Part 7

After leaving the main frame they are taken to the “intermediate distributing frame,” the central connecting point for various branches of the lines going to the switchboard, signaling and other apparatus. From the “horizontal side” of this frame, wires go to the switchboard, where they terminate in little holes known as “multiple jacks.” They also connect with the line and position message registers, where the calls from each Line and the calls handled at each operator’s position at the switchboard are recorded. The “multiple jacks” are additional terminals placed at necessary intervals throughout the switchboard, where they can be used by operators to make connections with any other line on the board.

From the “vertical side” of the intermediate frame Mrs. Smith’s wires reach the “line and cut-off relay,” an electrically controlled switch which turns on the light signal that appears on the switchboard when she lifts the receiver from the hook. This “line relay” also extinguishes the light when the operator makes the connection, or when Mrs. Smith returns the receiver to the hook.

[Illustration: A TYPICAL POLE LINE, WITH CROSS ARMS, IN THE COUNTRY]

The swift moving electric current that was set in motion when Mrs. Smith began the call, instantaneously passes through all these devices for safeguarding and protecting the subscriber’s telephone service. The light announcing Mrs. Smith’s desire to make a call is called the “line lamp,” and is flashing on the switchboard. Directly beneath it is the “pilot lamp,” which glows whenever any “line lamp” lights. With the “line lamp” is a “jack” or terminal, where connection can be made with Mrs. Smith’s line. This is the “answering jack.”

[Illustration: THE CABLE VAULT INTO WHICH THE CABLES PASS WHEN THEY ENTER THE EXCHANGE AND FROM WHICH THEY ARE LED UPWARD TO THE MAIN DISTRIBUTING FRAME]

When the operator sees the flashing signal of Mrs. Smith’s “line lamp,” she inserts one end of a pair of “connecting cords,” which are on the board before her, in the “answering jack” for Mrs. Smith’s line. These “connecting cords” are flexible conductors that put the wires of subscribers in electrical connection. Then she pushes forward the “operator’s key” directly in front of her and is connected with Mrs. Smith’s line.

The operator ascertains the number wanted and places the other “connecting cord” in the “jack” corresponding to Mrs. Jones’ line. If she finds she cannot herself connect with Mrs. Jones’ “jack,” because it is on another part of the board out of her reach, she makes a connection with another operator who can reach Mrs. Jones’ line. The second operator then makes the connection with Mrs. Jones’ “multiple jack” and places her line in connection with Mrs. Smith’s line at the first operator’s position. At the same time the first operator pushes the operator’s key back, thus ringing Mrs. Jones’ bell.

“Supervisory lamps” on the board before her, connected with the “connecting cords,” tell the operator when Mrs. Jones answers the summons. They flash when the connection is made and one goes out just as soon as Mrs. Jones takes the receiver from the hook to answer. If one of these lamps flashes and dies out alternately it tells the operator that either Mrs. Smith or Mrs. Jones is trying to attract her attention and she connects herself and ascertains the party’s wishes. When both subscribers “hang up,” both lights flash to indicate the end of the conversation. The operator then disconnects the cords from the subscribers’ “jacks” and presses the “message register” button recording the call against Mrs. Smith.

[Illustration: ROUTINE OF A TELEPHONE CALL

The subscriber, after looking up in the directory the desired number, takes the telephone off the hook, which causes a tiny electric light to glow in front of the operator assigned to answer his calls. (In some exchanges equipped with a magneto system, a drop is released by the turning of a crank.)]

[Illustration: The arrow indicates the light as it appears on the switchboard. Each operator can connect a caller with any subscriber in that exchange, but she is assigned to answer the calls of only a limited number of subscribers whose signals are these lights showing at her particular position.]

[Illustration: She takes up a brass-tipped cord, inserts the tip, or “plug,” into the hole, or “jack,” just above the light, at the same time throwing a key with the other hand in order to switch her transmitter line into direct communication with the caller, and says: “Number?”]

