George M. Shaw

“ If he had an order for any of his inventions, and, after having made a part or all of them, he invented an improvement, nothing would do but he must incorporate it, even though at his own expense. At last, finding that the close attention demanded by his manufacturing business was incompatible with the freedom demanded for invention, he abandoned it, and, two years ago, bought a site for an experiment-shop at Menlo Park, on the Pennsylvania Railroad, twenty-four miles from New York, a mere flag-station, with about a dozen houses, mostly his own and his workmen's. ”

“ The position was the dread of operators; the New York man was one of the fastest senders in the country, delighted in victims, and in this instance sat at his instrument with a grim satisfaction, waiting to open on the "new man," and chuckling with his Boston comrades over their expected fun. They commenced, and the New York man crowded his sending-speed to his utmost, with never a "break" by the new man receiving. At the end of the message, the astonished and exhausted New York operator adds, "Who the deuce are you, anyhow?" ”

“ Actual contact of one wire with another would spoil the business altogether. A wire bearing an electric current seems to be for the time surrounded, to an undefined distance, by an electric atmosphere, and all wires coming within this atmosphere have a current in an opposite direction set up in them. This is as near an explanation of the phenomena of induction as the state of telegraph science at present affords. Now, the telephone works with a very delicate magnetic current, and is easily overpowered by the action of a stronger current in any wire near which the telephone-wire may come. ”

“ We have thus proved, in a simple way, that a musical tone is produced by rapid, regular vibration, as shown by the marking—the air-waves, set up by the vibration, seeming to blend in the ear in a manner similar to that in which the vibrations of the string blend to the eye, which makes the tone seem continuous. ”

“ It is because the different positions of the mouth resound to different overtones. While some vowel is sung we hold different resonators to the ear until we find the overtones. They must be the cause of the vowelizing of the tone sung. To prove it we take a tuning-fork vibrating the note of that vowel's overtone as found by the resonator, and, holding it in front of the mouth, we shape the mouth until it resounds to the tuning-fork. Keeping the mouth in this position, we sound the vocal chords, and the result is the vowel, thus proving that that particular overtone is its stamp. ”

“ The Associated Press wires run through his laboratory, and anon he picks up his telephone and chats with Philadelphia, or with Prof. Barker, at the University of Pennsylvania. When visitors call to see him, they are most likely to inquire for Mr. Edison from the man himself—a boyish face, an unostentatious manner, a careless dress, and, in fact, the unchanged whole that formerly put in an appearance as the new man at the Boston office. The crowd of farm-boys that come over to see the wonderful talking-machine find him as ready to gratify their curiosity as the more pretentious "professor." ”

“ Every syllable and every turn of melody of such a song as 'My Mother bids me bind my Hair,' sung by a lady at one end, or 'When the Heart of a Man,' sung at the other, could be distinctly heard, but with the effect before noticed, that the voice was muffled or shut in, as if the singer were in a cellar, while it was not always possible to say at once whether the voice was that of a man or a woman. ”

“ When it is remembered that the principle of the telephone is that the sound-caused vibrations in the filmy diaphragm at one end create similar but magnetically-caused vibrations in the diaphragm at the other end, and so reproduce the sound, it will be obvious why the rapid roll of the ABC currents, or the swift sending of the fast-speed transmitter, when brought by induction into the telephone-wire, cause disturbances in the sound-vibrations, and thereby cripple the instrument. ”

“ But it is to be noticed that the experiment, interesting as it is, hardly comes under the head of a telephone, what is reproduced at a distance being not sound but motion.
"Obviously the invention cannot rest where it is; and no one more readily than the practical telegraphist will welcome an instrument at once simple, direct, and reliable. Even in its present form the telephone may be successfully used where its wire is absolutely isolated from all other telegraph-wires. ”

“ On applying the ear to a telephone joined into a circuit working in such an office, a curious sound is heard, comparable most nearly to the sound of a pot boiling. But the practised ear could soon separate the boiling into distinct sounds. There was one masterful Morse instrument—probably on the wire lying nearest the one on which we were joined up—whose peremptory 'click, cli-i-i-ck, click,' representing 'dot, dash, dot' on the printed slip we read from, could be heard over all. ”

“ The magnet is then shoved in, till it nearly touches the plate c c. After joining the ends of the spool-wire to the line-wires f f, that run to another instrument just like it, the telephone will be ready for use. It is important to concentrate the voice upon a narrow space at the middle of the plate, and for this purpose a movable wooden mouth-piece, a a, is used, with an opening at the bottom about the size of a dime. This mouth-piece should fit neatly, and reach to within about one-eighth of an inch of the diaphragm. ”

“ The farther they go the more they spread, and the weaker they become. A strong voice may be heard at an eighth of a mile, or about 700 feet. As sound travels 1,100 feet per second, it follows that, in less than a second after being spoken, the waves become too weak to make words. Let us be quick, then, to find what they are saying. Sun-waves, spreading from a focus, may be brought again to a focus by condensing them with a lens. So the sensation-waves, which spread from a focus, may be brought again to a focus by condensing them with an ear (Fig. 12) . ”

