WIRELESS TELEGRAPHY.

Press, Volume LVI, Issue 10387, 3 July 1899, Page 2

WIRELESS TELEGRAPHY.

ONE ACHIEVJEMENT OF SIGNOR : MABCONI. Regttlab CowanncAxioN Between a " Lightship and the Shobe. A letter from Mr J. A. Fleming, a professor in University College, London, which appeared in the London Times weekly edition of Aoril 7th, -will give the ordinary reader a better idea of how Signor Marconi manages "bo transmit telegraphic messages over comparatively- long distances without the use of a connecting wire than would any close scientific description. -It may be mentioned, however, oi the word "etberj" which tie professor employs in Ms letter, that it is used in the English language in two totally different senses.;, The first is as the name of a colourless liquid easily vaporised, whose vapor is used to allay pain. This liquid has nothing whatever with the subject, and should be put entirely out of the mind- The second use of the word (that made oy Professor Robinson) is as the name of a substance, colourless, unseen, and unknown, we will say—except in a theoretical sense —-which is supposed to fill all space. The original conception of this substance is as old as Plato's time; Newton, Descartes, all the beacon lights of science through the ages have assumed its existence, and all modern physical students accept it. The ether theory of the formation, of worlds must be familiar to many. In fact, up to twenty years ago, as the men of to-day who were then at the universities will -remember, the word ether was & familiar nante, a harmless Decesesoy conception, a great convenience in bringing a tremendous void in science which, nobody knew anything about, so far as could tbeu be eeenk ~ Following is the letter of which mentioQ ias been made above:—Duriog the last few day i tore been permitted to make a close 'examanetion of toe apparatus and methods r being employed by fciignor Marconi in his 1 remarkable telegraphic experiments between Sooth Foreland and Boulogne, and at the ' South Foreland Lighthouse have been allowed by the inventor to make experiments , and transmit messages from the station there established both to France and to the ligbt•lap co tfrs Qoodwiaflead*, which is equip*

; : ' i , ped ftjr sending and receiving ether wave t signals. Throughoufrthe period of my visit r messages, signals, congratulations, and jokes L wore freely exchangp between the operaj tors sitting on eithef side cc£ the Channel, i and automatically printed down intelegrapliic , code signals on the|ordinary paper slip at 1 the rate of twelve k> eighteen words a 5 minute. Not once was there the slightest j difficulty or delay ia obtaining an- instant - reply to a signal seiA. No familiarity with i the subject removes the feeling of vague . wonder with -which jpne see 3 a. telegraphic r instrument merely connected with a length I of 150 ft of copper wire run up the side of .a i flagstaff begin to draw its massage out of j space and print dowa| in dot and dash on tihe . paper tape the indigence ferried across . thirty miles of wate| by the mysterious ether. . I The public have already been placed in • possession by the Tones and other agencies' • of a general description of the apparatus em- ; ployed by Signor Marconi, and there is no , need, therefore, to enter into technical de- • tails. Within the last few days also various scientific men have invited to give the • public the guidance pi their opinions on th'e novelty and utility pf these demonstrations. ■ These criticisms ha\ji for the most part not i been of a very helpful character. The genera! public are nit much concerned with i questions of priority or with the claims or suggestions of rival* experimentalists; but they are interested k ascertaining the serious possibilities of that f hich iias been actually . achieved. Signer Jiarconi has never hesi- | tat-ed to acknowledge that ha luis built upon the foundations laid by others but a vast gulf separates labora ory experiments, how- , ever ingenious, from iractical large scale de- ' monstrations conduclsd with all that regularity and freedom ft «n failure which is the absolute condition oJ their public utility. I cannot help thin ring that *tlie time has arrived for a little tore.generous apprecia- j tion .by his scientific contemporaries of the' feet that Signor Mar oni has, by minute attention to detail, and by the important addition of the long vertical air wire, translated one method of |pace telegraphy out of the region of uncertain delicate laboratory. experiments and place 1 1 it on the same footing; as (regards certainty of action and ease of i manipulation, so far «s present results show, j as any of the other ni stfbods of electric com-1 munication employing ; a continuous wire be-1 tween the two This is no small j achievement. The apparatus, moreover, is ] ridiculously simple, aijd not costly. With ] the exception of the|flagstaff and 150 ft of : vertical wire at each Ind, he can place on a j kitchen .table the applj Lnces, costing not more than £100 in all, for! communicating across 30 or even 100 miles i>f chann-d. With the same simple means ihejihas placed a lightship-I on the Goodwins in ifestant communication, j day and night, with the South Foreland j lighthouse. A touch m a key on board the i lightship suffices to i ng an electric bell in ' the room ait South Fo "eland, 12 miles away,} with the same ease ant certainty with which one can summon theji servant to one's bedroom at an hotel. A| attendant now sleeps hard by the instruments at South Foreland. If at any moment he i$ awakened by the bell rung from the lightsljip, he is abie to ring up in return the Ran&sgate lifeboat, and, if need be, direct it to the spot whera its services are required ,within a few seconds of the arrival of the caUlforhelp. , In the presence of the enormous practical importance of this feat alone, and of the certainty with which comnmndeatiofi can now be established between ships mi. shore without cosily cable or wire, the scientific criticisms which have been by other inventors against Signor Marcoi i's methods have failed altogetfher in t&eir aj pxeciation of the practical significance of thf results he has brought about. ; T&E FIELD OF !iVTRELESS TELEGRAPHY. The fwblic, howevi r, are not in the least interested in learning he exact meed of merit to be apportioned U various investigators in .the up-building ofjthds result. They do, however, want to kfeow -whether the new method of communication across the Channel establMied by .tb| expenditure of a few hundred pounds will pake the place to any considerable extent of submarine cables which have cost many thoufends of pounds to lay and equip. They do also desire to learn what reasons, if any, prevea* every lighthouse and lightship tound our coast from being forthwith furmJaied with the necessary apparatus for placing it in instantaneous and secure connection with the mainland. They also hope to i; ear that the methods con be appKed to enable ships to be able in addition to ciknmundeate instantly in case of need "frith shore stations. To understand bow fir these things can be done, and to appreciate the necessary or present limitations of the method, it is requisite to explain that each vertical wire or rod connected to at Marconi receiving or sending apparatus has & certain "sphere of influence." Signor Marooni has proved by experiment up to certain limits that the distance to which effectfire signalling extends varies as the square of the height of the rod. A wire 20ft high carries the effective signal one mile, 40ft|hjgh four miles, 80ft sixteen, miles, and so on. Up to the present time hi baa not yet discovered ray method 'of shielding any particular rod so as to render it responsive only to sigaalt coming from one j