[Illustration: The caller replies by giving the name of the exchange and the number he wants, as for example, “Main 1268.” The operator repeats the number, “One-two-six-eight,” pronouncing each digit with clear articulation, to insure its correctness, and, if it be from a subscriber in the Main Exchange, she--]

[Illustration: Takes up the cord which is the team mate, or “pair,” of the one with which she answered the caller, locates the jack numbered 1268, and “tests” the line by tapping the tip of the plug for a moment on the sleeve of the “jack” to ascertain if the line is “busy.” If no click sounds in her ear she--]

[Illustration: Pushes in the plug and with her other hand operates a key on the desk. The first action connects the line of the subscriber called; the second rings his bell. When either party hangs up his receiver, a light glows on the switchboard desk, showing the operator that the conversation is ended.]

[Illustration: THE CENTRAL TERMINAL OF YOUR TELEPHONE

A MULTIPLE SWITCHBOARD]

[Illustration: THE BACK OF A MULTIPLE SWITCHBOARD]

[Illustration: THE BIRTHPLACE OF THE TELEPHONE, 109 COURT STREET, BOSTON

On the top floor of this building, in 1875, Prof. Bell carried on his experiments and first succeeded in transmitting speech by electricity]

How the Telephone Came to Be.

It is hard to realize that there was once a time, not so very many years ago, when the telephone was regarded as a scientific toy and hardly anyone could be found willing to invest any money in the development of the telephone business.

[Illustration: ALEXANDER GRAHAM BELL IN 1876]

[Illustration: THOMAS A. WATSON IN 1874]

The story of Professor Alexander Graham Bell’s wonderful invention is full of romantic interest and the early days of its exploitation were replete with dramatic incidents.

~THE MEN WHO MADE THE TELEPHONE~

Young Bell had come to America in 1870 in search of health, the family settling at Brantford, Canada. He numbered among his forebears many distinguished professional men. For three generations the Bells had taught the laws of speech in the universities of Edinburgh, Dublin and London. He himself was an accomplished elocutionist and an expert in vocal physiology.

During the year spent in Canada in regaining his health, Bell taught his father’s method of visible speech to a tribe of Mohawk Indians and began to think about the “harmonic telegraph.”

In 1871 young Alexander Bell accepted an offer from the Boston Board of Education to teach the “visible speech” method in a school for deaf mutes in that city.

For two years he devoted himself to the work with great success. He was appointed a professor in the Boston University and opened a school of “Vocal Physiology” which was at once successful.

He might have continued his career as a teacher had it not been that his active brain still clung to the “harmonic telegraph” idea and his inventive genius demanded an outlet.

[Illustration: PROF. BELL’S VIBRATING REED]

So we find him in 1874 working out his idea of the “harmonic telegraph,” the perfection of which meant a fortune to the young inventor. That he never realized his goal was due to the fact that while experimenting, he made a discovery which led to a far greater invention and one that was fraught with more benefit to mankind than the “harmonic telegraph” could ever have been.

It was while working with his faithful man Friday, Thomas A. Watson, in the dingy little workrooms on Court Street, Boston, that Bell got the inspiration which made him turn from the “harmonic telegraph” to devote himself to the invention which was destined to make his name famous--the speaking telephone.

~THE FIRST SOUND OVER A WIRE~

Mr. Watson has dramatically described the incident as follows:

