SCIENCE, MECHANICAL INVENTIONS, ETC.

New Zealand Herald, Volume XXXIX, Issue 11950, 26 April 1902, Page 4 (Supplement)

SCIENCE, MECHANICAL INVENTIONS, ETC.

TO FERTILISE WHEAT LANDS. A ccniors echo of Sir William Crookes' prophecy at Cliftonthat the time was approaching when the wheat supplies would be insufficient for the world'* food—was heard at Lord Rayleigh's last lecture. In the course of it Lord Rayleigh exhibited the apparatus which Professor* Ramsay and he Bret used for separating.argon from the nitrogen which customarily dilutes it. The apparatus consists, in some of its details, of a large glass sphere in which are two good-sized platinum electrodes. The propel lies of the induction current through the electrodes it was one of the purposes of Lord Rayleigh's lecture to discuss; hut the point with which we are at present concerned was the appetite which the flame between the electrodes exhibited for the oxygen and nitrogen with which it was fed. Such was the speed of consumption that the experiment had suggested to another investigator the possibility of forming nitrates by this method, feeding the electrodes with air instead of with oxygen and nitrogen; and he was inclined to believe that the method might prove commercially practicable. It was Sir William Crookes' opinion that the starvation of the world might be arrested if some artificial means could be devised for fixing nitrogen, and by so doing to fertilise wheat lands up to a point of higher production. The earth's stores of nitrates will not always be sufficient. Artificial nitrate might give another face to the problem. Sir William Crookes put the requirements of the world at 12.000,000 tons of nitrate a year. Electric nitrates may easily become a more important manufacture than that of synthetic indigo. To the manufacture of fixed nitrogen—in the form of nitrate of sodaan interesting rider is the speed at which the world is dissipating this material. The nitrogen which we liberate with a light heart in a battleship broadside has taken millions of minute organisms patiently working for centuries to win from the atmosphere. In a modern naval battle in which there were sixty line of battleships and cruisers engaged, each of which expended on an average forty tons of cordite, the total volume of nitrogen set free would be three hundred and two thousand four hundred cubic meties, or about three hundred and eighty tons, equivalent to two thousand three hundred tons of fertilising nitrate. On the other hand there presses on every square yard of the earth's surface a volume of nitrogen equal in Weight to seven tons. Unfortunately it is.in a free state. The fertiliser wants it fixed.—Morning Post. ' SHOOTINO STARS. Shooting stars are comparatively near to us when we see them as silver streaks of light; in fact, the distance separating us from these bodies at the time of their extinction is. generally speaking, no greater than that of Loudon to Brighton. The distance of the stars is so enormous that the bare recital of the figure? conveys no adequate impression on the mind. " The distances are not to be reckoned in hundreds, or even thousands, of miles. Indeed, a million of miles is insufficient for the purpose of expressing the distances of these bodies. Twenty-five billions of miles separates us from the very nearest stara gigantic orb, visible only in the Southern Hemisphere, and known as a Centauri—that is, the brightest star of the constellation of Centaur. It must not be imagined that shooting stars are common to the neighbourhood of the Solar System only, for the great ocean of space teems with them. They are scattered everywhere, from the remotest stellar system to that of which the sun is the mainspring. And they are very small bodies. The majority of them Would turn the scales at a few ounces.—English Mechanic. THE MARINE STEAM TURBINE. , The Parsons Company have at present in hand a torpedo-boat destroyer with a similar speed to the Viper (now being built to the order of the Admiralty) which will have a less consumption both in cruising and full speed than any other 30-knot boat.in the English navy. This vessel, the Velox, was launched just recently on the Tyne, and measures 210 ft long,' 21ft beam," with a moulded depth of 12ft 6in, and to guard against " buckling" she has been specially ' "stayed" longitudinally. The Velox, to ', ensure economy at cruising speeds, has j fitted in her a novel arrangement of power wherein engines of the ordinary reciprocating type are designed to work"in conjunction with, and are coupled direct on to, the steam turbine, the turbines being kept in reserve for the higher speeds only. In considering coal consumption it will be seen at once that the engine arrangement introduced by Mr. Parsons form a very important item, because, as in the case of torpedo-boat destroyers, but a. small percentage of their steaming is spent on fullspeed work ; and also, as is well known, as all steam engines (steam turbines included) do not work so economically when running much below the power for which they are designed. For the long periods on which these boats are simply cruising about the coal consumed is only that of the two small triple compound reciprocating engines, the steam turbines not being utilised, thus reducing the "cruising - ' coal consumption to a minimum which, when running at full speed, is only increased bv the low consumption derived from the use of the steam turbine. The marine steam turbine forming, as it does, "one of the most striking developments in the historyof marine engineering," is largely adopted by private enterprise; but. as Engineering points out, " it is a little surprising that at present no vessel is in progress fitted with turbine machinery and built for the Royal Navy."— TO RENDER FELT WATERPROOF. Dissolve 1 liter of good, pure, linseed oil i (not varnish), 1 liter of petroleum, £ liter of 1 turpentine. 125 grammes of yellow wax, the 1 latter in small pieces, in a vessel, preferably of copper, over a bright coal fire, avoiding, however, a boiling of the mass, for fear of hie. With this hot solution saturate the felt, naturally as far removed from the tire as possible, hanging if up or spreading it out afterward in a warm, dry room in such a manner that th temperature acts uniformly on the surfaces. WHY PLANTS BECOME LIMP. Everyone must have noticed thai in very not weather in summer leaves of plant* frequently flag or lose their stiffness and become quite limp during the heat of the day —only to recover again in the evening though no rain has fallen in the meantime J his occurrence frequently puzzles the uninitiated, who are under the impression that plants absorb much of the moisture which they contain through (he medium of their leaves. As a matter of fact, practically none of (he water in plants makes its way thereinto through (he medium of the leaf. All the water is absorbed through the minute roothairs which the plant, sends in all directions throughout the soil. The leaves, however, give of! very large quantities of water through the medium of the stomata or minute openings with which they are so abundantly furnished, and it is because the leaves evaporate or transpire more moisture through these minute holes than the tiny roots are able to absorb from the soil that the plant collapses in the manner indicated. The stiffness, or. as scientists term it, the tuigidity of a. growing plant is almost entirely due to the pressure exerted by the water contained in the minute cells of which the tissue or substance of the plant is built up. it is the loss of this water by evaporation that causes a plant, after being pulled and thrown aside for a couple of hours, to become so limp.Fanner's Gazette. THE TirKHAraiTK) IXFUrEVCF, OP SFF.NERY. The medical man in his study of climatology is rather apt to limit his 'mental vision. In the selection of a suitable health station for his patient he oftentimes directs his whole attention to the physical characters of the place, and forgets to consider the probable influence of the natural features of the district on the mind of the invalid. The action of psychological impressions is not infrequently of quite as great importance as any alteration of physiological processes. Indeed, it must not be forgotten that much of the advantage of " a change" often arises from the readjustment of the psychical life of the patient as well as the rectification of physical conditions. The wise physician cannot afford to neglect this matter, and as an aid to a wider outlook we venture to recommend a careful study of Lord Avebury's charming new work, "The Scenery of lingland and the Causes to Which it is Due."— Medical Press.,