Science Siftings

New Zealand Tablet, 21 August 1913, Page 49

Science Siftings

By ' Volt.’

The Cultivation of Sponges. The color of the living sponge is black, becoming brownish at the base. The plan of the sponge culturist is to grow sponges in quantities large enough to be of commercial value, and that this may be done economically they must bo grown in water, shallow enough to leave them easily accessible, without the aid of diving apparatus, which is expensive to maintain. The Aluminium Industry, ■ Although the early expectations of the wholesale substitution of aluminium for steel and iron have not, for very good reasons, materialised, it has shown such a perfect adaptability to certain of the arts that the demand for the new alloy has grown enormously. From a production in the United States of less..than 100,0001 b in 1883, in 1893 the output had grown to 350,0001 b, in 1903 to 7,500,0001 b, and to-day it is in excess of 50,000,0001 b. To Test Wallpaper. Many of the cheap papers contain arsenic, and this poison is most dangerous to human beings. The following is a test which is easily applied: Take a piece of . the paper, and dip it into a saucer containing strong spirits of ammonia. If arsenic is present the green paper will gradually turn blue in color. If the color only changes slightly a little crystal of nitrate of sliver (caustic) added to the ammonia in the saucer will cause a yellow sediment, (showing that arsenic is present. \ A Jet of Water. A factory in Grenoble, France, utilises the water of a reservoir situated in the mountains at a height of 200 yards. The water reaches the factory through a vertical tube of the same length, with a diameter of considerably less than an inch, the jet being used to move a turbine. Experiments have showed that the strongest men cannot cut the jet with the best tempered ■ sword; and in some instances the blade has been broken into fragments without deflecting a drop of water, and with as much violence as a pane of glass may be shattered by a blow from an iron bar. It has been calculated that a jet of water a small fraction of an inch in thickness, moving with sufficient velocity, could not be cut by a rifle bullet. Ships of Concrete. t» A 500-ton concrete scow was recently launched at Baltimore Maryland. It is 110 ft long, 28ft wide, and has a depth of 10ft 6m. Others, built before this one, have shown a large saving in repairs over wooden craft. it is claimed by the builders that concrete vessels will ultimately create a revolution in ship construction. The Italians have already made use of concrete vessels, and have found them practicable, it is stated. Indeed, they seem to be of. exceptionally stout build, for one of them, rammed by a small war cruiser, showed no other injury but a crack, which it was quite possible to repair success y. This accidental test gave the constructor much satisfaction. The Making of Films. The immense amount of work entailed upon the German censorship of films is almost incredible. AciS d nnn ■ to j h0 £ 2? Cial «ms, during June alone 154,000 yards of film (87| miles) were examined by the censor; and in July 173,000 yards (98 miles). , It is difficult to estimate the average cost of manufacturing a him, says the report, because the managers grossly exaggerate the fees paid to the artistes acting for the purpose of advertisement. However, it is a matter of common knowledge that M. Max Linder, the Film •tung, declares that he has received £40,000 in three years as cinematograph stage manager’ for a famous French firm. The same house produces sixty miles of m every week at a cost of £4OOO, which produce £320 of revenue weekly, or £16,000 a year.