SCIENCE SIFTINGS.

Auckland Star, Volume XLVII, Issue 156, 1 July 1916, Page 14

SCIENCE SIFTINGS.

•MAKING MIRRORS WITH HYDROGEN. Metal-backed mirrors can, it is claimed, be produced in thirty seconds by what is stated to be a new process of electro deposition. A gUuss plate for the mirror in juxtaposition to a sheet of metal to be used as backing, is enclosed in a glass bell resting on a ground-glass plate When, after the bell has been exhausted 01 air, hydrogen is passed through the boll simultaneously with an electric current, the metal is disintegrated and deposited in a thin film on the glass plate, producing an opaqne mirror. Gold, silver, platinum, copper, nickel, iron, palladium, or irridinm can be used as the metal backing—"Science Sittings." MAN WHO CAN INCREASE HIS OWN HEIGHT. Dr. Zethden Tccently showed before the medical society a. performer in a Berlin circus who is able to increase the length of his body by nearly Sins. By three years' training he had developed his muscles co that he could stretch the intervertebral (between the spinal bones) discs and the ligaments and tendons. The stretching was especially visible on the neck and back, where the muscles had become marvellously hypertrophied. He has been able to maintain the stretching for eigiht hours. The man hae the respectable length of about sft 10in, which after stretching is increased to about 6ft funs. He has never, eaye the Berlin correspondent of the "Lancet," used a special diet. SMOKING HURTS ARTERIES. Dr. H. John, of Dortmund, Germany, hae been making a special study of the influence of tobacco smoking on the circulation of the blood. The journal of the American Medical Association eums up this conclusions by saying his measurements indicate that the smoking of two "medium" cigars causes characteristic alterations in arterial pressure. These experiments confirm the widely current impression that nicotine can produce changes in the ooate of the arteries. Therefore anyone with a tendency to hardening of tile arteries ought to be extremely moderate iv hie nee of tobacco. PREVALENCE OF NASAL CATAKRH. Dr. W. Ereudenthal, a foreign phyei ciau, states thai in order to lessen tha great prevalence of catarrh, prevailing systems of heating, where closed etoves or radiators are employed, should be changed co as to allow much more moisture to evaporate in each living room. This ie specially important in echoole or meeting halls of every kind. A pail of water in front of the heater is ineffective. One should employ other means in order to overcome the deficient humidity indoore. In order to prevent coUte excessive clothing should not be worn. Young people should be hardened to exposure to draughts, rain snow, and other inclemencies of the weather, INSECTS IN THE UPPER AIR. Dr. E. Evorling, of Germany, is trying to interest aeronauts in making observations of tho occurrence of insects at attitudes of several thousand feet above the earth's surface. Very few such observations have .heretofore been recorded. Dr. Everting himself, in the course of many balloon voyages, has only once noted an insect (a butterfly) at a great altitude. It was, in ail probability, carried thither by the strong uprush of air in an incipient thunderstorm, and it may be a general rule that insects do not voluntarily rje* above a moderate elevation.