SCIENCE SIFTINGS

New Zealand Tablet, 21 April 1921, Page 46

SCIENCE SIFTINGS

(By "Volt.")

■ .) Rocks that Bend. '•;•$ There are. rocks that .will actually bend if placed ~ in certain positions. v Some sandstones will bend like . pieces of indiarubber. If a moderately thin piece of ' sandstone is supported only at its two ends, it will sag in the middle; while if a piece is supported in the middle, the two ends will drop. Flexible rock is found in India, and also in America more especially in Brazil. It contains a proportion of mica, which is largely used for making lamp chimneys on account of its flexibility. The presence of mica does not, jjj however, account for the bending quality of the rock, ,■ which is due to the fact that the particles of quartz of which it is composed are interlocked together like hinges, with spaces in between the particles, in such a manner that though the rock will give to a certain extent it will not break. Smokeless Steamers and Trains. " ; A great. deal of interest is being taken in the oilfired ship and express train, but there is a, good deal of misconception as to the way in which the oil is used. It is not used in the ordinary manner in which a paraffin lamp is lighted, nor is the oil itself anything like that in color or constituency, The great liners, Aquitaiii., and Olympic, which are using this new fuel for the Transatlantic passage, use an oil which is a heavy black liquid, something like black treacle, stored generally in double-bottomed tanks at the bottom of the ship. It is pumped by powerful lifting pumps, heated through special heating devices, and strained. . " < It is then pumped through special burners fitted in the front of the furnaces at a pressure from 60 to 150 pounds per square inch, and mixed during its ejection from a fine nozzle point to secure a spray with a proportion of air. \ Naturally, the pressure of the oil varies with the f type of apparatus, and by the adjustment of the quantities of air and oil so can the presence or absence of 'smoke be obtained. .When all oil is burned a thick, dense smoke screen can be obtained to camouflage the vessel or train, but when the correct proportions of . air and oil are being used there is an entire absence of smoke. Different systems are used for steamers and trains. In the first case the'conditions in the stokehold are made more pleasant for the men, the arduous work of shovelling is entirely eliminated, and the number of men is reduced by 20 per cent, at the least. The work of the men consists of occasionally observing the flame of the furnace through a glass panel, and of regulating . the valves supplying the air and oil. In the case of a railway train the number of at- : tendants on the footplate is not reduced, but the work of stoking is eliminated, and with the Scarab system of firing, which is used by the London and NorthWestern way. Company, 30 pounds of-oil per mile v do the same work as 70 pounds of coal'. y This type, of oil apparatus was invented by Colonel \l F. R. Macdonald whilst he was on war service in Mesopotamia, and a locomotive can be converted to. this a system in four days. It is extremely simple and, by ? an ingenious device, a jet of steam vaporises the oil, . <j so that it burns-entirelv without smoke. •:. ,:■;..,; ' With this fuel of the future there is every possi- > i bility of even electric traction on land being r] super- /, 7. seded, and already a number !of .works, and factories j are-using this method : of -firing. \ This is notably the 7,1 case in chemical works, where a very intense heat is not so necessary as in iron and steel foundries, whilst j for s the ordinary manufacturer this fuel holds out I tremendous possibilities. The day' of the , coal-driven 7J steamer and /train/ is passing, u and already the new l'77j designation, "motor-ship,'\H is f- appearing in official I registers. .7';,,7-;i7«' v r' 7k' '■'■ .Or--- «r <ty iiiM^bv^-'-ivl^^^vp^J