Page:Popular Science Monthly Volume 28.djvu/582

566 by affixing to one side of the tub a perforated shower-tube connected with the hot and cold water supplies. The bather sits upon a chair at the foot of the tub, enveloped in a curtain of rubber cloth, with an attachment extending over the tub. He is thus assured the full benefit of all the evaporation from the hot water, while his face is totally shut off from it, so that he does not breathe any of it. By means of another equally simple attachment, substances with which it may be desired to medicate the bath are brought into contact with the water and made to mingle their fumes with the steam. This form of bath, which has all the advantages of the Russian bath, and is, moreover, adapted to domestic use, has been introduced into a great many houses in New York and other places, as well as into hotels and public institutions, and is highly recommended by those who have employed it or examined it. In another form of apparatus, sold by J. Allen & Pons, of London, the lamp is placed outside of the curtain, within which the vapor is conducted by a pipe. The whole apparatus can be packed into a box less than twelve inches square. An arrangement is also furnished by which the vapors are introduced into the bed in which a patient may be lying; or the lamp, if preferred, may be put directly under the chair. This bath has received medals and high awards at several "health" or "sanitary" exhibitions.

A Sun-heating Apparatus for Rooms.—Professor Edward S. Morse, of Salem, Massachusetts, has tried the experiment of calling in the heat of the sun to assist in warming and ventilating his house. He attaches to the wall of his house a box nearly the height of the story, about three feet wide, and of suitable depth, and so arranged and connected with openings in the wall as to act as a flue. The outside of the box is made of slate or black corrugated iron, substances which absorb boat, and over this is a "window" of glass. With this apparatus, the air in a room measuring twenty-one by thirteen by nine feet, could be changed in forty-five or fifty minutes, and a very perceptible degree of warmth was obtained. A similar heater, forty-two feet long and six and a half feet wide, attached to the Boston Athenæum, is estimated to do work that would ordinarily require between twenty five and fifty pounds of coal a day.

Earthquake-proof Buildings.—The committee of the British Association appointed to investigate the earthquake phenomena of Japan, after reporting upon their experiments into the nature of the vibrations of the ground, offer some suggestions on the construction of earthquake-proof houses. In a house resting at its foundations on cast-iron balls, the measuring instrument showed that, although considerable movement took place at the time of an earthquake, all sudden motion had been destroyed; but wind and other causes produced movements of a far more serious character than the earthquake. To give greater steadiness to the house, eight-inch balls were tried, and then one-inch balls. Finally the house was rested, at each of its piers, upon a handful of cast-iron shot, each one fourth of an inch in diameter. By this means the building has been made astatic, and, in consequence of the greater increase in rolling-friction, sufficiently stable to resist all effects like those of wind. The shot rest between flat iron plates. When erecting a building in a region subject to earthquakes, it appears that we ought first to reduce, as far as possible, the quantity of motion which ordinary buildings receive; and, second, to construct a building so that it will resist that portion of the momentum which we are unable to keep out. To reduce the momentum we may—1. Select a site where experiment shows that the motion is relatively small. 2. For heavy buildings, adopt deep foundations (perhaps with lateral freedom), or, at least, let the building be founded on the hardest and most solid ground. 3. For light buildings, put in the shot foundations. As against the momentum which can not be cut off from the building, it should be borne in mind that it is chiefly stresses and strains which are applied horizontally to a building that have to be encountered. A vertical line of openings, as in doors and windows in a building, constitutes a vertical line of weakness to horizontally applied forces. Avoid coupling together two portions of a building which have two vibrational periods, or which, from their position, are not