SCIENCE and INVENTIONS.

New Zealand Herald, Volume LX, Issue 18380, 21 April 1923, Page 8 (Supplement)

SCIENCE and INVENTIONS.

-...-■■A- WIRELESS WARNING.The reliability and safety of the British air services to the Continent are due in no small measure to'the provision of wireless apparatus which enables constant communication to be maintained with land stations. On a recent occasion an aeroplane leaving London lost one of the wheels from its undercarriage, shortly after rising -. from the : ground. The accident was not, of course, noticed by the.pilot, but he received information of it from the land . station, and this warning enabled him to make a safe landing on the one remaining wheel by tilting his machine. NEW GREASE-PROOF PAPER. Paper can be * made grease proof by coating or impregnating with sugar. The sugar is applied in gelatine, with the addition of a hygroscopic agent such as glycerine, and of alum or other hardening substance. After the application of this preparation the paper dries quickly. The product is claimad, by the authority who supplies the suggestion to have a bright, smooth surface, free from stickiness, and to be flexible, more or less elastic, odourless and colourless. It is s4id to have no harmful action when used for wrapping food materials —but what of the alum ? POOD METAL DISCOVERY. Cobalt and nickel have not been classed with the elements essential to food plants, but their quite constant occurrence in minute' quantity has been lately shown by two European ' chemists. Twenty plants were examined, the parts used as food being preferably selected. They included carrots, onions, potatoes, spinach, lettuce, apricots, .'tomatoes,, beans, such grains as wheat, oats, buckwheat, and maize, and one fungus. \ Nickel was found in all of these products, in proportions ranging from one part in 100,000 in tomatoes up to one part in 500 in peas. Cobalt was missing from carrots and oats, and the quantity in other vegetables varied from one part in . more than 200,000 to three in 10,000 in buckwheat. /■•-■■: ■:'"—. ■ * NEW BRITISH TRAIN FERRY. . During the war considerable .use was made of train ferries between Great Britain and the Continent, mainly under conditions which—although excellent for war purposes not offer, satisfactory opportunities of profitable use for ordinary commercial purposes. A new enterprise has, however, been set on foot for a train ferry between Harwich and Belgium on a definite business basis. Harwich has been chosen not only because of the considerable traffic to the Continent, but also because the tidal rise and fall is very small and there is ample depth of water at all states of the tide. The train ferry boats to be utilised are those which were employed for war purposes. They, have a length of 350 ft., and are propelled by triple expansion engines at a speed of 12 knots. Ihis interesting equipment is expected to be in full operation before the end of the present year. ' HAIRPIN AS PICTURE HOOK.

An artist recently exhibited a large number of small, framed watercolour sketches in a small country town not able to boast of an exhibition hall suitable for the purpose. The school-house was used for the purpose, and when it came to hanging the pictures, those in charge decided that nails should not be driven in the walls. As nearly a hundred pictures were to be exhibited, the artist was puzzled to know what to ,do, but finally hit upon the following scheme: He bought some of the heaviest hairpins he could find and made a double bend in them somewhat after the form of a picture hook. Then he purchased some "lattice " moulding and suspended pieces at various heights along the wall by cords attached to the ends and fastened to hooks at the top of ' the- wall. The hairpin hooks were then hung over the edge of the lattice and the pictures hung in the projecting parts.

MACHINE TO FIND INSECTS. ■ An ingenious apparatus has been invented for sorting insects from the soil. . The machine was made to supersede the laborious method of crumbling up the soil on sheets of. paper, and then .waiting for the insects to move. ; The apparatus is the invention .of Mr. ; H. M. Morris, of : Rothamsted Experimental Station, .Haypenden; It consists of an upright galvanised-iron box in which are three shelves. On each shelf rests a large sieve. Each sieve has a different-size mesh, the one at the top having the largest, the"one", at the bottom the smallest. Fixed to the top of the box is a pipe terminating in a large rose. •„A sample of the soil to be examined is put into the top sieve, then water is rapidly sprayed on to it through the rose. Fourteen pounds of soil can be washed down in about 40 minutes. When the washing has been completerd only stones and the soil fauna remain in the sieves—all. sorted out according to size. And the insects axe mostly none the worse for their unexpected tubbing. NEW RAILWAY WAGGON BRAKE. The traditional form of railway goods waggon had a brake lever on one side only, so that the shunter' had frequently to cross over the line at considerable risk to get at the lever. Out of this arose a demand for some kind of appliance• which would enable the brake to be applied from either side of the waggon; and several solutions of the problem, more or less satisfactory, were tried. , The most satisfactory of all appears to be one which has been thoroughly tested on a British railway for'the. past two years. The brake can be operated by two short-hand levers at diagonally opposite corners of the waggons. The mechanism is so designed that the brake is very rapidly and efficiently applied simply by pulling down the lever.' Once the brake is set it is practically locked in position and cannot be released until the lever is definitely moved up again. By an ingenious device any wear in the brake blocks is taken up, so that repeated adjustment is not required. Although the pressure which the shunter 'exerts on the lever is only about 601b., the brake i block itself exercises a pressure of 60001bs.— which is enough to give efficient braking and not too great to produce skidding. This new brake can be adapted to power braking with air pressure or vacuum systems. ■ '?;.;"■ ' ".;,

THE "X " IN X-RAYS. As is often the case with great scientific discoveries, Rontgen only won the race for immortal fame by a short head. A certain Dr. Glendinning, of Melbourne, had arrived at practically identical results . as Rontgen, without so much as having ever heard his name, and had actually posted notes on them to England when the news of the German's discovery arrived When Rontgen, while experimenting with a highly exhausted vacuum tube, found that certain substances were made luminous, in spite of opaque objects between them and the tube, he called the rays which caused the luminescence X-rays," X standing, as usual, for the unknown quantity. Since then the X has been solved at least, there is general agreement that the rays are no different in nature from those of heat, light, radium, and " wireless." All are ether waves or vibrations, differing intrinsically only in frequency, and X-rays, recording to this theory, are able to penetrate opaque substances because they are so short (or of such -high frequency) that they are not detracted or reflected as light-rays ere. , But we still call them X-rays rather than Rontgen rays. Few discoveries have had greater consequences. First in medicine and then in industry, it enabled us to sec inside tilings without pulling them to.pieces It contributed largely toward the formulation of the new theory of matter mid atomic structure, and its combination with the spectroscope bis given science 1 a wonderful weapon, capable of analysing equally well the constituents ,of- a" dye and of a star, '