“On the afternoon of June 2, 1875, we were hard at work on the same old job, testing some modification of the instruments. Things were badly out of tune that afternoon in that hot garret, not only the instruments, but, I fancy, my enthusiasm and my temper, though Bell was as energetic as ever. I had charge of the transmitters, as usual, setting them squealing one after the other, while Bell was retuning the receiver springs one by one, pressing them against his ear as I have described. One of the transmitter springs I was attending to stopped vibrating and I plucked it to start it again. It didn’t start and I kept on plucking it, when suddenly I heard a shout from Bell in the next room, and then out he came with a rush, demanding, ‘What did you do then? Don’t change anything. Let me see!’ I showed him. It was very simple. The make-and-break points of the transmitter spring I was trying to start had become welded together, so that when I snapped the spring the circuit had remained unbroken while that strip of magnetized steel by its vibration over the pole of its magnet, was generating that marvelous conception of Bell’s--a current of electricity that varied in intensity precisely as the air was varying in density within hearing distance of that spring. That undulatory current had passed through the connecting wire to the distant receiver which, fortunately, was a mechanism that could transform that current back into an extremely faint echo of the sound of the vibrating spring that had generated it, but what was still more fortunate, the right man had that mechanism at his ear during that fleeting moment, and instantly recognized the transcendent importance of that faint sound thus electrically transmitted. The shout I heard and his excited rush into my room were the result of that recognition. The speaking telephone was born at that moment. Bell knew perfectly well that the mechanism that could transmit all the complex vibrations of one sound could do the same for any sound, even that of speech. That experiment showed him that the complex apparatus he had thought would be needed to accomplish that long-dreamed result was not at all necessary, for here was an extremely simple mechanism operating in a perfectly obvious way, that could do it perfectly. All the experimenting that followed that discovery, up to the time the telephone was put into practical use, was largely a matter of working out the details. We spent a few hours verifying the discovery, repeating it with all the differently tuned springs we had, and before we parted that night Bell gave me directions for making the first electric speaking telephone. I was to mount a small drumhead of gold-beater’s skin over one of the receivers, join the center of the drumhead to the free end of the receiving spring and arrange a mouthpiece over the drumhead to talk into. His idea was to force the steel spring to follow the vocal vibrations and generate a current of electricity that would vary in intensity as the air varies in density during the utterance of speech sounds. I followed these directions and had the instrument ready for its trial the very next day. I rushed it, for Bell’s excitement and enthusiasm over the discovery had aroused mine again, which had been sadly dampened during those last few weeks by the meagre results of the harmonic experiments. I made every part of that first telephone myself, but I didn’t realize while I was working on it what a tremendously important piece of work I was doing.

[Illustration: WHAT THE FIRST TELEPHONE LOOKED LIKE

ALEXANDER GRAHAM BELL’S FIRST TELEPHONE]

The First Telephone Line.

“The two rooms in the attic were too near together for the test, as our voices would be heard through the air, so I ran a wire especially for the trial from one of the rooms in the attic down two flights to the third floor where Williams’ main shop was, ending it near my work bench at the back of the building. That was the first telephone line. You can well imagine that both our hearts were beating above the normal rate while we were getting ready for the trial of the new instrument that evening. I got more satisfaction from the experiment than Mr. Bell did, for shout my best I could not make him hear me, but I could hear his voice and almost catch the words. I rushed upstairs and told him what I had heard. It was enough to show him that he was on the right track, and before he left that night he gave me directions for several improvements in the telephones I was to have ready for the next trial.”

Then followed many heart-breaking months of experimenting and it was not until the following March that the telephone was able to transmit a complete, intelligible sentence.

[Illustration: TELEPHONE APPARATUS PATENTED IN 1876 BY PROF. BELL, PHOTOGRAPHED FROM THE ORIGINAL INSTRUMENTS IN THE PATENT OFFICE AT WASHINGTON]

On February 14, 1876, Professor Bell filed at Washington his application for patents covering the telephone which he described as “an improvement in telegraphy” and on March 3, of the same year, the patent was allowed.

That was the year of the Centennial Exposition at Philadelphia and Professor Bell had a working model of the telephone on exhibition. Tucked away in an obscure corner it had attracted but little attention, until on June 25th an incident occurred which had a tremendous effect in giving to the new invention just the sort of publicity it needed.

Professor Bell himself describes the incident in the following interesting manner:

“Mr. Hubbard and Mr. Saunders, who were financially interested in the telephone, wanted this instrument to be exhibited at the Centennial Exhibition. In those days--and I must say even up to the present time I am afraid to say it is true--I was not very much alive to commercial matters, not being a business man myself. I had a school for vocal physiology in Boston. I was right in the midst of examinations.

