“ARE YOU THERE?"

New Zealand Mail, Issue 1717, 25 January 1905, Page 59

“ARE YOU THERE?"

RECENT PROGRESS BY TELEGRAPH AND TELEPHONE. (“Morning Leader.") The simultaneous announcement of the success of th© experiments for ‘ superimposing" additional circuits on the underground telegraph AVires betAveen London and the North, and of the approaching trial by the Post Office of the rapid telegraph system, Avhich its inventors, the Hungarian engineers, Messrs Poliak and Virag, are exhibiting m London to-day, suggests that telegraphy in Eiigland is at last waking up. Apart from improvements in the construction of apparatus and lines, inland telegraphy, with comparatively small exceptions. has stood still for nearly 20 years. The apparatus noAV in use is the same in principle that excited the Avonder of our parents and grandparents —the Hughes printing apparatus and the "Wheatstone automatic on the most important lines, the Morse Sounder and Printer and the Single Needle and A.B.C. o*n the shortest lines.

The duplex method, by Avhich messages may be sent in tAvo directions at once, and the diplex, by Avhich two messages may be sent in the same direction at once, have been in use for many years; and even Delany’s Avonderful multiplex method, by which six messages may be sent oA r er a single Avire at the same time, was invented as long ago as 1886. NO DEMAND FOR BRAINS.

The reason of this practical standstill has been that telegrapli3 r is not an expanding service. The number of messages sent year by year shows rather a tendency to* decrease, and the system that served the last generation continues, therefore, to suffice fairly AA r ell for our present needs. Necessity is the mother of invention, and necessity, in the* sense of the pressure of a groAving business, haw been absent in the case of inland telegraphy. International telegraphy has been someAvliat more fortunate. Not to speak of improved methods of making and laying cables, the cable companies have been quick to try new methods of getting the best out of them. This is because the international service is expanding, and the great cost of cables —*say from A2OO to J?4OQ a mile —makes it necessary to increase the speed of Avorking, and consequently the capacity of the existing cables, rather than to lay new ones. But even inland telegraphy has shown signs of progress Avithin the last tAvo or three years. And the* impulse to progress has come chiefly from telephony. WAKING UP. It arises in this Avay. Long telephone circuits, in order to AA'ork satisfactorily, must be formed of “open" Avires. Wires in cables, Avhether overhead cr underground, Avork well for exchange purposes, because they are then comparatively short; but for trunk circuits betAveen distant towns they Avill not, under ordinary conditions Avork at all. And for every circuit tAvo Avires are necessary. How are Ave to get “pole-space?" Already the main roads and railways of Great Britain are carrying their full quota of poles—too many, perhaps, in the case of the roads. And the poles, as everyone may see, are practically filled with Avires. The only alternatives, then, are to make one Avire serve the purpose of two. if this can be done, or else to put all the telegraph Avires on the main routes underground. It is in connection Avith the first alternative that the experiments in ‘'superimposing" and the trials of the PollakYirag apparatus are being made. By a suitable arrangement of the sending and receiving instruments, two telegraph wires can be made to yield a third or “superimposed" circuit. And similarly two pairs of telephone Avires, forming tAvo circuits, can be made to form a third. MARVELS OF SPEED. Already, according to Sir William Pfeece. a speed of 450 Avords a minute, or 27,000 Avords an hour, is practicable. The Pollak-Virag apparatus claims a speed of 50,000 Avoids an hour, and actual official trials in Germany have shoAvn that it can Avork at a speed of 40,000 Avords an hour. If this apparatus could be brought into general use the number of Avires between the large towns might obviously be largely reduced. But even “superimposing” and more rapid apparatus are not. enough, and hence the second alternative of underground telegraph wires becomes necessary. Already a heavy telegraph caole has been laid on the main route between London and Carlisle, with branches east and west, and to this cable in course of time all telegraphic communications will doubtless be transferred, leaA’ing the ovehead lines free for telephones Are there, then, no conditions under Avhich a. long underground cable might be used telephonically ? Prof. Pupin, of the United States, says “Yes." He

affirms that by the insertion of induction coils at regular intervals on the cable it can be made almost as serviceable as an overhead line. The cost is rather heavy, but experiments show that the idea is a good one, and we shall probably hear more of it both for underground, and submarine telephony. THE LAST REQUIREMENT.

Speaking of telephony, one can hardly help mentioning the beautiful Poulsen telegraphone, which is now being put cn the market in a practical form. In this instrument the vibrations of the metallic diaphragm of a telephone receiver are registered on the* edge of a magnetic steel disc, AvhicJi revolves beneach th© diaphragm. If the disc is again made to reA r olve beneath a similar diaphragm, corresponding A’ibrarions are set Aip in the latter, Avhich may be heard, like the original vibrations, as spoken word. When the record is no longer required it may be removed by passing a strong magnet along the edge of the disc, Avhich is then ready to receive a neAV record. The telautograph is also a wonderfully ingenious recording instrument, which may be used in connection Avith an ordinary telephone circuit. By this apparatus one’s handwriting is reproduced in facsimile at the distant end, and thus two business men may at once record in Avriting a bargain Avhich they have nia.de over the telephone. It only remains to reproduce one’s features by Avire —a development Avhich some electricians are sanguine enough to expect—and then, surely, the ne plus ultra of electrical communication Avill have been reached.