I station and not from all others within its sphere of influence. In 3pite, however, of what lias been said, there is no inherent im- , possibility in attaining, that desired result. At, present all signals sent from the South ■Forelfrfd.'to France affect.the receiver on board the Goodwin lightship. But this offers no difficulty. In an ordinary electric bell system in a hotel the servants recognise the room from which the signal comes by means of a simple apparatus called an indicator, and a very similar arrangement can be applied to distinguish the origin of an ether wave-signal when several instruments are at. 1 work in a common region. Subsequent in/-, ventions, as also, perhapa, the promulgation, of some necessary Bo.'trd of Trade regulations for the use of the ether t will prevent official ether-wave receivers from being disturbed by i vagrant electric waves sent out by unauthorjised persons in their neighbourhood. The 'practical upshot, however, of the matter, is that at present if more than two' stations are not established within certain regions, these stations pair and pair can communicate ; with-each other freely and regularly by means i iof ether-wave-signals "sent out and received j jbv long vertical rods or wires. No state of the atmosphere, and neither darkness or j storm, interrups so far as yet found the freej dom of communication, j Up to the present time none of the other I systems of wireless telegraphy employing • ! electric or magnetic agencies have been able 'to accomplish the same results over equal J distances. Without denying that much remains yet to be attained, or thai the same may not be affected in other ways; it is impossible for anyone to witness the South Foreland and Boulogne experiments without coming to the conclusion that neither captious : criticism nor official lethargy should stand in the way of opportunities being afforded for a further extension of practical experiments. Wireless telegraphy will not take the place of telegraphy with wires. Each I has a special field of operations of its own. I but the public have a right to ask that the j fullest advantage shall be taken of that par- ! ticular service which ether-wave telegraphy can now render in promoting the greater safety t)f those r.it.eea, arid that, in view of t our enormous maritime interests, this country : E-liall not permit itself to be outraced by ; others in the peaceful contest to apply the ! outcome of scientific investigation and dis[Coveries in every possible direction to the j service of those who are obliged to face the ' perils of the sea. If scientific resesrch has j forged a fresh weapon witn which in turn to i fight Nature "red in tooth and claw," all other ! questions fade into insignificance in comparij son with the enquiry how we can take the utmost advantage of this addition to our resources. It ia'stafed'that the French authorities are jso gratified with the success of the wireless ', telegraphy demonstrations between Boulogne j and the South. Foreland that an attempt to I telegraph from Paris is proposed, and that I the iiiffel Tower will be the French terminal. I The English terminal will remain at the South ' Foreland. The direct, distance between the two points is about 230 miles. The London "Daily Ntws" describes the method of sending and receiving messages. From the bye-road leading from St. Margaret's there is seen what looks like a coastguard signal staff, but closer inspection dis-> pels this idea. There are, in fact, three light spars lashed together to form one, which isplanted in the sward, and kept to the perpendicular by some score of stay ropes. It is thus a delicately-tapered, staff ~150 ft high from the ground. From the extreme top you observe what is apparently a light cord'slanting downwards across the lawn and path, till it disappears, through a, tightly-closed .sgaert'ure in the middle pane of a window on the ground floor of the house. This/; in fast, is the wire .attached to the receiving and transmitting instruments within doprs. £.iFajwthe length of this wire the message passes,* and then it is launched into spaee,tS find its swiffc way in fog," dwkrews,. rain* sniow, - storm*; for wireless, telegraphy is independent, of wind B!nd weather, whatever they may be. . ' ; - As tie electro-magnetic .waves, after travelline .through the ether with, the speed of light, are capable of influencing conductors at a distance, it is easy to see that signals can be sent in this way. The first to do so in a practical manner wa£ Signor Marconi, a mere boy of 21. Marconi produces bis waves in the ether by electric sparks passing: between four brass balls. The balls are electrified by connecting them to the well-known instrument called an induction coil, and as tfa"e working of the coil is started and stopped by an ordinary telegraph key for interrupting the electric current, the sparking can be controlled according to the Morse code.