Science Siftings

New Zealand Tablet, Volume LII, Issue 7, 18 February 1925, Page 62

Science Siftings

By “Volt"

Icebergs Ahead! ; The menace to navigation from floating icebergs is well known. Only one-tenth of the mass of a floating berg is visible, the other nine-tenths being submerged. As melting proceeds, the centre of gravity shifts; and a berg that looks as solid as Gibraltar is apt to tip over suddenly, with disastrous results to a ship which may have been at an apparently safe distance. Likewise, the immersed part is of such indeterminate extent that a ship may ground on it while the pilot is under the impression that he is still in safe water. In order to .avoid these dangers it is necessary that the approach of the iceberg be known before it becomes visible. A “radiomicrometer” has been made for iceberg detection. The instrument consists of two parts thermocouple ' and a spherical mirror. The thermocouple is enclosed in a vacuum tube from which the air has been exhausted. The mirror has a silvered front so that the radiation has not to go through the glass, which would absorb part of it. There is a temptation’ to describe the work of this radio-micrometer in the locality of icebergs as depending upon the “radiation of cold” by the berg, but the berg, being at a temperature some'- hundreds of degrees above absolute zero, is in fact radiating heat, but heat of low intensity. The thermocouple reacts to this heat, and as it approaches the berg it gives a galvanometer reading in accordance with this fact. Tanks for Divers. Modern salvage enterprises demand greater and greater, ranges in deep-sea . diving, and as the depth to which a diver, can descend is limited by the pressure of water his body can sustain without risk of .collapse, improved forms of diving suits and accessories are being continually devised. Few of these, however, increase the diver’s range of operations by more than a few fathoms, and the maximum depth to which even the most expert, diver can go remains at about 200 feet. Actually men have gone to as great a depth as 300 feet, but under such conditions no work could be attempted. Moreover, the men who made this record were permanently incapacitated as a result, A new apparatus has little in common with the usual type of diver’s outfit. It resembles a small U-boat turret, ' which by means of a double telephone can be kept in constant communication with the surface, and which is provided with movable arms and legs to accommodate the limbs of the diver. The arms and legs are surrounded by sleeves made of a tough aluminium alloy.’ Such a diving tank enables the diver to descend or rise .at. will, by admitting or discharging water, replacing it with compressed air from a battery of six cylinders. One diver descended 530 feet in the course of tests, though at this depth the pressure amounted to 2251 b per square inch.

Harnessing the Wind: Coming Revolution - in Industry. f Herr Flettner, whose revolutionary tion in aerodynamics has created world-wide interest, believes his discovery will affect all branches of technical industry. Expectation in Germany has been raised to a high pitch by reports of Auton Flettner’s revolutionary inventions in aerodynamics (says the Berlin correspondent of the Daily Chronicle). But for the .success of his three-rudder, people would be inclined to take him for a kind of aeraqueous “Jules Verne.” It is said that the patent rights for Great Britain in the Fleetner rudder have been purchased for a large sum by an English concern. Hamburg Line’s Action. German newspapers state that the Hamburg Amerika line intends to introduce Flettner’s rotor-turrets on a number of its big freighters. Flettner, himself in an interview in the Tagehlatt, states that even the largest ocean-going steamers can employ the rotor-turrets and so save as much as 90 per cent, of fuel. This economy would mean a reduction of freight and passenger rates “by at least two-thirds.” The statement says; “By means of rotorturrets mankind will for the first time be able to exploit the millions of horse-power contained in the winds and hitherto squandered by nature,” says the inventor. The cost of building rotor-turret ships would be po higher than in the case of others. Only 2 per cent, of artificially produced power is necessary to start the machine the rest is got from the wind. “It will be possible,” Herr Flettner maintains, “in the case of big ocean steamers fitted with proper apparatus to get 10.000 to 20,000 h.p. from wind force alone.” Herr Flettner believes that electricity works, for instance, driven by the wind can be built to supply all electric energy needed. Some of the industrial concerns in Germany are supporting Flettner’s projects. Within six months Berlin is to have an aerodynamic transformer in the shape of a rototower 330 feet high, chiefly for further experiment. By the use of such towers the price of electricity will be much reduced in the near future, the inventor told the interviewer. Some of these days, sailormen will be doing the Australian idea of the im-possible-harnessing a “southerly buster.”'