Page:The New International Encyclopædia 1st ed. v. 19.djvu/116

From Wikisource
Jump to navigation Jump to search
This page has been proofread, but needs to be validated.
TELAUTOGRAPH.
90
TELEGRAPH.

strength upon the position of the pencil on its writing surface. At the receiver are two strong electro-magnets, each one having one of its poles inclosed by the other, forming two annular spaces, across which the magnetic fields are uniform and constant. In these annular spaces are suspended two light coils of copper wire attached to bell-crank devices and light rods to a set of shafts and levers, similar to those at the transmitter. The pull of each magnetic field upon these suspended coils is opposed by a retractile spring, and the pen at the receiver is thus caused to take a position in its writing field exactly corresponding to that of the transmitter pencil. The switching on of the transmitter by means of a switch at the transmitter end automatically brings fresh paper to the writing surface from a roll beneath the transmitter, throws the receiver at the distant end into operating position, shifting its paper and raising the pen from the ink-well ready to write. When the transmitter is switched off no current is consumed at either end. A small switch placed beneath the writing surface at the transmitter is opened and closed by the pressure of the pencil thereon, and serves to control by means of induced vibratory currents and a suitable relay, the receiving pen, causing it to be raised from the paper or lowered to it, in unison with the movements of the transmitting pencil. The ink is automatically supplied to the receiver pen, and when not in use the pen rests with its tip immersed in the ink, and thus is always ready for service. The writing field is 2 inches by 5 inches, thus affording space for three lines of ordinary writing, each 5 inches long. Upon this field the writing is done and when filled a simple movement of the switch at the transmitter brings fresh paper into service at both ends of the line. A small push button serves to operate a call bell, by which all signaling is done.

TELAUTOGRAPH WITH CASE REMOVED SHOWING MECHANISM.

The instrument is used by the United States Army in transmitting messages from the range-finding stations in the coast defenses to the high-power guns, telephones having been found unsatisfactory for this service, because disabled by the unavoidable shock. In commercial work the telautograph can be conveniently employed, as it makes a double record of each message, one for the sender and one for the person addressed.

TELAV, tyĕ-lȧf′. A district town in the Government of Tiflis, Russian Transcaucasia, 63 miles east-northeast of Tiflis (Map: Russia, G 6). It was formerly the capital of Kachetia and has ruins of old palaces. Population, in 1897, 11,810, chiefly Armenians and Georgians.

TELEDU. See Badger.

TELEG′ONUS (Lat., from Gk. Τηλέγονος). The son of Odysseus by Circe. Having been sent to Ithaca to find his father, he failed to recognize him in combat and slew him, afterwards taking the body home, together with Telemachus and Penelope, whom he married. He was looked upon as the founder of Tusculum and Præneste, and, through his daughter Mamilia, as the ancestor of the Roman Mamilii. His story is the theme of the Telegonia. See Trojan War.

TELEGONY (from Gk. τῆλε, tēle, afar + -γονία, -gonia, generation, from γόνος, gonos, seed, from γίγνεσθαι, gignesthai, to become, to be born). The influence of the first or of a previous sire on the subsequent progeny obtained by other sires. That the first impregnation has a lasting influence has been generally accepted by breeders. Weismann, however, states that the most competent judges in Germany, such as Stettegast, Nathusius, and Kühn, in spite of their extensive experience in breeding and crossing, have never known a case of telegony, and doubt its reality.

TELEGRAPH (from Gk. τῆλε, tēle, afar + γράφειν, graphein, to write). The transmission of messages by means of electricity. With the discovery that electric currents could be transmitted instantly over long distances came the idea of employing them for signaling, and in 1774 Bishop Watson made some experiments in discharging Leyden jars through 10,000 feet of wire, suspended on wooden poles, in the neighborhood of London. In the Scots Magazine in 1753 a detailed description of a plan for electric telegraphy is given, and in 1774 a telegraphic line was erected by Lesage at Geneva, Switzerland, which consisted of twenty-four wires connected to pith-ball electroscopes (q.v.). each representing a letter. When the connection between the frictional machine or charged conductor and any electroscope was made the pith-ball was repelled. The difficulty of using frictional machines, the only method for producing electricity then known, however, prevented the attainment of any practical results in this direction before the discovery of the voltaic cell. In Germany the invention of the telegraph is credited to Sömmering of Munich, whose original apparatus, constructed about 1809, was exhibited in operation at the Congress of Electricians at Frankfort in 1891. This instrument consisted of a series of voltameters each corresponding to a certain letter or signal. On closing the key in any circuit the signal was transmitted to the corresponding voltameters and the water in the appropriate tube was decomposed. A similar plan was proposed about the same time by Dr. J. R. Coxe, of Philadelphia. Immediately after the discovery