SCIENCE and INVENTIONS.

New Zealand Herald, Volume LX, Issue 18297, 13 January 1923, Page 8 (Supplement)

SCIENCE and INVENTIONS.

WHEN BRAKES SQUEAK. Squeaking brakes are usually the result of dirt working its way into fabric brake lining. This foreign material presents a hard surface to the metal drums, and tb© result is friction of sufficient intensity to causa the unpleasant noise. Usually the brake linings can be effectively cleaned with kerosene;" but in cases where there is a larg® amount of dirt or grit a small quantity of resin and castor oil mixed to a plastic condition and applied to the brake bands will be more effective in overcoming the noise*

CANARY HEARD 1000 MILES AWAY. The largest audience that ever listened to a grand opera has heard, in New York, and outside it in a radius of a 1000 miles, well-known artists and the full chorus and orchestra of the Metropolitan Opera House 1 sing " Aida." From a vast drtu hall of the National Guard, where i the opera was sung in oratorio temto HWU crippled war veterans and 14,000 otner persons, it was broadcasted to no fewer than 600,000 radio receiving sets. Special efforts had been made to that the music and voices should, be heard distinctly, and they were, the amplifiers having been tested with the aid of canaries, whose trills had been heard clearly throughout the entire 1000-mile area.

NEW SOAKING WONDER. An entirely novel type of flying craft, winch is to bo called the "wind-boat, is now in design, and is to be built first in Germany. The boat will have curiously curved sails, which will be so disposed that tha boat will swing automatically head on to any rising current of air. This will mean that once launched, it will? «' sail " itself in the aerial ocean, "tacking" to and fro of its own accord, and rising from crest to crest of invisible "waves," until it has gained a high altitude above the earth. Whereupon the air sailors steering their " boat by a big rear-rudder like & ship, will sot off on a long, swift glide in the direction they wish to go. These." wind-boats" will, it is declared, correspond in-aerial navigation to the sailing-ships of tile sea. 1 " SUPER " SEWING MACHINE. A statement in which no woman can fail to be interested is to the effect that a Boston man has invented a sort of super-sewing machine which will relegate even the most modern of automatic stitchers to the background. The new contrivance will not only perform all the operations that the ordinary .- sewing! machine accomplishes to-day but a good many more in addition. Its. inventor claims that much of the hand labour now necessary on the best class of machinemade goods can neatly and efficiently by the machine, which will sew on, trim, and finish lace edgings, insert lace trimmings, make French and complete the rest of the "complicated finishing that no sewing machine has yet "been able to tackle, and all this will be done in a tenth of th© time demanded by present methods. PETROIi FROM COAL, A discovery which may be of very great importance to the British coal industry— conversion of soft coal into liquid oil—was the subject of a lecture delivered to the Mining Society of the University of Birmingham by Dr. F. Bergius, an eminent German research chemist. The process is simple. To" coal under a very .nigh pressure the gas hydrogen is added, and tha result is that 90 per cent, of liquid oil is obtained. By various modifications'of the process it is possible to produce petrol or other kinds of mineral oil. A process. which would enable a largo part of the British coal reserves to be thansmuted into liquid fuel would secure Britain against any risk of. a liquid fuel famine and enable it to make its own oil at home. Hydrogen for such processes Is generally obtained by decomposing water, (a combination of hydrogen and oxygen) with electricity, and its price will depend on the cost of« electric power.

SAFES THAT ARREST BURGLARS. Science has always played a leading part in the war against crime, and o«s of her newest surprises for the cracks* men is a* safe which automatically defends itself . against his attacks. The modern criminal does not /try to pick the lock of a safe; he knows that to attempt to do so is useless He either blows up the lock with explosives or burns a hole in the walls of the safe with the oxy-acety-lene flame. In the burglar-proof safe is placed a tiny glass bottle containing in liquid form a.gas that stupefies but does not kill. The. bottle is so deli cat* that a rise in temperature causes it to break and set the fumes free. As soon as the burglar, turns on his oxy-acetylene torch "he hears the clink of breaking glass. Next moment he begins to get drowsy, and before he knows what is happening he is sleeping peacefully, beside the. safe that he; was cracking! ' Next morning he is found with the most complete evidence of his guilt, caught redhanded by the safe itself.

PULPIT 'PHONE TO PEWS. A telephone system between the pulpit and the pews, by which deaf persons in the congregation will be able to hear the preacher, is about to be introJticari into on KaAthonrna chnrp.h. 'J'hft Presbyterian Church is a large one, end the Rev. James Beid is one' of the most popular preachers in the town. It has frequently --been suggested by seat-holders suffering : from deafness that the managers might, do something to assist them to hear better, and the question of ( insteJling a telephone system Is now being dealt with by a committee. A transmitter will be placed hi the pulpit. This, being a .very sensitive instrument, will pick up the preacher's voice even, when it is being used very softly, and will carry the sound waves along a wire to receivers placed for every seatholder who wishes to have one. When not in use the receivers can be hung in front of the pew scats. It is likely that the use of th« system will not be confined to those suffering from deafness, as there are always a large number of people who take notes/ of . Mr, Reid's sermons to whom it would /.be useful.

LONG-DISTANCE TELEPHONY. At the present moment a telephone subscriber in New York can get connection with a subscriber in San Francisco and carry on satisfactory conversation. The magnitude of. the technical achievement which this possibility represents cannot better be illustrated than by mentioning the fact that New York is about the same distance from San Francisco that London is from Bagdad. It is hardly necessary to say that a London subscriber cannot ring up Bagdad. The remarkable longdistance telephone system which has been built up in North America has no counterpart in Europe, although with the denser population it might be supposed that conditions for such a development would be more favourable in Europe. An obvious explanation of the relative backwardness of long-distance telephony, in Europe is furnished by the language difficulty. That this explanation is, however, not uniformly accepted is illustrated by Mr. _ Prank Gill's reference to it in his presidential address to the Institution of Electrical Engineers. Mr. Gill stated " that the opinion of some of those well qualified to judge is that the difference in language and customs do not, as they would at first sight appear to do, constir tute a serious bar to international communication by telephone, and there are weighty reasons such as the present necessity of improving the relationship between nations, in addition to the normal commercial advantages, which render it safe to forecast sufficient through business to warrant - the setting-up of a competent organisation with the plant necessary to handle th* traffic..'-'-