Science Siftings

New Zealand Tablet, 4 June 1914, Page 49

Science Siftings

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Another Channel Tunnel. * , The project for connecting Great Britain and Ireland by means of a tunnel is being revived. Mr. H. G. Tyrrell, of Chicago, engineer, suggests that a tube carrying a double railway track could be constructed between Black Head and Port Patrick for five or six million pounds. The weight of the tube, according to Mr. Tyrrell’s calculations, would be such as to make it slightly buoyant when empty. This buoyancy would be resisted by anchor chains. Any downward pressure set up by the weight of a train, within the tube would be resisted by floats. The tracks in the submerged tube would lie about 60ft below the surface. The tube would be built on shore in convenient lengths of 200 ft to 400 ft, with closed ends and then towed out into position and sunk. Air Brakes for Aeroplanes. A highly ingenious device is about to be embodied in a new British aeroplane now nearing completion. A difficult problem, which has always confronted the aeroplane designers, has been that of enabling machines to land at a reasonably slow speed and yet fly as fast as possible. The necessity of this provision may be gauged from the fact that the modern aeroplane, with its full load, weighs the better part of a ton, and that" the usual flying speeds range from sixty to eighty miles* an hour. A well-known designer has adopted the expedient of providing his latest- biplane with what may be termed ‘ air brakes.’ These consist of flaps hinged to the rear of the planes, capable of being turned at right angles to the direction of flight, with the object of enabling the pilot to reduce his speed materially preparatory to alighting. Soap Mines. Soap mines exist in several districts in North America. There is one in Nevada, on the line of the Central Pacific Railroad. This natural soap; which lathers with ease, is embedded as compactly as new clay, and the soap mine is of considerable extent. A soap mine exists at Ashcroft, in British Columbia, forming the bottom and sides of a lake which contains water strongly impregnated with borax and soda. These having solidified, the substance can be sawn out in blocks v as if it were ice. Another natural soap mine or well was discovered in Dakota, U.S.A. The soap is skimmed from a boiling spring, and hardens by exposure to the air. It is like soft clay, and can be gathered with a shovel. There are soap banks or mines on Owen’s Lake, in California, which for several years have been extensively used. Why the Stars Twinkle. Perhaps you remember that in youth some kindly elder soul took you into the darkness of some glorious summer night and pointed out the stars and planets,telling you glibly enough that the unwinking star overhead was a planet, while ‘ that blue one down there which twinkles ’ was a star. The fact that planets shone only or mainly with reflected light, while the stars ‘ burned,’, was supposed to explain the twinkling, as against the steadfast radiance. Even this young illusion is dispelled by a British scientist, who says: ‘ The twinkling of the stars is chiefly an effect produced in our atmosphere upon the waves of light. It is due to currents and strata of air of different densities intermingling and floating past each other, through which the light passes to the eye. It is seen much more in cold than in warm weather, and near the horizon more than overhead. The same effect may be seen by looking out of a window over a hot radiator, or at-a candle held on the other side of a hot stove, so that one must look through a body of highly Leafed air at the candle flame. The flame will be seen to wave and quiver. The various layers of air are at different densities and in motion. Rapid twinkling of the stars is a sign of a change in weather.’ , , <