TELEPHONY.

Timaru Herald, Volume XXVII, Issue 1765, 27 June 1877, Page 4

TELEPHONY.

(Daily Telegraph.) Tbat astounding force, electro-magnet ism, is now employed, not only m tho transmission of visible symbols, but also of sounds ; and sonic enthusiasts confidently announce — whether on sullicient grounds we do not presume to assert — that telephony is destined to supersede telegraphy. JBy a coincidence whicli lias sometimes occurred m other departments of scientific exploration, tbere are simultaneously two explorers m the telephonic field, both of whom, after having been hard at work on the new invention for several years, have at length succeeded m demonstrating that it is practicable. Professor A. Graham Bell, of the Boston University, has constructed a telephono on one principle, and Mr Elisha P. Gray, of Chicago, another on a different system ; and though it may bo impossible at present to forecast all the specific purposes to which the invention is capable of being applied, extensive scope is certain to be found for its use. The earliest attempt to transmit sound by electricity was made by JReis m 1861, and the improvements effected m the same direction since that period are reported to he more remarkable than thoso which distinguished tho results accomplished by Wheatstone and Morse m telegraphy, as compared with tho crude experiments of Le Sage, 03 years previously. It may, therefore, bo inferred that, as the principlo of telephony ia now scientifically comprehended, tho perfecting of tho apparatus is only a question of time and labor. Professor JJBell successfully demonstrated his system for the first time six months ago on a wire extending from Boston to Cambridge, over a distance of two miles, when tho words articulated by the operator at tho latter placo could be distinctly heard at tbo former and vice versa, the dialogue being conducted m the ordinary vocal tones. Moro recently a bolder experiment was made upon a wire 18 miles long, between Boston and Salem ; and m January last, Professor Bell had. brought his instrument to so sensitive a pitch that he was able to transmit tho inflections of tho human voice. Tho well-known song " Tho Last Rose of Summer," was so exactly rendered that not a single note was lost or confused m the passage. Tho sounds communicated aro described to hava been as clear as if the listener were " at the rear of a concert hall, a hundred feet from tho singer." Laughter, applause, and instrumental music were subsequently transmitted, and tho sounds are said to have been so minutely exact that " a violin could be distinguished from a violincello." The maximum distance hitherto bridged by Professor Bell is one hundred and fortythree miles, and tho instrument rapidly attains a higher state of efficiency. The report of a lecture was, for the first time, despatched by the samo process from Salem to Boston. On that occasion speeches wero sent from the latter to the former city, and the applause with which they were greeted m Salem was distinctly beard at Boston. Tlie experts of that city are now addressing themselves to tho more serious task of talking through wires of collective diameter corresponding to that of an average ocean cable ; and, though certain obstacles havo yet to be Burmounted before vocal inflection can be transmitted across tho Atlantic through so thick a medium, the fullest confidence is entertained that these difficulties will be entirely overcome.

The mechanism of Professor Bell's apparatus consists of a powerful compound permanent magnet, to the poles of wbicb aro attached ordinary coila of insulated wire. In front of tbe poles is a diaphragm of iron, and a mouthpiece whose function is to converge the sound upon this diaphragm. When the human voice causes the diaphragm to vibrate, electrical undulations are induced m the coils around the magnets precisely similar to the undulations produced by tbo human voice. Theso coils are connected with the line wire, and the undulations caused m thorn travel through the wire, and, passing through another instrument at the opposite terminus of the line, are again resolved into atmospheric undulations by a metallic diaphragm similar to the one already described. Mr Gray's instrument is not constructed for the purpose of conveying promiscuoas sounds, as m tho former case. It is, ontbe contrary, represented as a " telephonic piano," and itself produces the sounds which it transmits. It has already been tested on a wire uniting Chicago and Milwaukee, distant about 85 miles, and several airs p?rformed m tho latter city were distinctly recognised by the audience assembled m the former, and the performance elicited rapturous applause. Since that trial a distance of 284 miles, between Chicago and Detroit, has been achieved, and that experiment is said to have been entirely successful. A transmitter and a receiver constitute Mr Gray's principal apparatus. The 6rst of these consists of a keyboard of two octaves and a tuning-bar, an electro-magnet and electro-circuit. Vibratory molecular action is communicated to the iron by magnetisation when the keys of the instrument aro struck. The receiver at the other end of the line consists of alarge " sounding-box," on which is mounted an electro-magnet. Obviously, however, the invention of Professor Bell is susceptible of the greater variety of uses. Still, for the purpose of journalistic reporting the balance of advantage appears for the present to lie with ordinary telegraphy. Apart from private telegraphic communication, occasion may Bometimes arise when the heart of the country throbs under a great common impulse, and when the inhabitants of Birmingham, Manchester, and Glasgow might be unusually anxious to become immediately acqtiainted with the proceedings of a public meeting held m tlie metropolis. In that case gatherings might assemble m these towns and listen at one time to the speeches as they were being delivered at St. James or Exeter Hall. Some Americans confidently hope to anticipate the period when a musical entertainment may be given m Berlin, and, at the same time, audiences may be collected at St. Petersburg, "Vienna, Paris, London, and New York to listen simultaneously to the singing v and playing. Indeed, a concert on Mr Gray's principle was duly announced to be held during the present month, the performance to tako place m Philadelphia and the audiences to assemble m New York, ninety miles distant.