SCIENTIFIC DEVELOPMENTS

Otago Daily Times, Issue 18465, 28 January 1922, Page 6

SCIENTIFIC DEVELOPMENTS

PEACE AND WAR MACHINES: THE SAFETY PETROL TANK. (From Oue Own Corsesi?ondznt.) LONDON, December 13. In July, 1914, the greatest range over which wireless messages could be sent with reasonable cert)inty was about 5000 miles. To-day, practically the greatest possible distance between any two points on the earth’s surface is the span of the wireless instrument. , • The first press message to' be forwarded by Wireless direct, from England to Australia was sent by the Daily , Mail to, its correspondent at Sydney, at the invitation of the Marconi Wireless Telegraph Company. The ’message, despatched was: " Wannest greetings to you and all our kinsmen under the Southern Cross. ■ May this first direct wireless press message, to Australia be the harbinger of that closer, communication between Mother Country ‘ and Australia, which is wish nearest heart newspapers both countries.” It 'took only about one-sixteenth of a. second to send the message to Australia from Carnarvon, a distance of more than 12,000 miles. It Was sent on the now highpower valve transmitter, which was regarded by the Imperial Wireless Committee as the “system of the future.” The thermionic valve through which the message passed consists of an electric lamp in a very high state of exhaustion. The vacuum of the lamp is very much higher than that of ordinary lamps. The filament portion is surrounded by metallic cylinders, the inner cylinder takimr the form of a grid. These act as magnifiers. There are 48 of them in the transmitter, and each is a little bigger than an ordinary Rugby football . The current is interrupted into dots and dashes of the Morse code through the transmitter. The wave length was between 13.0C0 and 14,000 metres, and the message travelled at the rate of 186,000 miles per second: News was subsequently received from Australia that the message had been picked up at an experimental station of the Amalgamated Wireless (Australasian), Ltd., at Koo Wee Rup. near Melbourne, and at a Government wireless station at Perth. Owing to very bad atmospherics (electrical disturbances) the message was hot received in Sydney, where the receiving _ stations, owing to the shortness of their aerials, were not so well fitted for the purpose: of receiving this as were the Koo Wee Rup experimental station and the Government station at Perth. THE MYSTERY WIRELESS SIGNALS. Recent developments in wireless telegraphy were reviewed bv Senator Gnglielmo Marconi in his address as president of the Birmingham and Midland Institute. Given sufficient power, he said, it should be-quite possible to transmit speech wirelessly between England :and America. The linking of a telephone circuit to an already existing ordinary telephone exchange was tjuito easy, and from this arose the interesting possibility that eventually a. man sitting in his office, in London could call up a friend in Chicago or Washington. Referring to fears which had teen expressed .as to wireless horrors that might be expected if there should be another war, Senator Marconi'said that means of counteracting any snob developments would -be quickly found. He also derided the notion that persons could be injured mentally and physically by using them against their will as receivers for wireless waves. Electric waves, such as were used for wireless telegraphy or telephony, had' no more effect on the'human body or mind, he said, than starlight or moonshine. Senator Marconi attributes! to a slight misconception of some remarks which ho had made the sensational reports in the press, that Tie .had received wireless signals which he thought might have come from the planet Mars. He had stated at various times that undoubtedly efleets resembling signals of great wave lengths'wero occasionally registered by wireless receivers—effects coming apparently from somewhere in space—and these observations had been confirmed by many wireless observers. When, . therefore, ho was called upon to affirm absolutely that the signals in question did not come from Mars he refused. How could he know? How could anyone know? The signals came from 'outside the earth. Apparently they might come from the upper reaches of the atmosphere. They might be caused by some magnetic disturbances in the sun; they might come from Mars or from "Venus even. “ As a matter of fact,” ho added, “ these’ effects have not been nearly so noticeable of late; and I sincerely hope that the gentlemen of the press will not interpret this last remark of mine to* mean that I assert that the Martians, in despair at receiving .no reply to their , signals. have given up the attempt, probably thinking that our state of civilisation is so low that they had bettor wait several thousand more years before repeating the attempt.” TANKS AT FLERS. Tanks and tactics were the subjects of discussion at a meeting of the Royal United Service Institution. Lieutenant-colonel W. D. Croft (Scottish Rifles' maintained that the tank had changed the war of movement. The new queen of battle was not the infantry arm, but the tank. The Germans hod led the way by using the machine gun as an offensive weapon, but the tank could gain ground (fa the machine guns, afforded cover, and increased: the morale of the troops. The tank crew, unlike the infantry, had a definite object, and were keen on it. He held that a nation which trusted in swift tanks could beat the nation which trusted to cavalry arid infantry, provided there was perfect aerial control. Infantrv would in the future bo auxiliaries to tank. They had been since an airman sent that extraordinary message: The, lank is moving ud the High Street of Tiers with half the British army cheering tehind it.” General Lord Horne Mid the lesson to be learned was that we should never, cease from studying how tactics should be adapted to new weanons. Personally, he held that the man with the rifle was still the important person in modern warfare. At Flers the tank commanders wanted to fight the battle , themselves; they would have been better advised if they had had infantry with them. The real mess-go from Flera was that the tanks were followed " by a disorderly rabble,” and they were only saved from being driven back by the action of a certain bris-ade .major. Major-general Anderson pointed to the probable future of the tank as involving a contest, ns in the navy, between guns, armour, and speed. Further, it would no doubt be necessary to reckon with armoured aeroplanes, carrying guns, men, and mppSeo. Thai night be a long way

