VENTILATION

EVERY apartment of a school-house should be provided with a cheap, simple, and efficient mode of ventilation, by which the air, which is constantly becoming vitiated by respiration, combustion, or other causes, may he constantly flowing out of the room, and its place filled by an adequate supply of fresh air drawn from a pure source, and admitted into the room at the right temperature, of the requisite degree of moisture, and without any perceptible current. These objects may be attained by attention to the following particulars:

1. The location of the school-house must be healthy, and all causes— such as defective drains, stagnant water, decaying animal or vegetable substances, and manufactures, whose operations evolve offensive and deleterious gases-calculated to vitiate the external atmosphere, from which the air of the school-room is supplied, must be removed or obviated. 2. The means provided for ventilation must be sufficient to secure the object, independent of doors and windows, and other lateral openings, which are intended primarily for the admission of light, passage to and from the apartment, and similar purposes. Any dependence on the opening of doors and windows, except in summer, will subject the occupants of the room near such points to currents of cold air when the pores of the skin are open, and when such extreme and rapid changes of temperature are particularly disagreeable and dangerous.

3. Any openings in the ceiling for the discharge of vitiated air into the attic, and hence to the exterior of the building, or by flues carried up in the wall, no matter how constructed or where placed, can not be depended on for purposes of ventilation, unless systematic arrangements are adopted to effect, in concert with such openings, the introduction and diffusion of a constant and abundant supply of pure air, in the right condition as to temperature and moisture.

4. All stoves, or other heating apparatus, standing in the apartment to be warmed, and heating only the atmosphere of that apartment, which is constantly becoming more and more vitiated by respiration and other causes, are radically defective, and should be altogether, without delay, and forever discarded.

5. Any apparatus for warming pure air, before it is introduced into the school-room, in which the heating surface becomes red-hot, or the air is warmed above the temperature of boiling water, is inconsistent with good ventilation.

6. To effect the combined objects of warming and ventilation, a large quantity of moderately heated air should be introduced in such a manner as to reach every portion of the room, and be passed off by appro