SCIENCE, MECHANICAL INVENTIONS, ETC.

New Zealand Herald, Volume XL, Issue 12419, 14 November 1903, Page 4 (Supplement)

SCIENCE, MECHANICAL INVENTIONS, ETC.

STEAM TUBBINE FOR OCEAN LINERS. : ?t is persistently rumoured that the Cunard Steamship Company has under serious consideration the question of installing tur- ;: bines in place of tho customary reciprocating engines on the two great steamships which it is about to build for the Atlantic ■ service, savs the Scientific American. Our readers will remember that when the question of the construction 'of these two vessels, which will greatly exceed all existing steamships in. size, power, and speed, was finally determined upon, we expressed the conviction that the time was ripe for the "' introduction of the steam turbine into the •" Atlantic service, and that there was every .. reason whv this new type of motor should be adopted for these ships. Naturally, before venturing upon so momentous a change, the company will wish that they had for their guidance more extended records of the behaviour of the marine turbine, particularly on vessels of some intermediate size between the existing turbine channel passenger steamers and tin giant vessels which they are themselves about to build. If the Cunard Company should determine to use the turbine they will have acted with a great deal or courage and much commendable enterprise ; but. for our own part, we feel satisfied that the time is ripe for such p venture. The success of the turbine from its first installation in the little Turbinia up to the large and fast Channel steamer Queen, has been so pronounced and uninterrupted that one fails to conceive ot &nr :omnlications which might develop were the turbine employed on ocean liners, that Mould prevent the same excellent result* from being secured. Indeed, trie presumption is rather the other way, for the larger the ship the better has been the performance ; and, indeed, we have the oit- • reiterated statement of Mr. Parsons thai) the greater size of the turbines that would have to be installed in ocean liners would tend towards better result* in speed, power, end economv. A strong presumption as to the practicability of using turbine units of creat horse-power successfully on steamships is found in the fact that the units of 2000 horse-power or more that have been built for electric lighting and power plants have given such excellent service, and the electrical companies are so well satisfied with the results, that they are not hesitating to build units of as high as IU,IW maximum horse-power. Now there is no reason why the engine-room ot a- transAtlantic liner should present any obstacles •' to the successful employment of the highpowered turbine any more than it has to '* the use of the high-powered reciprocating engine. Indeed, the presumption is the other wav; for the racing of propellers, which is liable to have serious results in tne reciprocating engine, could, in the nature of things, do but little harm to the perfectly balanced parts of a large turbine.

THE EFFECT OF WIND TTPOX TRAINS.

Attention is called bv the American correspondent of Page's Magazine to a series of experiments which have been maae bj the Pacific Electric Railway Company ot Los Angeles. California, on the effectiveness of wind brakes in increasing the efficiency of its lone-distance inter-urban cars, lne tests were" attended with results of a remarkable character. Among the dmerent shaped wind brakes that were tried was one which resembled the cow-catcher of a locomotive, its base being on a level with tne floor of the car, and the knife-edge backbone extending upward at an angle of 15 decrees to the top of the car, while the sides rounded off in a convex curve till they coincided with the sides of the car. It was found that with this shield it required but 220 horse-power to make a speed of sixty miles per hour, whereas without it 290 horsepower was necessary saving of about <!A per cent, in power. Also at a speed of fifty miles per hour the result in favour ot the" hood .was 137 as again 170 horse-power. Mr. R. S. Masson, the consulting engineer of the company, under whose directions the tests were made, declares that, in the face of these hi ? hlv satisfactory results, there can be no doubt that the wind break will soon be adopted on all long-distance cars, '- THE CAKE OF OIL ENGINES. In the current number of Page's Magazine Mr. E. Kilburn Scott remarks that for countrv house lighting and the smaller isolated installations the oil engine is eminently suitable, but of all engines it is, perhaps, the one which requires most humouring. Once get it into gocd fettle, however, with the right kind of oil, the circulating water properly proportioned, etc., and an intelligent man as driver, and the oil engine is a most satisfactory prime mover. A frequent cause of trouble with the oil engine is the ■sticky piston, but this can be always traced to the use of improper lubricating oil. In one case the writer knows of the engineer had previously had experience in Stockport gas engines, and he naturally thought that the special oil sold for that engine would be suitable for oil engines. In another case no provision was made for draining the engine-bed, with the result that the crank and its balance weight splashed a quantity of ordinary mineral oil from the bearings into the open end of the cylinder—result, sticky piston and much bad language. The oils which are most suitable for oil engine cylinders are olive oil and cotton-seed oil and in connection with the latter it may be interesting to mention that its special suitability was the result of an accident at the old Trusty Engine Works at Cheltenham. Some cotton-seed oil had been ordered for another purpose, and it was used forgone engine quite accidentally. At first sight the oil looks as if it would be most un-

suitable for such a purpose. To everyone's surprise it proved a complete cure to the sticky piston troubles, which until then •had been the most serious difficulty the company had to contend with. As the heat from the cylinders assists in keeping up the temperature of the ignition tube, it is important that at low loads there should not be too much circulating water, otherwise the cylinder may get too cool. Below quarter-load, in fact," it is frequently necessary to apply a lamp or some external heat to the ignition. It has occurred to the writer that this could be dispensed with by throttling the circulating water as the- number of explosions become reduced. Another way would possibly be to bafflle the water from circulating round the firing end of the cylinder. EASY WAT. OF MEASURING HEIGHTS. Anyone who knows how to take the altitude of the sun or a star with a sextant, and wishes to take that of any distant hill, steeple, or the like, should put a tea-tray on the ground, and fill it with water, and then retire from it until the top of the hill, steeple, or what not, is reflected in the liquid. Now take the sextant, and make the image of the summit coincide with its reflection in the liquid. The angle of elevation will thus, obviously, have been measured double. Half of this will give the measurement required. AN* IDEAL MATERIAL FOR YACHTS. The hulls of large racing yachts present many problems other than the general design and the lines. The question of material is one which constantly troubles the marine architect. It is now reported that "selium" seems to have certain properties rendering it invaluable for airship and yacht construction. The new metal is lighter and stronger than aluminium and costs one onetwelfth as much. It does not rust and takes a fine polish like nickel. Should it be found not to pit under the influence of sea-water and no electrolytic action sets in, it will be an ideal material for the yachtbuilder. FUEL FP.OM CABBAGE.

Attempts to derive illuminating gas from sewage were made many years ago with but qualified success. Nor can it fairly be said that dust destructors for burning up the refuse of towns by a sort of forced selfcombustion have always been entirely satisfactory. A patent which has been taken out by Mr. Eugene C. May in Chicago describes a fresh process for deriving fuel from garbage. The garbage, after being first cleared of metal and glass pieces, or any other undesirable substances, is run through a crusher, which breads up the brittle portions and reduces the softer substances to pulp. About three per cent, of calcium chloride is added to disinfect the mass, and it is then dried by evaporation. Aoout 4001b of crude oil is now treated with 1001b of potassium protaxid, which causes the oil to coagulate and form a soapy substance. The oil is then thoroughly mixed with a ton cf the dry garbage, and, with three per cent of coal £3 ft binding agent, is moulded irite briquette* ready for use. It gives r, clear, dry. flame, and is. entirely free from offensive odours.