“I went down to Philadelphia, growling all the time at this interruption to my professional work, and I appeared in Philadelphia on Sunday, the 25th. I was an unknown man and looked around upon the celebrities who were judges there, and trotted around after the judges at the exhibition while they examined this exhibit and that exhibit. My exhibit came last. Before they got to that it was announced that the judges were too tired to make any further examinations that day and that the exhibit could be examined another day. That meant that the telephone would not be seen, for I was not going to come back another day. I was going right back to Boston.

~HOW AN EMPEROR SAVED THE TELEPHONE~

“And that was the way the matter stood--when suddenly there was one man among the judges who happened to remember me by sight. That was no less a person than His Majesty Dom Pedro, the Emperor of Brazil. I had shown him what we had been doing in teaching speech to the deaf in Boston, had taken him around to the City School for the Deaf and shown him the means of teaching speech, and when he saw me there he remembered me and came over and shook hands and said: ‘Mr. Bell, how are the deaf mutes of Boston?’ I said they were very well and told him that the next exhibit on the program was my exhibit. ‘Come along,’ he said, and he took my arm and walked off with me--and, of course, where an Emperor led the way the other judges followed. And the telephone exhibit was saved.

[Illustration: THE FIRST TELEPHONE SWITCHBOARD USED. EIGHT SUBSCRIBERS.]

An Emperor Wonders.

“Well, I cannot tell very much about that exhibit, although it was the pivotal point on which the whole telephone turned in those days. If I had not had that exhibition there it is very doubtful what the condition of the telephone would be today. But the Emperor of Brazil was the first one to bring that situation about at that time. I went off to my transmitting instrument in another part of the building, and a little iron box receiver was placed at the ear of the Emperor. I told him to hold it to his ear, and then I heard afterward what happened. I was not present at that end of the line. I went to the other end and was reciting, ‘To be or not to be, that is the question,’ and so on, keeping up a continuous talk.”

“I heard afterward from my friend, Mr. William Hubbard, that the Emperor held it up in a very indifferent way to his ear, and then suddenly started and said, ‘My God! it speaks!’ And he put it down; and then Sir William Thomson took it up and one after another in the crowd took it up and listened. I was in another part of the building shouting away to the membrane telephone that was the transmitter. Suddenly I heard a noise of people stamping along very heavily, approaching, and there was Dom Pedro, rushing along at a very un-Emperor-like gait, followed by Sir William Thomson and a number of others, to see what I was doing at the other end. They were very much interested. But I had to go back to Boston and couldn’t wait any longer. I went that very night.”

“Now, it so happened there, that, although the judges had heard speech emitted by the steel disc armature of this receiving instrument, they were not quite convinced that it was electrically produced. Some one had whispered a suspicion that it was simply the case of the thread telegraph, the lovers’ telegraph, as it was known in those days, and that the sound had been mechanically transmitted along the line from one instrument to the other. Of course, I did not know about it at that time; but when the judges asked permission to remove the apparatus from that location I said, ‘Certainly, do anything you like with it.’ But I could not remain to look after it; they had to look after it themselves.”

“My friend, Mr. William Hubbard, who had kindly come up from Boston to help me on this celebrated Sunday, June 25, said he would do his best to help them out, although he was not an electrician. He knew nothing whatever about the apparatus, beyond being in my laboratory occasionally, knowing me well. But he undertook to remove this apparatus and set up the line under the direction of the judges themselves. So they had an opportunity finally of satisfying themselves that speech had really been electrically reproduced.”

“Sir William Thomson’s announcement was made to the world in England, before the British Association, and the world believed--and from that time dates the popular interest in the telephone.”

In October, 1876, the first outdoor demonstration, in which conversation was carried on over a private telegraph wire, borrowed for the occasion, took place between Boston and Cambridge, a distance of two miles.

