering the upper sash is a more effectual method of ventilation. In a room which is warmed and occupied in cold weather, the warmer and more vitiated portions of the air rise to the upper part of the room, while that which is colder and purer descends. The reason for this may not be readily conceived, especially when we consider that carbonic acid, the vitiating product of respiration, is specifically heavier than common air. Three considerations, however, will make it apparent. 1. Gases of different specific gravity mix uniformly, under favorable circumstances. 2. The carbonic acid which is exhaled from the lungs at about blood heat is hence rarefied, and specifically lighter than the air in the room, which inclines it to ascend. 3. The ingress of cold and heavier air from without is chiefly through apertures near the base of the room. Raising the lower sash of the windows allows a portion of the purer air of the room to pass off, while the more vitiated air above is retained. Lowering the upper sash allows the impure air above to escape, while the purer air below remains unchanged.

Lowering the upper sash is also the safer method of ventilation. It not only allows the impure air more readily to escape, but provides also for the more uniform diffusion of the pure air from without, which takes its place through the upper part of the room. The renovated air will gradually settle upon the heads of the scholars, giving them a purer air to breathe, while the comfort of the body and lower extremities will remain undisturbed. This is as it should be; for warm feet and cool heads contribute alike to physical comfort and clearness of mind. Raising the lower sash of the windows endangers the health of scholars, exposing those who sit near them to colds, catarrhs, etc. Indeed, when it is very cold or stormy, it is unsafe to ventilate by lowering the upper sash of the windows. At such times, provision should be made for the escape of impure air at the upper part of the room, and for the introduction of pure air at the lower part, as will be shown while treating upon the means of warming.

Means of Warming.—Next in importance to pure air in a school-room is the maintenance of an even temperature. This is an indispensable condition of health, comfort, and successful labor. It is one, however, that is very generally disregarded; or, perhaps I should say, one that is not often enjoyed. School-houses are generally warmed by means of stoves, some of which are in a good condition, and supplied with dry, seasoned wood. The instances, however, in which such facilities for warming exist, are comparatively few. It is much more common to see cracked and broken stoves, the doors without either hinges or latch, with rusty pipe of various sizes. Green wood, also, and that which is old and partially decayed, either drenched with rain or covered with snow during inclement weather, is much more frequently used for fuel than sound, seasoned wood, protected from the weather by a suitable wood-house. With this state of things, it is exceedingly difficult to kindle a fire, which burns poorly, at best, when built. Fires, moreover, are frequently built so late, that the house does not become comfortably warm at the time appointed for commencing school. These neglects are the fruitful source of much discomfort and disorder. The temperature is fluctuating; the room is filled with smoke a considerable part of the time, especially in stormy weather; and the school is liable to frequent interruptions, in fastening together and tying up stove-pipe, etc., etc.

This may seem a little like exaggeration. I know full well there are many noble exceptions. But in a large majority of instances some of these inconveniences exist; and the most of them coexist much more frequently than persons generally are aware of. I speak from the personal observation of several thousand schools in different states, and from reliable information in relation to the subject from various portions of the country. I have myself many times heard trustees and patrons, who have visited their school with me for the first time in several years, say, "We ought to have some dry wood to kindle with; I didn't know as it was so smoky: we must get some new pipe; really, our stove is getting dangerous," etc. And some of the boys have relieved the embarrassment of their parents by saying, "It don't smoke near so bad to-day as it does sometimes!"

The principal reason why the stoves in our school-houses are so cracked and broken, and why the pipes are so rusty and open, lies in the circumstance that green wood, or that which is partially decayed and saturated with moisture, is used for fuel, instead of good seasoned wood, protected from the inclemency of the weather by a suitable wood-house. There are at least three reasons why this is poor policy. 1. It takes double the amount of wood. A considerable portion of the otherwise sensible heat becomes latent, in the conversion of ice, snow, and moisture into steam. 2. The steam thus generated cracks the stove and rusts the pipe, so that they will not last one half as long as though dry wood from a wood-house were used. 3. It is impossible to preserve an even temperature. Sometimes it is too cold, and at other times it is too warm; and this, with such means of warming, is unavoidable. Scores of teachers have informed me that, in order to keep their fires from going out, it was necessary to have their stoves constantly full of wood, and even to lay wood upon the stove, that a portion of it might be seasoning while the rest was burning. Aside from the inconvenience of a fluctuating temperature, this is an unseemly and filthy practice, and one that generates very offensive and injurious gases.

Again: I have frequently heard the following and similar remarks: "The use of stoves in our school-houses is a great evil;" "Stoves are unhealthy in our school-houses, or in any other houses," etc. This idea being somewhat prevalent, and stoves being generally used in our school-houses, their influence upon health becomes a proper subject for consideration.

Combustion, whether in a stove or fire-place, consists in a chemical union of the oxygen gas of the atmosphere with carbon, the combustible part of the wood or coal used for fuel. Carbonic acid, the vitiating product of combustion, does not, however, ordinarily deteriorate the atmosphere of the room, but, mingling with the smoke, escapes through the stove-pipe or chimney.

The stove, in point of economy, is far superior to the open fire-place as ordinarily constructed. When the latter is used, it has been estimated that nine tenths of the heat evolved ascends the chimney, and only one tenth, or, according to Rumford and Franklin, only one fifteenth, is radiated from the front of the fire into the room. Four-fold more fuel is required to warm a room by a fire-place than when a stove is used. Oxygen is, of course, consumed in a like proportion, and hence, when the open fire-place is used, there is necessarily a four-fold greater ingress of cold air to supply combustion than where a stove is employed.