“ It is easy to see that each one would recover his own balance by pushing against the one behind him, and so the fall-back movement would be seen to pass like a wave through the crowd, each one passing it on as it reached him. In like manner, the push of the expanding gases, at the explosion, was transmitted to the church, the intervening air only passing the push along. ”

“ In Boston Mr. Edison fixed up a small shop and continued his experiments, which he put into such practical shape that he saw more money in them than in his salary. He worked out the idea of his duplex telegraph, and went to Rochester in 1870 to test it between that place and Boston. The effort failed, though Mr. Edison says it ought to have succeeded. He then came to New York, scarcely knowing what to do next. He hung around the office of the Gold Indicator Company, studying their cumbersome apparatus. One day some part of it failed in a time of excitement; Mr. Edison offered to remedy it ”

“ The telegraph was much longer regarded as an impracticable invention, and it is impossible to say how soon the telephone may not take rank among the necessities of common life. If we may trust the analogies of experience, its difficulties are certain to be overcome, although it will probably never meet the exaggerated expectations of many people. ”

“ In this experiment we notice that tones are high or low, according to the number of their vibrations—the higher the tone the greater the number of its vibrations per second. Again, we observe that we can make the same tone loud or soft, without making it higher or lower. We notice that loudness is obtained by striking with greater force, making the string or fork swing farther from side to side, but still swing the same number of times in a second. ”

“ If the bar be of steel, instead of soft iron, it will be magnetized and attract iron just as before; but, unlike the soft-iron bar, it will keep its magnetism and attract the iron even after the battery is removed. Its magnetism will be permanent. Since, however, electricity made the magnet, we can, in turn, make the magnet a source of electricity. Suppose the magnetized steel bar has attracted and is holding on to a piece of iron. We can now take the battery away and join the ends of the wire, as in Fig. ”

“ Everybody knows that sounds are propagated through the aerial medium by waves that travel swiftly from their sources, and that we hear them because the waves strike in rapid succession upon the drum of the ear. ”

“ A simple noise being a sound-wave, has its wave-form or make-mark. The blending of many such would produce a tone in that likeness; hence, a musical note is a blending of like noises, and every noise is really the first wave, the key-note of a musical tone. Take the ringing of a door-bell. Here the ear hears not only a musical tone, a sound-blend, in the ring of the bell, but also the noise of the clapper's clang, clang, clang. The vibrations of the bell throw the air into musical waves, shown in Fig. 5, while a huge clang-wave will sweep
Fig. ”

“ An air-wave is made up of a compression and a rarefaction—a push and a stretch—the two being produced in one vibration of the prong, the compression by the motion from a to a', and the rarefaction by the reactive motion from a to a". On its way back to a, the prong lets up on the stretch, and goes on to a' with another push, and so on as long as it vibrates. These compressions and rarefactions, represented in the figure by its shadows and lights, correspond to the crests and hollows of water-waves. ”

“ AMONG the innumerable uses of electricity none is more remarkable than its employment for the transmission of sound. The ultimate mystery of the action we cannot, of course, undertake to explain, but the mechanism by which it is produced is by no means difficult to understand.
If a wire, from a galvanic battery such as is shown in Fig. 1, through which a current of electricity is passing, be wound around a piece of steel or soft iron, as represented in Fig. ”

“ We cannot explore the nerve-waves, but, projected in the air, they become a picture that we can study. First there is the rough breathing or tremor h, then the mouth tunes itself for the musical tone o. Suppose the o to be made in a man's voice at a pitch A, below middle C. The o-making overtone is its octave overtone or second, which in this case will be A above middle C, the pitch to which the mouth will resound. Besides this prominent overtone, o has some feeble third and fourth overtones, and for the personal peculiarity say a little fifth. What is
Fig. ”

“ Here he worked for six months, and then went to Stratford, Canada, as night-operator. He soon after went to Adrian, Michigan, where, in addition to his telegraph-office, he had a small shop and tools, to which he turned his hand at odd moments for the purpose of repairing instruments. This situation he lost by violating some rule while absorbed in his workshop, but in two months after appeared in Indianapolis, where he came out with his first invention, an automatic repeater—an arrangement for transferring a message from one wire to another without the aid of an operator. ”

“ He introduced improved apparatus, invented the gold printer, put up a private line, and finally sold it to the Gold and Stock Company, together with his services, or the privilege of having the first option to buy his telegraphic inventions. He was now fully launched on a tide of success. To furnish his instruments, he established a factory in Newark, New Jersey, employing three hundred men. As a manufacturer he was not a success. ”

“ The other, the mouth, as an echo-cave or resonator, no less wonderful in its power of forming itself to resound the harmonics of the vocal tones. This gives the
voice its power of imitating any sound within its reach. We will analyze the voice. ”

“ If these clang-waves were to come along fast enough to blend, and at regular intervals, they would produce a tone of their own. The clanging of the clapper would not be a noise, but a deep tone, perhaps making a chord with the ring-tone. ”

“ Experiments with this "carbon telephone," as it is called, are unfolding every day its marvelous sensitiveness, as shown in its microphonic manifestations, which have been exciting so much wonder. No less successfully is it being brought to measure the pressure caused by infinitesimal heat—for instance, that received by us from the stars. ”