off, hoi they must look beyond the immediately practical future. The present „ state of affairs showed the helplessness of infantry withouttanks. ' . ' TALKING KDTEMA, . : A demonstratioh of the synchronisation ! of sounds' reproduced by the gramaphone with'motion pictures was given at a Lon--1 don hall recently by Mr C. H. Verity. ■ A film of a man singing, ior instance, was - , thrown on to the screen, and as he formed r his words in the picture, a gramaphone a few yards away reproduced them in exact synchronisation. One felt it..was.a.; most useful instrument for the repetition of political speeches, or comic monologues, or . even for short comedies, but the limitations ■ .. of, the' gramaphone will prevent the I use of. this invention as an aid to serious kinema art. The' apparatus,, which stands behind the screen, is electrically, connected with the projector at the other end of the hall. Two parallel rows of moving, lights aro fixed in; front of the operator, one registering the speed of the projector,. tha other that of the reoqrd;. and as long as these lights are travelling exactly together the operator knows that the syn- 1 chronisation-is perfect. FIREPROOF PETROL TAKES. 1 Very severe tests are in progress with 1 ! the object of obtaining an aeroplane petrol tank- which will not leak, burst, or take fire m the even of a crash or when hit by incendiary bullets. In the preliminary teats tanks are .being subjected to crash; conditions far 5 more' severe than those probv most accidents, even very had • ones. Indeed short of a fall from a great height, . completely out of control, or . * fall due to strootnral eoQopse in the. air,'| the teats are more severe than those occurring in practice Three prizes are offered-rooo of- £I4OO, one of £400; and one of : £2OO . The competition has. attracted 19 British, three French, one American, > one Belgian, one Italian, and one Japanese f entrants. i For the crash test each tank sms fitted' ) 1 into an aeroplane fnaelage frame, the front 1 of ‘.which contained a concrete weight representing the engine. This is a condition e representing the small aeroplane, in which * . a crash usually drives. the tank against tha > , engine, so that it is almost .certain to * - buret. In the large passenger ‘ aeroplanes the tanks are .usually. away, from, the engines. Between-the end walls of two ad-[ joining disused airship sheds a long-guide-' way has been erected, so that from *• height of 100 ft the' tanks descend at \ an angle of . 45dog, gathenr.r momentum, I and finally alighting on hard pressed sand. I Their speed at the moment of impact is I tremendous. The fuselage is ' found ranker* [ up and partly buried in the bard pressed > sand. ..„ I . Tanka already tested ere: CO Meases I Beasley, Simms, and Morris; this j is called » ' “safety balance/' tank." It consists of throe concentric shells : of thin. , steel, with rubber between ■. each of the shells; whilst between the inner f one, which holds “the petrol, and the next I one to it are shock-absorbing springs. The ' epaoa ijetwren the shells is lin. (2) Mr J. Gibsonr. -v steel tank consisting of three' separate (compartments divided by two transverse bulkheads. (3) Mona Bramson: \ a tank made up of an envelope which con- 7 sists of fabric, a light .spongy rubber, and I very fine woven wire.. The tank is mounted j in a shock-absorbing contrivance, and in a I crash runs forward a few inches, spending ( its momentum harmlessly. Very great inlerest is being taken in this L i eombetifcion, which is the first' of its kind. } ' The Air Ministry has no intention of ao-< quiring or claiming sole rights to any of I the successful designs; nor is there shy guarantee that orders will be given. TheS. .whole' world should benefit if perfect sue- 1 cess is obtained, and the successful maker r would, no, doubt, reap a far. ijipher reward | than the prizes. " j 1 WHERE FRANCE LEADS. , | " England; like France, contains huge areas 1 of land.the subsoil of which is either chalk It or limestone, yet, according to Mr A A. r Hudson, E.C., in a paper, on “The Relation J of, Soil to Plant Growth,” read before the J Purveyors’ Institution, when ho wanted f authoritative guidance on the subject ’of plant,, growth “when influenced by the pro- , sefico or absence of lime,” he had to turn, to Franco to find it 4 Twenty years' ago ne : acquired some land on a chalk sab-soiL A few failures due to lack of knowledge to the trees and. shrubs that would thrive-'* on such a • soil set him inquiring. There j were a few books available which contained { lists of suitable plants, bat they seemed i to have been copied from one book into sn-i* other, or where that was not the case they i differed in material respects.- Persons who i sold the trees were unable to _ help. and 1 many' plantings were lost Ultimately a *j found a French book in which the anther! referred to about " 400 publications, mostly in French, relating to the influence of .soil) upon plants, and from that time he began 1 to collect most valuable information. Thew study of soils in relation to plante,_ sad in f particular connection with the .chemical 000-« stituents of the soil, was considered by the.French'authbritioa to be of the highest rm-! portanoe.. The French had realised, morel • thoroughly than' the British bad, that eciea-. tifio investigation was neoeaaary .if tbe soil* was to produce the best results. Briefly P stated, the grading principles of tho French f nation in regard to land were three: fl)! Highly cultivate rich land; (2) afforest poos' land; (3) reclaim waste. In later" years much more information had been avaikute in the books and papers of English and . American botanists about the osoology <* r plants, and from these and other eonreee—/ mostly Fronqh and Gorman, and some Irish —he had extracted everything he could find! 'on the subject. Mr Hudson has "come to m opneanaon. that the theory which some botanists had advanced that the distribution of plants j depended entirely upon the physiaal— l chemical—properocs of the ami, was now almost exploded. Mops. Mootejeaa’s inves.l tigations had; shown dosdy That salt and \ lime were by " far the most important soil 1 ingredients in regard to their mfluenoe on I the distribution of plants, and that for all I 'm practical purposes it waa the presence o*i ■ absence of these in the iofl which vtas the ,i “ predominating, land in some esses the sole. V influence deciding the presence or absence f of certain plants in a given area.

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