OCR Text |
Show t B Mechanism of wireless telegraphy. I The accompanying Illustration shows Messrs Kemp and llradfield operating the Wlmeresux end of the Marconi wireless telegraph system, which It now In constsnt and perfeet opersllon between Wlmeresux near Boulogne, and South Foreland, England, a distance dis-tance of thirty-two miles, across the English channel, The wire which ran he teen apass-Ing apass-Ing through the window of the office terminate at Ihe top of a matt which la more thai) ISO feet high and atanda strnment Tery much like Ihe stock ticker which every one has seen and most people understand Professor Herts gives a concise and Intelligible description ot the transmlttsr and receiver re-ceiver Invented by Marconi, as follows fol-lows "The superiority of Marconi's apparatus ap-paratus Is Isrgely due to Its simplicity The transmitter consists of two small brass spheres fitted In an Insulated case and halt Immersed In oil for the regu-Isrltlng regu-Isrltlng of the emitted radiations, one adjacent to the office. A similar mist Is rigged near the office In South Foreland, Fore-land, and It It from the top of each ot these masts thst communications ra-dials ra-dials through th air without th further fur-ther aid ot wires. The moat astonishing astonish-ing ftaiure ot thla new method ot telegraphy Is that Intervening buildings, build-ings, fogs, rain, snow, hills or ships do not Imped the accuracy or speed of th Invisible radiations which emanate from the wire on one meat and are taken up and registered by the disconnected discon-nected wire at the peak of another matt thirty-two miles away. The characters In which messages thus txpressed are th familiar dots and dashes ot the old Mors code, and thClllustratlon shows the, receiving operator op-erator reading a message from th tap There It he beea written by an Int end being connected to earth, the other with an elevated conductor The current cur-rent li supplied with a powerful Induction In-duction coll, controlled by a Morse key. Thus, the waves that travel abroad, as the sparks pass between th globular terminals, are Impressed 'ab Initio,' with communications In the familiar fa-miliar 'dot and dash' alphabet "Marconi's receiver Is of an exquisitely exqui-sitely Ingenious type. Its vital part Is the minute Instrument called by Dr, Lodge, who In 1881 modified It, a 'coherer;, 'co-herer;, by M Dranly, who lo 1M0 Invented In-vented It, a 'radio-conductor.' Aa used by Big. Marconi, It I an axhausted glass tube, less than two Inohes long and one-tenth ot an Inch In diameter, with aealed-la conducting wires, separated sepa-rated by a shallow laysr ot nlokel and sllvsr filing. These In their ordinary, loose state are almost perfect Intola- BBJ tors, but no sooner are they Impinged HB upon by Hertslsn. waves than they co- BB here and conduct. Dr lodge describee tjV th effect as 'a singular varlst) of B electric welding' In which 'th eno- BB menlsry electric quiver acts as It K H were a flux' A highly aensltlve de-, fOg. lector Is thus obtained, and Itt ienH MB llveneis Is Increased by the attachment PH to It ot an Insulated wire raised to flK height ot about 1(0 feel, which serves SOftf to collect vibrations running to wast H in the sky Ths restore- Kfc3 Hon to the coherer of Kg? Its detective efficacy 1 MHK brought about by the auto-i ggflj malic action of a tapperJ WP started hy the passing oft HK the current, which loosen) B metallic particles In the. tube, and renders them H once more nonconductlr. Hfl The alternate makings and KB breakings of the circuit at longer and shorter Inter- Hfl SI I geafl i awawas valt, corresponding to dot aa dash Hfl ot the rode, are the means by which. Hfl the messages Intrusted many mils Hfl away to the ether are delivered. The Hfl current (idled I Indeed to feeble dl- rectty to do the work require ot It, Bfl but It suffice lo actual a dsllcaU re- Hfl lay by which a mors powerful baU HJ tery Is thrown Into ths circuit" Hfl |