Magnetic telegraph

“ I find three or four ordinary laborers to-day putting up the necessary outdoor fixtures for a magnetic telegraph from Boston to Burlington. They carry along a basket full of simple implements, like travelling tinkers, and, with a little rude soldering, and twisting, and straightening of wires, the work is done. It is a work which seems to admit of the greatest latitude of ignorance and bungling, and as if you might set your hired man with the poorest head and hands to building a magnetic telegraph. ”

“ Electro-Magnetic Telegraph. The art of telegraphing by means of galvanism and electro-magnetism is certainly the most interesting application of scientific acquirements ever made to purposes useful to society at large. By means of it, ere long, the inhabitants of the various parts of the globe will be able to correspond with each other, through oceans and seas, to a far greater extent than is probably within the expectation of most people. ”

“ The principle on which, my whole invention rests is the power of the electro-magnet commanded at pleasure at any distance. The application of this power to the telegraph is original with me. If the electro-magnet is now used in Europe for telegraphic purposes, it has been subsequently introduced. All the systems of electric telegraphs in Europe from 1820 to 1840 are based on the deflection of the magnetic needle, while my system, invented in 1832, is based, as I have just observed, on the electro-magnet.... ”

“ Now, there is no person on the face of the globe who can measure the price at which, if a reasonable man, he would be willing to strike from the world the use of the magnetic telegraph as a means of communication between different portions of the same country. ”

“ By means of magnetic telegraph systems, man has established instant communication with all parts of the world. Not the highest mountain ranges, not deserts, not even ocean's wide expanse, have been sufficient to bar his way. He has made the earth a net-work of his cables and telegraph lines, until nearly every part of the earth is within the radius of instant communication. In 1896, the National Electric Light association celebrated the triumphs of electricity by holding a national electrical exposition in New York City. ”

“ It employs an alternating current and four transmitters and receivers can be used in connection with one wire. There is a mechanical keyboard somewhat similar to that of a typewriter, while the signals are received and printed on a tape or upon ordinary letter pages in ‘typewriting’ characters.
In the United States the telegraph is entirely in the hands of private companies. The first company was organized in 1845 under the name of the Magnetic Telegraph Company by Morse's supporters and associates. ”

“ The admirable arrangements made at the Magnetic Telegraph office in Old Broad Street for connecting ten subterranean gutta-percha insulated conductors of over two hundred miles each, so as to give one continuous length of more than two thousand miles, during the hours of the night when the Telegraph is not commercially employed, furnished us the means of conclusively settling by actual experiment the question of the practicability as well as the practicality of telegraphing through our proposed Atlantic cable.... ”

“ Make the magnet so that the diminished current will exercise its full effect. Instead of using one short coil, through which the current can easily slip, and do nothing, make a coil of many turns; that increases the magnetic field: make it of fine wire, and of higher resistance. And then, to prove the truth of his discovery, Henry put up the first electro-magnetic telegraph ever constructed. In the academy at Albany, in 1831, he suspended 1,060 feet of bell-wire, with a battery at one end and one of his magnets at the other; and he made the magnet attract and release its armature. ”

“ The great difficulty in their way was the fact that the galvanic current, however strong in the beginning, became gradually weaker as it advanced on the wire; and was not strong enough to produce a mechanical effect, after a certain distance had been traversed. But, encouraged by the discoveries which were made from time to time, and strong in the belief that an electro-magnetic telegraph was practicable, many eminent and scientific men in Europe, as well as in this country, became deeply engaged in endeavoring to surmount what appeared to be the chief obstacle to its success. ”

“ The primitive telephone has been greatly improved, the double electro-magnet being replaced by a single bar magnet having a small coil or bobbin of fine wire surrounding one pole, in front of which a thin disc of ferrotype is fixed in a circular mouthpiece, and serves as a combined membrane and armature. On speaking into the mouthpiece, the iron diaphragm vibrates with the voice in the magnetic field of the pole, and thereby excites the undulatory currents in the coil, which, after travelling through the wire to the distant place, are received in an identical apparatus. ”

“ 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. ”

“ And so, perforce, as the inevitable consequence of the growth of the telegraph industry, and mainly at the hands of those interested in submarine telegraphy, there came about the system of electrical and electromagnetic units, based on the early magnetic work of Gauss and Weber, developed further by Lord Kelvin, by Bright and Clark, and last but not least by Clerk Maxwell. Had there been no telegraph industry to force electrical measurement and electrical theory to the front, where would Clerk Maxwell's work have been? ”

“ We are in great haste to construct a magnetic telegraph from Maine to Texas; but Maine and Texas, it may be, have nothing important to communicate. Either is in such a predicament as the man who was earnest to be introduced to a distinguished deaf woman, but when he was presented, and one end of her ear trumpet was put into his hand, had nothing to say. As if the main object were to talk fast and not to talk sensibly. We are eager to tunnel under the Atlantic and bring the old world some weeks nearer to the new; ”

“ There are several causes producing currents in a telegraph wire which do not satisfy this limitation. During thunderstorms surgings may arise, at least in overhead wires, without these being actually struck. Again, if the circuit includes a variable magnetic field, electric currents will be produced independently of any direct source of potential difference. In the third circuit at Parc Saint Maur, where no earth plates exist, the current must be mainly due to changes in the earth’s vertical magnetic field, with superposed disturbances due to atmospheric electricity or aerial waves. ”

