Telegraph wire

“ Frequently the disturbances were so loud in the telephone as to destroy conversation. When a second telephone line was strung alongside the first, even though perfectly insulated, another surprise awaited the telephone pioneers. Conversation carried on over one of these wires could plainly be heard on the other. Another strange thing was discovered. Iron wire was not so good a conductor for the telephone current as it was for the telegraph current. ”

“ The aerial wire is precisely the same for either wireless telegraphy or wireless telephony. The transmitter of a wireless telegraph set generally uses a spark gap for setting up the electric oscillations, while usually for wireless telephony a vacuum tube is employed for this purpose. The receptor for wireless telegraphy and telephony is the same and may include either a crystal detector or a vacuum tube detector, as will be explained presently. ”

“ A twisted cable of telephone wire may, when each circuit is formed by diametrically opposite wires, be placed in the same tube with similar cables employed for telegraph purposes. The central wire of the cable may be used either as a telegraph line or as a telephone line having an earth return. Another method is to use powerful telephone transmitters and insensitive receivers ; that is to say, make the telephone currents so powerful that the telegraphic induced currents will be small in comparison, and use receivers so insensitive as to suit such currents. ”

“ 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. ”

“ My purpose was to first tap the wires and attach my pocket instrument and have some fun out of it. Another reason for disappointment was, that I had discovered—if not patented—a safer and surer method of destroying telegraph lines. Of course a mile of wire is more easily transported then a mile of rails. Two men can carry a half-mile coil of wire. A telegraph line can be rebuilt and used with the wire lying on trees, or even fences, in dry weather. ”

“ 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{813} current, and is easily overpowered by the action of a stronger current in any wire near which the telephone wire may come. ”

“ At times when there is no need of hurrying matter forward on the wires, the rapid system can be cut out through shifting a plug. The wires are then used in the ordinary way, sending messages directly by the key. As a result it is considered that the system is one of value principally to telegraph companies or those using leased wires. The general public, however, will benefit through the prompter sending of messages and doing away with the delay so often experienced when there are wire troubles and capacity is reduced below normal. ”

“ One such wire will care for all the business of many long-distance trunks. The public also absorbs the telegraph product of telephone lines. Such telegraph service is leased to brokers, manufacturers, merchants, and newspapers. Railway companies use portable telephone adjuncts to telegraph circuits on trains for service from stations not able to support telegraph attendants, and in a limited degree for the dispatching of trains. Telephone train dispatching, however, merits better equipment than a railway composite system affords. ”

“ The signals by which messages are received and read by the ear are produced by a bar of soft iron striking upon a steel point placed between two coils of wire. With the A.B.C., double-plate sounder, and sounder, only one message can be sent or received on the wire at one time; but the duplex sounder instruments are so constructed that two messages can be sent on the wire—one in each direction—at the same time. Double-current duplex instruments are in use for telegraphing to busy towns such as Plymouth, Exeter, Cardiff, Swansea, &c., &c. The quadruplex consists of two duplex sets upon one wire. ”

“ CARBON-DUST TRANSMITTER
The strength of current required for the telephone is very small. To transmit a telephone message requires less than a hundred-millionth part of the current required for a telegraphic message. The work done in lifting the telephone receiver a distance of one foot, if changed into an alternating current, would be sufficient to keep up a sound in the receiver for a hundred thousand years. Because of its extreme sensitiveness the telephone requires a complete wire circuit. The earth cannot be used for the return circuit, as in the case of the telegraph. ”

“ Hence his name in England has been most prominently associated with the invention of the electric telegraph. Many able men had tried to solve the problem before him, but had not succeeded. Yet that which our wisest forefathers regarded as chimerical, and scientists of different nations laboured for in vain, we are now told was so obvious and simple as scarcely to deserve the name of an invention.
The electric telegraph claims a long pedigree. One of the first attempts to transmit signals through a wire by means of electricity was made in 1727 by Stephen Gray, a pensioner of the Charterhouse. ”

“ Thus by 1832 the electric current had been used for sending signals at a distance and the electric telegraph had been invented.
But the electric telegraph was still only a toy. How could it be made a practical machine? How could it be used for sending messages in a satisfactory manner? Inventors everywhere worked diligently to discover a satisfactory method of signaling and many ingenious systems were invented. As early as 1837 a telegraph line was established between Paddington, England and Drayton—a distance of 13 miles—and messages were sent over the wire. ”

“ The transmitter as a rule consists of a mechanically or motor driven mechanism which causes the telegraph impulses to be transmitted to the line, and the combination and character of the impulses are determined by the tape perforations. The rapidity with which the tape may be driven through the transmitter makes very high speed operation possible. Of course it is necessary that there should be at the other end of the wire apparatus capable of receiving and recording the signals as speedily as they are sent. ”

