SCIENCE AND INVENTIONS.

New Zealand Herald, Volume XLV, Issue 13925, 5 December 1908, Page 4 (Supplement)

SCIENCE AND INVENTIONS.

SLOT TYPEWRITERS.

Slot machine typewriters are to bo placed ' in, the rooms of the loading hotels of America, so that guests can attend to their correspondence. The machines are the result of a. new invention by which a ten-cent, piece (fivepence) dropped into a slot allows the machine to be used for half-an-hour. THE HIGH AIR. Meteors prove that the air is still dense enough to make those little bodies incandescent through friction at a height. v of 100 miles; but up to the present, man has succeeded in exploring the atmosphere to a height of only 16 miles. The greatest authentic height attained bv a human being is 35,500 ft. Kites have flown to a height of 21,000 ft, and an unmanned balloon, carrying recording instruments, has reached 85,000ft—a little more than 16 miles. THE PERFECT KETTLE LID. There is a remarkable degree of assurance in the name by which this new idea is known, but even if not perfection it is a great improvement on the older type of lid. Who has not heard the wail of "All over my clean hearth " when the kettle has unexpectedly boiled over and the subsequent rush to remedy the evil often results in scalded, hands. This new lid has a mouth or vent by which the excess of steam can escape, thus obviating the shortcomings of the ordinary lid in everyday use. SEWAGE DISPOSAL. The Royal Commission on Sewage Disposal, appointed in 1898, has just issued its fifth report, which deals with the relative merits of the various methods available for the purification of the sewage of towns. The conclusion of the Commissioners is that it is practicable to purify the sewage of towns to any degree required, cither bv land treatment or by artificial filters, and that there is no essential difference between the two processes, for in each- case the purification, j so far as it is not mechanical, is chiefly effected by means of micro-organisms. The main question for, decision, the Commissioners say, is, therefore, which system can be most economically adopted. CROPS BY ELECTRICITY. In opening the Natural History Museum at Hanley, Sir Oliver Lodge said that for tli© past "three years he had been trying the electrification of crops, which was not a new process, on a larger scale than before, and by this means t&ey found that wheat crops yielded 30 or 40 per cent, more grain than they otherwise would have done on the same land and in the same season. Although it was too early to make a dogmatic statement, it might vbe that electrification did the same sort of work as the sunshine. They could not grow the same crop year after vear on the same soil, because it would be exhausted. It used to be thought that this was because the plant had taken something out of the soil, but now it began to be mooted that instead of taking something out it had put something into the soil, that it had secreted a poison to which other plants might be immune bub by which the same crop would be damaged. SAWING THROUGH BUILDINGS. An interesting article in the Scientific American gives two illustrations of the recent application of the method of sawing stone invented by Francois Eugene Chevalier in 1854. The cutting of the stone is accomplished by an endless wire cable, which, carries water. and some abrading powder. It is the latter, which may bo fine sand, which actually acts as the teeth of the saw. In the first example, a church in Munich, the stone foundations were sawn through horizontally. The dampness of the foundations had led to the absorption of moisture through the walls by capillary attraction.- The sawing through was undertaken to cure this. The saw was combined with a machine which inserted sheet lead as the cuts were made. We have here the efficient means of curing damp walls in buildings. The other case is that of a four- ; storey building in the Rue St. Roch, Paris, which was sawn through from top to- bottom. The saw consisted of an endless twistI ed wire cable, on to which small jets of water carried fine sand. ■ In this way the solid stone was sawn through, and by repeated cuts a slice two inches thick* was taken from each side of the facade, and the same from the piers on each side. The object in this case was to isolate from neighbouring buildings. V ; GAS ENGINES FOR WARSHIPS. Recent experiments by the Marquis of Graham on the disused gunboat Rattier, wiSh gas engines in place of the ordinary steam engines have attracted the greatest attention in naval circles, and there are many who believe that we are oh the brink of a revolution in the construction of battleships. Not only do gas engines take up far less room, but they require less coal bunkers, and perhaps most important of all, a de- ■ creased number of men in the stokehold.' So impressed are the authorities with the result(of these experiments that it is under consideration to order gas engines to be placed in one of the new torpedo destroyers to be laid down under this year's construction programme. The engines of the Rattler were designed by Messrs. W. Beardmore, of Glasgow, who have long held the opinion that this was the type of engine most suitable for the warships of the future. An important point in connection with these engines is that no smoke is given off, so that a fleet could travel, almost undetected —a thing that is almost impossible when steam engines are employed, owing to the dense volumes that are emitted from the funnels. It is understood that* Messrs. Beardmore are prepared to experiment with a larger set of engines if the Admiralty will provide the necessary facilities. ' GAS IN CYLINDERS. A recent development in Germany should offer great possibilities in this country. It is the supply of gas in cylinders adapted for the lighting of country houses and rural districts. The gas has been invented by Herrmann Blau, a chemist, and is, says Chambers' Journal, distilled from oil and other materials. Manufacture is carried out upon new and novel lines. The oil is fed into the retort and distilled at a lower temperature than that employed in coal-gas manufacture. The by-products are secured, and the gas cleaned and scrubbed in the usual manner. It is then compressed at great pressure in cylinders similar to those employed for the transportation of oxygen, the effect of this pressure being a liquefaction of the gases. The permanent gases , which distillation has yielded, such as hydrogen, methane, and carbon monoxide, the '' chief constituents of coal-gas, are then dissolved to the required extent in the liquid gases. When the pressure is relieved, the liquid volatilises, carrying off a certain proportion of the gases which were dissolved. The light obtained is of great brilliancy, ; while the gas is perfectly pure and harm- '' less. The cylinders are of varying lengths - and capacity, it being possible to acquire a ' small vessel holding one pound of gas, suit- .'' able for travelling, boating, or camping-out expeditions, up to large reservoirs contain- ! ing heavy supplies suitable for extensive country seats. The medium size, adapted for use in small villas, will supply enough gas to meet requirements for some eight ] weeks. All that is necessary to do is to in- i stal the charged-cylinder in ( the receptacle ; supplied for the purpose outside the build- " ing, connect it up to a small tank in which ; the pressure is regulated, and then admit it to the ordinary piping-system of the house, When a cylinder is empty it can be easily ; and quickly disconnected* and a full cylin- ' der replaced, the empty one being return- ] ed to the works for a fresh charge. There < is no possibility of explosion, and no tech- j nical knowledge is necessary for its mani- i pulation. In Germany several villages are 1 being lighted upon this system. The dis- i tributing mains are laid in the usual manner, though small pipes need only be used, and are connected up to a small hut in . which the gas cylinders are placed. The only attention required is the changing of i the cylinders as they become exhausted. The system is cheap, highly efficient, and : free from danger, and even the smallest vil- 1 lagea_can. become possessed of a complete i iJSas-distnbution plant at a nominal outlay ]