“ I used six wires forming three metallic circuits and influencing three needles. I worked out every possible permutation and practical combination of the signals given by the three needles, and I thus obtained an alphabet of twenty-six signals. I had invented the instrument which I called the detector; by means of which injuries to the wires, whether from water, fracture, or contact, are readily traced; an instrument which, in practice, is never out of my hand, and without which the electric telegraph would be impracticable. ”

“ There were thus two ways of producing visible motion by means of an324 electric current: that of Oersted’s simple experiment, in which a suspended magnetic needle was deflected by a current, and that made possible by the production, at will, of an electro-magnet. The application of both of these ideas to the construction of an electric telegraph was quickly attempted, and two different systems of telegraphy grew out of them. One, depending on Oersted’s experiment, was developed in England first and afterwards in Europe ”

“ Since that time great improvements have been made until now it is difficult to recognize in the delicate mechanisms of the relay, key, sounder, duplex, quad, and multiplex, the principle first promulgated in the old Morse register. Its influence was at once felt in all walks of life; it was an art to be an expert telegrapher. Keeping pace with the strides of advancing civilization, the telegraph has spread its slender wires, until now almost the entire world is connected by its magnetism. ”

“ The question that addressed itself to him at the outset was, naturally, this: 'How can I make use of the simple up-and-down motion of opening and closing a circuit to write an intelligible message at one end of a wire, and at the same time print it at the other?'... Like many a kindred work of genius it was in nothing more wonderful than in its simplicity.... Not one of the brilliant scientific men who have attached their names to the history of electro-magnetism had brought the means to produce the practical registering telegraph. ”

“ So true it is that on our planet the best intentions are often mixed up with a few grains of folly.
After steam, the electric light and the telegraph and the telephone, the discovery of unmistakable signs of the existence of humanity inhabiting another region of our solar archipelago, would that not be the most marvellous apotheosis of the scientific glory of the twentieth century? And cannot wireless telegraphy be some day applied to this problem? Electro-magnetism is an immense invisible world still insufficiently explored. ”

“ The reason why oscillations have no effect in a telephone is no doubt because they change so rapidly, at rates, as has been mentioned already, of the order of a million per second. The telephone diaphragm, [Pg 260] light and delicate though it is, is far too gross and heavy to respond to such rapidly changing impulses as that. In the magnetic detector the difficulty is overcome by making them change the magnetic condition of some iron wire which change in turn produces currents capable of operating a telephone. ”

“ Secondly, if the metallic powder placed in the cavity is a magnetic metal, the receiver will be somewhat less sensitive, but will work with more precision, because of the magnetic action of the magnet of the telephone upon the cohering powder. If no recording apparatus is used, the observer must write down the signals as heard in the telephone, since corresponding to a short spark at the transmitting station, a single tick or short sound is heard at the telephone, and corresponding to a series of rapidly successive sparks, a more prolonged sound is heard in the telephone. ”

“ The same principle holds good in wireless telegraphy. If we wish to communicate to a great distance the ether must be disturbed in proportion to the distance. The vibrations that produce light are not sufficient in intensity to affect the ether in such a way that signals can be carried to a distance. Other disturbances, however, can be made in the ether, stronger than those which create light. If we charge a wire with an electric current and place a magnetic needle near it we find it moves the needle from one position to another. ”

“ In 1833 the celebrated scientists, Gauss and Weber, placed a line of wire from the Observatory of Göttingen University to a building a mile distant, and by sending magneto-electric currents through that wire they communicated intelligible signals; but as the needle they used weighed nearly a hundredweight they saw that their apparatus needed much improvement before it would be of practical utility. Being otherwise engaged themselves, they invited Professor Steinheil, of Munich, to construct an improved electric telegraph ”

“ The effect of this is that the magnet in the receiver of the other telephone is receiving a rapidly changing current, which, producing corresponding magnetic changes, makes the magnet alternately weaker or stronger. This influences, by magnetism, the iron diaphragm accordingly, and makes it reproduce the same vibrations that were caused by the speech at the transmitter of the sending telephone. ”

“ While in the ordinary wireless instruments the discharge surges back and forth between the antenna and the earth, in the flying-machine wireless the discharge surges back and forth between the two antennæ. In the Wright machine, when equipped for wireless telegraphy, the two antennæ are placed one under the upper plane, the other under the lower plane of the flying-machine. [221]
More power is required for the wireless than for the wire telegraph. In the wire telegraph about one-hundredth horse-power is required to send a message one hundred and twenty miles. ”

“ Others had followed in his footsteps, using the musical telephone to transmit messages with the Morse code by means of long and short hums. Elisha Gray, of Chicago, also experimented with the musical telegraph. At the transmitting end a vibrating steel tongue served to interrupt the electric current which passed over the wire in waves, and, passing through the coils of an electro-magnet at the receiving end, caused another strip of steel located near the magnet to vibrate and so produce a tone which varied with the current. ”

“ Telegraphy is the process of transmitting messages from place to place by means of an electric current. The principle underlying the action of the telegraph is the principle upon which the electric bell operates; [323] namely, that a piece of soft iron becomes a magnet while a current flows around it, but loses its magnetism as soon as the current ceases.
In the electric bell, the electromagnet, clapper, push button, and battery are relatively near,—usually all are located in the same building ”