THE TELEPHONE. A GREAT INVENTION AND ITS ANNIVERSARY.

Progress, Volume II, Issue 10, 1 August 1907, Page 381

THE TELEPHONE. A GREAT INVENTION AND ITS ANNIVERSARY.

The bell rings, a voice says in an authoritative tone " No 3421," and the drama of domestic life begins to unfold itself before you. " Have you any nice fish this morning." After a pause — " But it must be fresh." Evidently the fish is fresh, fish always is fresh in the mouth of a fishmonger. But the house wife is still not content. "It mustn't be in the freeze. You know I can't bear the freeze." The pause that follows is long enough to convey the information that the fishmonger thinks so too, together with all the supporting references to all the saints and virgins of the past month's calendar. " Then send me three nice soles : and let them be here not later than half -past seven." In this manner all your tradesmen file before you as you shave and dream of breakfast. It strikes you as all very natural. Presently you take a hand yourself. The postman has brought a letter early telling that your best friend will be in town from Canterbury this very day, but the best

ground and kill the weeds and prune the branches. It will doubtless astonish all this world of men and women to be reminded that the instrument is scarcely thirty years old, that its initial invention, that which started the whole story of its wonderful development, is one of the great prize inventions of science, and that the subsequent discoveries are all examples of the greatest that is in the power of human wit, ingenuity of resource and enterprising courage From first to last there never was such a story as the story of the telephone, opened so brilliantly by Professor Graham Bell in the }~ear 1876 with as wonderful an introduction as any story has ever had on this planet. The professor is now a regent of that great scientific assembly of talents known as the Smithsonian Institution ; he is also expresident of the National Geographical Society ; he is full of years and honours, he numbers troops of friends, there are about him hosts of worshippers of his splendid intellect and of these hosts the extended order covers the globe. All this he has won by the strength of his character and the power of his mind. But in that not so far off day when he contrived that famous inlioduction to the story of the tele-

voice impulse, but the result was nothing, not even a voice. He concluded for the moment that his proper line was multiplex telegraphy and away he went after the multiplex in full sight of his friends who cheered the energy and enthusiasm of the young man. Accident however, saved him from the permanent desertion of his mother idea. A biographer relates how one day a wiie snapping in two sent a sound through another wire which had attached at each end a thin sheet iron disc a few inches in circumference. Experiment promptly made proved that this could be repeated ; and after that there arose in the enquiring mind of the youthful professor the epoch making question " Can vocal sounds be transmitted thus ?" The apparatus for the answer was put together quick as thought. Two small cylinders of metal each with a parchment diaphragm stretched across : inside each cylinder two magnets, their poles wound with wire and, between the magnets, a small strip of soft iron : a soft iron button in the centre of each diaphragm ; and lastly, a wire connecting the two cylinders. The professor's assistant took his station in the basement of the professor's house holding one of the cylinders : the professor marched up to the attic with the other, while the assistant paid out the connecting wire

That is the question," he humourouslysoliloquised. Brazil was charmed and said so. The Commissioners left off scoffing and the telephone became the prize hit of the great Exhibition. One of the clauses of Bell's wonderful patent is as follows :, " The method of the apparatus for transmitting vocal sounds telegraphically, as herein described by causing electric undulations, similar in form to the vibrations of the air accompanying the said vocal and other sounds substantially as set forth." This was the notice to the public that the instrument they were invited to use for ordinary communication would transmit every inflection of their voices one to anothei . But when the first exchange was established in 1877, it was found that the magnet transmitter was not sufficient for business needs, and the Bell Company sought to apply battery power. Edison here flashed into the field and, with his caibon transmitter added, led the world fox some time. The foundation of his success was the discovery of the French physicist, Count de Moncey, that " when two ends of a severed circuit are brought into contact, the resistance of the contact is variable with and proportionate to the pressure between them. The next step forward was made by Edison and Berliner who acting separately combined the induction coil with the transmitter. In 1878, Professor Hughes of Iyondon proved, with his microphone that to obtain, the best results with resistance changes due to changes of pressure, it is necessary to have a light contact. From that time all transmitters have been on the light contact plan. Before this, iron had been substituted for the parchment of the first diaphragms, and the thickness fixed at one hundredth of an inch ; experience having proved that thinner sheets were shrill, and thicker confused. The Blake transmitter followed the discovery of the microphone, but sensitive as was that transmitter at short distances it was found to be useless as the distances increased. A ruck of inventors at this juncture jostled one another for the discovery of some expedient to get over that difficulty. The lucky one proved to be a clergyman quite unversed in electricity. The Rev. H. Hunnings, u&ing granulated carbon, gave clear talking at long distances and his transmitter could stand high battery power. But very soon the granules were found to be liable to pack, thus stopping the passage of sound. Investigation revealed the fact that the electric current heated the transmitters. More space was given and the packing ceased. The best transmitter, the White solid back transmitter, followed, in which the packing is avoided by the insertion of a mica disc, the carbon granules occupying only part of the space between the electrodes. The receiver has a simpler story of development. The essential parts of the present receiver consist of magnet, air chamber, diaphragm, ear- piece and case ; the airchamber giving increased distinctness to the voice speaking through the transmitter. But the new telephone was not complete with the perfection of the transmitter. There remained the problem of long distance. In the beginning the Bell company guaranteed communication up to twenty miles. To-day men talk freely 1700 miles apart with as much ease as across an office table. The first difficulty was the attenuation of the very weak currents used. After much experimenting and the granting of many patents, Professor Pupin, of Colombia University, demonstrated that " inductances distributed at certain

intervals along a telephone wire strengthened the current greatly." Accordingly slight coils of wire (copper with iron core) ten inches in diameter, were fastened, four miles apart to the line, and these receiving the electric current were found to send it on undiminished." That cured the trouble of attenuation. These rings treble the capacity of telephone lines. As distances of telephony grew longer it was found that iron wire could not be used profitably. Copper being tried could not be tightened sufficiently, and the invention of Doolottle, who succeeded in hardening copper wire, so as to enable it to stand almost the same strain as iron, simplified matters. Interference was the last of the troubles, and this was got over by twisting the wires. Professor Bell discovered that if two wires of a circuit be wound about each other, interference (induction) cannot occur, as outside currents passing into the twisted wires are neutralised. Thus the first and the last of the inventions of the first thirty years of the telephone are Bell's Of the multiplication of exchanges and the improvements in the handling of their multitudinous wires it would be tedious to speak at length. Of the thousands of patents taken out for the betterment of various details of telephones and circuits it is impossible to speak at all. The chief aspiration is still unfulfilled. It is for the complete removal of the attenuation which has been partially got rid of so far as the establishment of the 1700 mile limit of long distance telegraphy. When complete success is attained men will be able to talk from Paris to Pekin and from Pekin back to Paris by the other side of the globe. A few figures are interesting. There are in the United States alone in use some six millions of telephones, and what may be the number in the world may be imagined from the fact that the telephone has spread over Europe, Canada, all the Americas the British Empire not forgetting India, Burmah, China, Abyssinia, Persia, Turkey, Siberia, and other countries too numerous to mention. Of these the United States, as becomes the birthplace and cradle of the inventior, stands pre-eminent. Berlin has one telephone to every seventeen families : Paris one to 22 : I^ondon one to 58 : New York one to 12 : Boston one to 6 : and San Francisco (before the earthquake of 1906) one to 4. The rise and progress of the telephone compressed as it is into the limits of a single generation make one of the most fascinating stories in the history of human achievement. But for the initial discovery of Graham Bell that story would have been impossible.