Tekeli's followers. But Tekeli would not trust the emperor and refused to disarm. He was supported by the Turks, who crowned him king of upper Hungary, and he took part in the famous raid of Kara Mustapha into Austria. Soon many of his partisans deserted him, and his friends, the Turks, imprisoned him, but again in 1690 he was at the head of a Turkish force with which he burst into Transylvania, routed the Austrians and roused the Hungarians to renewed efforts for freedom. But several Austrian victories over the Turks forced them to sign a treaty agreeing no longer to support the Hungarian rebels. As a result, Count Tekeli was driven from the country for whose deliverance he had risked everything, and died at Constantinoplep in 1705. His wife was a noted beauty, but more noted for her gallant defense of her castle against an army of Austrians.
Telau′tograph, an ingenious instrument invented by Elisha Gray, for reproducing autograph-writing, messages, drawings and sketches in facsimile and transmitting such to places distant many miles apart by means of an electric motor driven by a local battery. The message, at the receiving point, is written on the sketch drawn by pencil on a roll of paper drawn over drums, and so arranged that they can be shipped forward by the operator at intervals, as each line of writing or drawing is finished. The receiving-pen, which is a small glass-tube furnished with writing-fluid by capillary attraction, being controlled by the current-impulses from the transmitting pencil, it follows and reproduces all its movements, which are then electrically transmitted.
Tel′egraph, an instrument for transmitting signals to a distance. Unless otherwise specified the word is generally used to mean the electric telegraph, which is the only one we shall here discuss.
Electric signals appear to have been first transmitted on a commercial scale by Wheatstone and Cooke in England in 1837. At each end of the “line,” which consisted of five insulated metallic wires, they placed five galvanometers. Different combinations of deflections to the right and left indicated different letters. (See Galvanometer.) Later a single galvanometer was used, different combinations of deflections indicating as before different letters. About the same time S. F. B. Morse (q. v.) in America succeeded in perfecting a receiver in which the signals could not only be seen and heard, but were automatically recorded. This is the instrument which was in universal use in the United States until operators learned to read the message by the click of the instrument. Accordingly, for ordinary work a telegraph line is provided at each end with a battery for producing an electric current, a key for opening and closing the circuit and a small electromagnet, with pivoted armature, the so-called sounder or receiver. More recently the Wheatstone bridge has been applied to the telegraph line in such a way that two messages may be sent over a line in opposite directions at the same time. This is called the duplex telegraph. Edison has invented a method for sending two messages over the same line in the same direction at the same time. This is known as the diplex telegraph. By combining these two, four simultaneous messages may be sent. This system is called the quadruplex telegraph. Various plans have been suggested for sending even more than four messages at once. This is called the multiplex telegraph. Rowland (q. v.) perfected a system which will not only transmit six or eight simultaneous messages, but will deliver them printed on a typewriter; and not only so, but the sending instrument of the Rowland telegraph is merely the ordinary keyboard of a typewriter. For details concerning these various systems and concerning the important subject of submarine telegraph, first worked out by Lord Kelvin, the student is referred to the larger treatises.
Teleg′raphy, Wireless, consists in sending and receiving electrical signals between places without the use of connecting wires.
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Fig. I. (I) induction coil; (G) spark gap; (K) battery key; (A) vertical wire; (E) ground. |
