SCIENCE AND INVENTIONS.

New Zealand Herald, Volume LII, Issue 15948, 19 June 1915, Page 4 (Supplement)

SCIENCE AND INVENTIONS.

THE WORLD'S 'STRONGEST CABLE. All records 'for cable etrongth are said to have been surpassed when a 3in steel cable •withstood a pulling '..teat .of? 751,0001b, or practically 376 tons. This cable ig.,to form part of the longest^'and* strongest hoisting'cable in the world, and is, to be used in a mine in Cuba. It weighs 15,71b to the foot, 'and 'is made in • lengths', of 8000 ft. \ This cablo lias.ft hemp centre, around which are wound six strands consisting "of : 19 steel wires each. . SLEEPING CAR VENTILATION. The lower ' berth in a sleeping car is stuffy "with!, the windows closed and ' if you open the window th«, cold air;' is directly on you. It is thought that the riding- public" would appreciate some 'deflector or diffusing construction which could lie applied to the> open windowover the' usual short hinged screen ■ and permit the entry of fresh' air, at; the same time preventing it from blowing directly on'the passenger in the berth. ,

-MAKING AEROPLANE WINGS. _ Various kinds ,of -material, Including linen, silk, cotton, celluloid films, and aluminium foil, have been tried for, covering 'the wings of aeroplanes, but none has proved 'so '(satisfactory so far as linen covered 'with several coats .of' a rubber solution. This coating increases the strength of the linen aboutj'6,- per. cent., makes it more enduring "under, varying weather conditions, and causes it to stretch to an absolutely smooth surface, a feature that is of .tho utmost. advantage . in* fast' flights. Silk, which would seem to make an ideal covering on account of its lightness and strength, has been found unsatisfactory, as .it does' not , Withstand exposure to sun and rain', J and does not lend itself'readily to the application 'of coating compounds. '

■ WIRELESS LIGHTHOUSES. . Trinity House is .following very closely an v experiment ,in the uso of ' Hertzian waves, and it is believed ,that ; the system will "prove of far more lasting; value than coast lights, since it .can, be successfully employed in foggy .weather when: the lighthouses- cannot be seen. Several steamers are now. fitted' with what are' known as direction-finders.. 'When-near a...wireless station on shore,;the navigating. officer of a ship can, with the assistance of one of these instruments, , take bearings under the worst ; of weather conditions and thus 1 lessen risk of collision. Some experts, in facfcJ-Jook forward to the gradual extinction of coast lights. On the north coast of France the French Government has for some time been experimenting with Special stations for the purpose, the signals being emitfed at regular intervals.

NEW TELEPHONE RECEIVER. The latest thing in telephone receivers is onq thai "is no larger than half an inch of lead-pencil .and is designed to be placed in the car' instead-, of being held against it. The electromagnet and diaphragm of the ordinary l receiver are eliminated and are replaced by a very . fine platinum wire housed within a small cover which is pierced by a minute opening., As the currents pass through the wire they cause small increases and decreases of heat, and the resulting expansions , and contractions of the surrounding air are transformed into sound. The sounds produced by this receiver: are not so load,; as those produced by the receiver, but have the advantage of being pure in : tone and are sufficiently loud) for all practical purpose# when the receiver is placed,in the ear. y , r , . - • V ■. • • - > v. -. ■ \ A SECTIONAL INNER- TUBE. .J ; In an endeavour to . solve ■' the puncture problem, a New York inventor has brought - out ja sectional . pneumatic tube— an idea ; which has. occurred to more jthan cue inventor- ' The tube consists /of fifteen sections, each in itself«» complete'/iiner tube, not unlike a string of •■''sausages. Each section is connected with" the ; main valve', by a metal tube. witßiil the rim. When a • puncture ' occurs,' the apace formerly occupied by] the punctured: section is at ? once . taken' up ,by the two adjoining sections, ; which : expand and ' maini tain the,air• pressure in the : tyre. Tyre j experts who have examined • the tubei are i of • the] impression that if two adjoining sections * should ' be ) punctured ; before the tyre; is renewed, 1 the side pressure from the adjoining sections, in trying !to fill up' the racant' space, would' be so strong as to t«ar out the valves of these sections.

■>' SUBSTITUTE FOR T WOOD. A composition that has many advantages over wood for making small patterns can be ' made as . follows ".—With hot water mix into a thick paste three parts by volume of starch, one part ground glue, two . parts fine, resinous sawdust.- The sawdust should not be added until the starch and glue have been dissolved by the water. After the ingredients are thoroughly mixed, heat tlie whole to 190deg. Fahr. and continue the heating until the whole becomes a hard mass, then allow to cool and remove from the receptacle. The resulting: composition is .a a strong, hard, ■ horn-like .1 substance that can be machined, sandpapered, and varnished the same-as wood.* The principal advantages .of this, composition over wood' lie in ; the fact" that it' has. no grain,' and therefore turned - and - complicated patterns made from it do not have to be built\up or glued together, , and that for the same reason it is ' easier. to ' turn and machine; and offers a smoother surface when, finished. 'It is also more fireproof than wood and not .so readily affected by atmospheric changes. ■ ••-. t, ,'. * ' PETROL IN' AUSTRIA. Doubts have been' cast upon the statements, made some, time ago as to the inconvenience causod in Germany and Aus-tria-Hungary . by a shortage, of .' petrol for motor-cars. Thlit the inconvenience is real, not to say serious, is borne out by the observations of ■> a special correspondent of the ■ Morning Post, who has contributed to' that journal a series of articles on the present condition of Austria-Hun-gary. In his communication from Buda Pesth, he says : —" What immediately struck mo in Buda Pesth was that there wero absolutely no motor vehicles. • Some, I was told, had been commandeered by the War Office, hut the real reason for their complete absence was the lack of petroleum. . . Petroleum has now risen bo much in price a 3 to be beyond the reach of almost everyone, and this despite Buda Pesth being .nearer to petroleum springs and refining works than any other town in Europe." THE ORIGIN OF KHAKI. Khaki, the dun-coloured maferial now so widely used for military uniforms, was discovered by an accident. For many years the British troops in India wore a cotton cloth of a greenish-brown, but it always faded when washed with soap. Whilo talking over this defect with some British officers, a business man from England said that a fortune awaited the manufacturer of a cotton drill that would not fade. One of the officers, a young man, took the hint. .. When he got home he employed a skilful dyer, and the two began a systematic search for an olive dye that, when used on cotton cloth, would not yield to soap or soda. They spent years in experiments, but without'success, and had almost began to give up hope. One day, however,, they found among numerous scraps of dyed cloths one that retained its colour under the most severest tests. The puzzling part of it was that this scrap had been taken from a piece of cloth which had gone through the same processes, but which had failed when tested. For a long time the experimenters tried to solve this riddle. The one bit of cloth mentioned was the only piece that kept its colour against all attacks. Finally, by the merest chance, they hit upon the secret. The dye, in which this scrap had been dipped had remained for a time in a metal dish of a : peculiar kind. This metal, in combination with the chemicals of the dye. had furnished the very thing needed. They made the experiment with other pieces, the dye hey, and (heir [fortunes' were made.