Science Sittings

New Zealand Tablet, 12 August 1915, Page 49

Science Sittings

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• - The-History of the Kite. - jl The 'invention of the kite is usually attributed to the Chinese. The first man on actual record as having used the kite is Archytas (about 400 8.C.). For what purpose ho employed it is not known, but it is not probable that he accomplished' anything of scientific, importance, and it- was not until 1749, when Dr. Alexander Wilson and Thomas Melville, in Scotland, used it for taking the temperature of the upper air that the kite showed possibilities of becoming a useful and scientific apparatus. Franklin's well-known experiment of obtaining atmospheric electricity by means of a kite again drew attention to it. It is, however, within the last decade that the kite has gained nearly all of its importance, and this is due to its development by men who have studied it and the forces acting upon it in a scientific way. Among others may be named Marvin, Langley, Ilargrave, and Eddy ; by their labors a hitherto useless toy has become an important scientific apparatus. , The Mora no Monoplane. The Morauo monoplane used by Lieut. Warneford has not so far been employed very much in the British air sen-ice. British airmen have generally preferred biplanes, and for a long time military airmen were forbidden to use monoplanes at all. The designer of the Morane machine was originally chief engineer to the Bleriot works, and the Morane is in many respects an improvement on the Bleriot design. It is, of course, essentially a racing machine, and has been used by most of the crack professional fliers. In recent years Garros seldom flew anything else, and towards the end of his career Gustav Hamel made all his trick-flights and one of his speed records on this type of machine. He was flying a Morane monoplane when he was lost at sea. Its merit for an attack like Wameford's lies in the rapidity with which it can climb and in its capacity for righting itself if it is turned sideways or upside down. A Wonderful Bridge. The new electrically-operated double-track swing bridge built by the Canadian Pacific Railway Company over the Lacliine Canal is a triumph for Canadian engineering and is of. particular interest to railroad builders. Unique in many respects, and among the most up-to-date in North America, this remarkable piece of mechanism is moved with the ease and apparent simplicity of the hands of a watch, although a. weight of no less than 758 tons swings upon the central pivot. The object in constructing this bridge was to complete the double-tracking between Montreal and Brigham Junction, the former bridge being the only single-track structure left between these two points. The total cost was £468,000. A Now Instrument of Destruction. At the inquest on victims of the Zeppelin raid on London, the coroner, a man of science, pointed out that ' thermit' was used for the incendiary bombs dropped by the 'invaders.' It is the trade name of a mixture of powdered aluminium and magnetic iron oxide, used in welding iron and steel and in repairing broken steel castings. When this mixture is ignited, the oxygen leaves the iron and combines violently with the aluminium, producing a slag, which rises to the surface, the molten steel sinking to the bottom. The heat evolved by the reaction is enormous, and a temperature can be attained second only to that of the electric arc. -The process was made practicable by Goldschmidt, a German, in 1898, for, although the principle was known already, serious difficulties were encountered in its application, one of them being the danger of explosion. Goldschmidt overcame the difficulty by finely dividing and intimately mixing the materials, and by starting the reaction at one point by raising its temperature sufficiently high. The thermit reaction is used largely , in the preparation of metals from their oxides, and is of particular importance in the production of chromium, ■which" is employed largely in the manufacture of highspeed tool steel and armour plate. Now it is utilised as a direct 'instrument of destruction.' . . _