“ Wherever a telephone circuit has been made upon telegraph poles having other wires upon them, the inductive actions of the currents upon the other wires has been found to seriously interfere with the action of the telephones, inasmuch as the latter reproduce every other message. One skilled in reading by sound in the ordinary way can read through the telephone what message is travelling in a neighboring wire. ”

“ In this apparatus a vibrating steel tongue interrupted the current, which at the other end of the line passed through the electro-magnet and vibrated a band or tongue of iron near its poles. Gray's 'harmonic telegraph,' with the vibrating tongues or reeds, was afterwards introduced on the lines of the Western Union Telegraph Company in America. As more than one set of vibrations—that is to say, more than one note—can be sent over the same wire simultaneously, it is utilised as a 'multiplex' or many-ply telegraph, conveying several messages through the same wire at once ”

“ The invention used in sending messages in that way is one which enables a man in New York, by touching keys like those of a piano, to operate a printing-machine in Boston or Chicago.
The highest achievements in telegraphy are undoubtedly reached in the ocean telegraph. It demanded a whole line of inventions peculiar to itself. A simple wire could not be used for a conductor. It would give out the electricity to the water so fast that none would reach the farther end to deliver the message, and the wire itself would be speedily destroyed. ”

“ 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. ”

“ It is by improving the coverings which prevent the current escaping from its wire, by taking advantage of the fact that a wire can almost as well carry a current of high tension as of low, and, above all, by increasing the quantity of the current so as to make the enterprise worth while, that the telegraphy of power has followed upon the telegraphy of mere signals.
In the telegraph at work over long distances a remarkable peculiarity of electricity displays itself. ”

“ The lines of electric telegraph are increasing so rapidly, that the length in actual use cannot be estimated at any moment with accuracy. At the commencement of 1848, it was stated that the length in operation in this country was about 3000 miles. At the end of 1850, the lines in operation, or in progress, in the United States, amounted to 22,000. In 1853, the total number of miles of wire in America amounted to 26,375.
It is but fifteen years since the first line of electric telegraph was constructed in this country ”

“ The apparatus B, a sonorous box on the cover of which is placed the wire-spiral with the steel axis, wich will be magnetic when the current goes through the spiral. A second little box is fixed on the first one, and laid down on the steel axis to increase the intensity of the reproduced sounds. On the small side of the lower box you will find the correspondent part of the complementary telegraph.
“If a person sing at the station A, in the tube (x) the vibrations of air will pass into the box and move the membrane above ”

“ The weights of material used in this cable are: copper wire, 495 tons; gutta-percha, 315 tons; jute yarn, 575 tons; steel wire, 3,000 tons; compound and tar, 1,075 tons; total, 5,460 tons. The telegraph-ship Faraday, specially designed for cable-laying, accomplished the work without mishap.
Electrical science owes much to the Atlantic cables, in particular to the first of them. At the very beginning it banished the idea that electricity as it passes through metallic conductors has anything like its velocity through free space. ”

“ As the waves shoot out and reach the distant station, the filings in the tube cohere and the current passing through them draws up the armature of the relay magnet. This closes the circuit of the recording instrument. It is broken constantly [156] by the tapper and instantly re-established by receiving waves.
The towers employed in 1920 for the transmission of wireless messages were very high. The manifest advantages of the system were apparent and long before 1930 wireless telegraphy came into general use. The new system proved the death-knell of telegraph poles, as well as ocean cables. ”

“ The idea of replacing a galvanometer, which was preferably a well-damped or speaking galvanometer, by a relay working an ordinary sounder or Morse was an obvious one, but so far as the present author was concerned he did not realise that there would be any particular practical advantage in thus with difficulty telegraphing across space instead of with ease by the highly developed and simple telegraphic and telephonic methods rendered possible by the use of a connecting wire. In this non-perception of the practical uses of wireless telegraphy he undoubtedly erred. ”

“ Discovery may need to intervene, to enable invention to restimulate.
In both telegraphy and telephony, the longer the line the weaker the current which is received at the distant end. In both telegraphy and telephony, there is a length of line with a given kind and size of wire and method of construction over which it is just possible to send intelligible speech or intelligible signals. A repeater, in telegraphy, is a device in the form of a relay which is adapted to receive these highly attenuated signal impulses and to re-transmit them with fresh power over a new length of line. ”

“ As a result of exhaustive researches, too extensive to describe here, it has been ascertained that the function of the wireless telephone is not to do away with the use of wires, but rather to be employed in situations where wires are not available or practicable, such as between ship and ship, and ship and shore, and across large bodies of water. The ether is a universal conductor for wireless telephone and telegraph impulses and must be used in common by all who wish to employ those agencies of communication. ”

“ "SIRE, a fresh dispatch."
"Whence?"
"From Tomsk?"
"Is the wire cut beyond that city?"
"Yes, sire, since yesterday."
"Telegraph hourly to Tomsk, General, and keep me informed of all that occurs." ”