Science Siftings

New Zealand Tablet, Volume LII, Issue 11, 25 March 1925, Page 62

Science Siftings

By "Volt"

World's Strongest Wire. Twenty-five thousand miles of wire, the strongest of its kind ever made, will be used in the two cables supporting the world's longest suspension bridge now being erected across the Delaware River at Philadelphia. The wire, long enough to girdle the earth, is shown by tests to have a stretching strength of 223,0001 b per square inch. After assembly into the cables it will hold against a pull of 36,000,0001 b. The total length of the Delaware River bridge, including plazas, is 9760 feet. The First Tramway. It is recorded that the ninth Duke of Norfolk laid a tramway with wooden rails in 1774, with a view to assisting and cheapening the transport of coal. The local people did not appreciate the innovation, and serious riots occurred, in the course of which the lines were damaged. They were afterwards replaced by iron rails, and it is contended that this was the first tramway in the country to be so constructed. James Outram's cast-iron track plates laid on wooden cross sleepers, which were afterwards replaced by cast-iron boxes and then by stone blocks, were "Outram ways," but it seems probable that the similarity between this term and "tramways" is only a coincidence. The One-man Tram. A new type of tramcar is to be put into service in London. It is controlled entirely by one man, who combines the jobs of driver and conductor. To make this one-man control possible, a number of ingenious mechanical devices are used. .The car holds thirty passengers, who pay their fares as they enter, dropping the coins into a fare-box. The driver issues the tickets, which are cancelled by a foot-operat-ed punch. A machine which gives change is another feature. "Safety first" is the motto in a number of other interesting devices. For instance, the air-brake handle is fitted with a "dead man grip," and the doors cannot be opened while the car is in motion. How Camphor is Made. As a perfume, camphor has been known and valued by the people of China and Japan for centuries. Originally obtained from gum deposits occasionally found in old camphor trees, it is now extracted from the wood itself, which after being sawn through lengthwise, is reduced to chips and heated in a still. The-vapor given off in this way passes through bamboo pipes into a cooling chamber, where it condenses in crystal form, known as "flowers." These 'crystals are collected ! and exported to Europe, where they are further purified by being mixed with lime and charcoal and refined in special retorts. ; The "oil thus obtained should not be confused with camphorated oil, ! which, consists of camphor dissolved in olive oil! -' ']

Voice From a Fan. fThe latest gramophone has no horn, no tonearm, and no sound-box. In place of these there is a pleated upright diaphragm fourteen inches in diameter. At the bottom of this fan is a needle-holder, very like the ordinary one, into which the needle is fitted and set going on the record in the usual way. This simple apparatus is said to reproduce a voice so well that if the gramophone is placed behind a screen it is impossible to say whether a human being is there or a machine. The inventor is a Frenchman, M. Lumiere, who was making investigations into acoustics when he was surprised to hear a strange noise coming from the centre of a fan of pleated paper with which he was experimenting. A River That Gets Rusty. Can you imagine a river that gets rusty? There is one which is subject to this phenomenon—the River Ob, which falls into the Arctic Ocean and runs through the north of Siberia. . . The Ob contains a great amount of iron. Every year when it freezes over the iron is cut off from the air. The result is that the mental precipitates, or in other words, instead of being dissolved in the water, becomes a solid. The whole underside of the ice i? covered thickly with rust, and even the fish and other creatures become rusty. In the lower reaches, where ice does not form, the water, ordinarily quite clear, becomes cloudyand discolored. The whole river, 2300 miles long, becomes poisonous.. People living near it have to quench their thirst with melted snow, and most of the fish leave the river and seek safety in.the sea. They are told by instinct whe.i the timo arrives for their annual exodus In the spring the ice thaws and.the air renders the river free from poison. . The fish immediately return. They, swim up the stream in such vast .lumbers that they are packed tightly together. Any boao that tries to navigate the river at this time fo c«s thousands of fish* on to the flat banks, where the natives kill them with sticks.