PROTECTION FROM HEAT

New Zealand Herald, Volume LXXI, Issue 21769, 7 April 1934, Page 7 (Supplement)

PROTECTION FROM HEAT

USE OF ALUMINIUM FOIL London policemen, troops in Fgvpt, huts in the desert, and laboratory experiments in England have all been responsible for the discovery that aluminium foil can be used as a most effective protection against extremes of external temperature. It is a well-known fact that bright metallic surfaces radiate very little heat compared with black matt surfaces at tho same temperature. They also reflect much of the heat they receive. Air is also a. poor conductor of heat, and the. principle employed has been the use of an insulator consisting of material covered on both sides with aluminium foil, fixed so as to divide the air space across which the transference of heat is to lie hindered.

In one series of experiments water was kept boiling by an electric bulb, and four panels surrounding the vessel were tested for the temperature reached. Asbestos, cork, as well as the aluminium foil insulator, were used, and, after two and a half hours, there was only a rise of 16 deg. F. above room temperature for a panel of asbestos and aluminium foil as compared with a rise of over 54 deg. F. for two sheets of asbestos cement.

Used for huts in the desert, Dr. G. P. Crouden, who is responsible for these investigations, found that a lining of three-ply wood with a rein forced aluminium foil insulator between tho wood and the external corrugated iron, the rise in temperature in the hut was less than half of the rise in another hut with a three-ply wood lining only. Ou board ship, l)r. Crouden was able to show that aluminium foil can be used to cut off the heat of funnels or of boilers in the stokehold to a considerable degree, and similar protection from heat can be obtained in tents, trains, and ambulances. Experiments with tropical helmets have shown that it is possible to stick aluminium foil as a lining to the helmet and thus reduce the amount of heat radiated to the head to one-twelfth or one-tenth of what it was before. London police helmets can also be treated in this way, and further work has also been carried out in the protection of food from the influence of heat. At shade temperatures in the tropics ice melts only half as fast if aluminium lining is used for containers.

GIANT TELESCOPE A telescope weighing 1,000,00011 i. that is being built for the California Institute of Technology, is expected bv astronomers to solve the problem of the alleged expanding universe. Dr. Hubble, astronomer at Wilson Observatorv, said recently that he was confident the new instrument would answer this question that had been perplexing astronomers for some time past. Experts at this great observatory had been looking for the answer, he said, in objects so far away that it takes 300,000,000 years for their light to reach the earth. The new telescope will penetrate distances three times as far, and unfold a volume of the mysteries of space 25 times as vast as that possible with the world's present greatest telescope with its lOOin. mirror. ELECTRICITY IN THE SKIN Electrical currents generated in the skin by emotion and disease are being measured by a new metre that was designed to aid in diagnosing human ills. The device registers the currents in different parts of the body at the same time, showing them to be different, as though the body were a house with the light in one room turned on brightly and the light in another very dim, or perhaps turned off. Dual personality is detected by the metre by a marked split in electrical conditions between the right and left sides of the body. The typical normal person shows slightly higher electrical resistance and higher electrical reaction on the left side. Differences are found between the electrical conditions of the palms and the backs of the hands. Warm weather, nervous conditions and strong or prolonged stimulation show up in the palms in the form of extra moisture ans electrical changes.