In April, 1877, the first telephone line was installed between Boston and Somerville.

A month later an enterprising Boston man put up a crude switchboard in his office and connected up five banks, using the system for telephoning in the day-time and as a protection against burglars at night. This was the beginning of the exchange system, all previous telephoning having been between two parties on the same circuit.

~NINE MILLION TELEPHONES IN U. S.~

Soon after exchanges sprang up in several cities, and by August of that year there were 778 Bell telephones in use. From this modest beginning the telephone has grown until on January 1, 1914, there were 13,500,000 telephones in the world, nearly 9,000,000, or over 64 per cent being in the United States.

[Illustration: MODERN DISTRIBUTING FRAME

When the wires come to this frame they are in numbered order in the cable. The main frame redistributes these wires so that they are arranged according to their call numbers, making it possible to connect any wire with any other wire anywhere that telephone service is installed.]

[Illustration: HOW THE WIRES ARE PUT UNDERGROUND

Breaking Up the Asphalt Pavement. First Step in Laying an Underground Cable.]

[Illustration: Laying Multiple Duct Tile Subway Through Which the Cables Will Run.]

[Illustration: Feeding Cable Into Duct as It is Being Pulled Through Subway from the Other End.]

[Illustration: A CABLE TROUBLE]

The use of the telephone instrument is common, but it affords no idea of the magnitude of the mechanical equipment by which it is made effective.

~UNSEEN FORCES BEHIND YOUR TELEPHONE~

To give you some conception of the great number of persons and the enormous quantity of materials required to maintain an always-efficient service, various comparisons are here presented.

[Illustration: TELEPHONES. Enough to string around Lake Erie--8,000,000, which, with equipment, cost at the factory $45,000,000.]

[Illustration: WIRE. Enough to coil around the earth 621 times--15,460,000 miles of it, worth about $100,000,000, including 260,000 tons of copper, worth $88,000,000.]

[Illustration: LEAD AND TIN. Enough to load 6,600 coal cars--being 659,960,000 pounds, worth more than $37,000,000.]

[Illustration: CONDUITS. Enough to go five times through the earth from pole to pole--225,778,000 feet, worth in the warehouse $9,000,000.]

[Illustration: POLES. Enough to build a stockade around California--12,480,000 of them, worth in the lumber yard about $40,000,000.]

[Illustration: SWITCHBOARDS. In a line would extend thirty-six miles--55,000 of them, which cost, unassembled, $90,000,000.]

[Illustration: BUILDINGS. Sufficient to house a city of 150,000--more than a thousand buildings, which, unfurnished, and without land, cost $44,000,000.]

[Illustration: PEOPLE. Equal in numbers to the entire population of Wyoming--150,000 employes, not including those of connecting companies.]

The poles are set all over this country, and strung with wires and cables; the conduits are buried under the great cities; the telephones are installed in separate homes and offices; the switchboards housed, connected and supplemented with other machinery, and the whole system kept in running order so that each subscriber may talk at any time, anywhere.

Where Does Sound Come From?

Somebody or something causes every sound we hear. Sounds are the result of disturbances in the air. Sound is produced by waves in the air. The buzz of the bumble-bee is caused by the quick movement of his wings in the air. The wings themselves do not make the sound, but their motion causes waves or vibrations in the air which produce the sound of buzzing. Every motion made by anybody or anything produces waves in the air just like the waves you see in the water--a big movement makes a big wave and a tiny movement a tiny wave. When you clap your hands you make a disturbance in the air which causes a sound--the harder you clap the louder the sound. You can hear this sound and anybody else near can hear it. If there were no air about us, however, we would hear no sound, even if we could live in such a condition of things, for it is the air waves produced striking against the drum of our ears that enable us to discern sounds. When we talk we make air waves also and thus produce sound. If you were deaf, and talked, you could not hear any sound, because even when there are air waves they must still strike against a sounding board in order to be recognized as sound--and the drum of our ear is our sounding board for hearing sounds.