Page:Popular Science Monthly Volume 20.djvu/589

Rh hall for public speaking is, that it should bo, as to its dimensions, in harmonic proportions. By this is meant that the length, breadth, and height of the room should bear some simple, easily determinable proportions to each other; generally one corresponding with the commensurate ratio borne by the intervals between the tones of the musical scale, which is expressible by the numbers from one to six. Harmonic proportions may be represented by the combinations 6: 2: 8, 6: 5: 3, 2: 5: 3, 2: 2: 4, 2: 3:4, or others as simple. Angles, being a disturbing element, may be obviated by adopting curved surfaces, but these must not be circular, for we should then have a whispering gallery, nor elliptical, for then the sounds would be concentrated in the foci; but they should be in the shape of a parabola having its focus very near the contour. The seats should rise toward the back of the room, to correspond with the tendency of the sound to rise with the, ascending currents of air, and to prevent its being caught in the clothing of the audience. A system of ventilation should be adopted that will rather carry the sound toward the audience than in the other direction. When the amount of space for each person exceeds one hundred and ninety-five cubic feet, the walls and ceilings should be finished with resonant material; where the amount of space is less than this, the finish should present a repellent, hard, and unsympathetic surface like plaster, or like stone if the space is less than one hundred and fifty feet. The obstructions presented by the supporting-posts and the acute angular recesses of galleries may be avoided by constructing the gallery upon a system of curved iron supports beginning on the floor line against the wall and rising with a gradual parabolic curve outward, the spaces between which should be filled in with wood or plaster surface. In the light of these principles, Mr. Oakey can "see no excuse for building an apartment so that its acoustic properties shall not be as much a matter of course as keeping out the weather." Mr. Oakey also considers the sonority of party-walls, for which he suggests furring, with lathe and plaster and the removal of the bearings of floor-joists from the walls, as cheap and efficient remedies.

Heat and Health.—A sufficiency of heat is one of the most essential requisites to health; and in the administration of heat we have one of the most powerful curative agents. The sun furnishes a constant supply of beneficial warmth, of which we make much less use than we might and ought. Indeed, we too often shun that which we ought to seek, as when we deliberately and at considerable cost darken the rooms into which we ought to welcome the sunshine, or carefully exclude its life-giving rays with umbrellas and parasols. The idea of a sun cure, which was proposed by one of our physicians several years ago, was one of genuine merit, and has been strongly commended, after several years of observation in the East, by the late Mr. David Urquhart, M. P., and secretary to the British embassy at Constantinople, who has related many incidents illustrating its efficacy. Among them was that of a person who had been advised, at the baths of Gastein, to try air baths in the neighboring forests. He received considerable benefit from lying undressed in the shadiest part of the forest, but finally concluded to expose himself in the full sunshine. Although he had always supposed that the rays of the sun gave him headache and derangement of the stomach, he found that when entirely exposed he was not unpleasantly affected in any degree, but felt agreeable sensations of genial warmth. If, however, he covered any part of his body, the disagreeable feelings returned, and the covered part became intolerably hot. Occasionally a pricking and itching sensation and redness of the skin suggested the suspension of the baths for a day or two. Dr. Scanzoni, of Wurzburg, explains the freedom under these baths from the pains in the head and stomach which commonly follow exposure to the sun by the fact that the action is diffused equally all over the body, and the circulation is determined in a corresponding manner, instead of being drawn in excess to the head. Dr. Gosse, of Geneva, wrote in 1826 in high praise of the curative properties of heat, which he regarded as working by restoring the action of the skin. The hot-air bath has been used for twenty years in the Newcastle Infirmary with satisfactory results, and has been introduced into several