Page:Collier's New Encyclopedia v. 09.djvu/333

LEFT TELEGBAPH 281 TELEGRAPH The leading principle in the ^orse and other allied instruments is that by the depression of a key or other method, an electric circuit is "closed" or completed, and a signal is transmitted along the wire to the distant station, where, on its arrival, it reproduces the signal by the action of an electro-magnet or otherwise. Electrically the Morse consists of a transmitting key and an electro-magnet and armature; while mechanically it con- sists of a lever, with circular wheel or disk attached to the armature, and a clockwork arrangement, by which the pa- per tape to be printed on is carried for- ward under the disk. In the first Morse instruments the marks were made on the paper with a pointed style (the instru- ment being thus known as the "embos- ser"), but by the invention of the ink writer, a form of register now much used in Europe and Asia, the legibility and permanence of the record are secured, be- sides the advantage that a very light cur- rent will serve to make the marks. The instrument most in use in the United States and Canada, as wiell as in India and to some extent in Europe, is the "sounder," which is simply a Morse register stripped of all its parts except the electro-magnet, the lever, and the spring, the operator reading by the click- ing sounds caused by the opening and breaking of the circuit. By this method the message is read and copied simulta- neously, the speed of transmission is greatly increased, and the experience has proven that the proportion of errors is much diminished. The American Morse alphabet, used in the United States and Canada, is as follows: A w B X . C .. . Y D Z E. F. G & 1 2 . H .... 3 . I .. J K L M 4

6 TT.TT.~ 7 8 N 9 O. . . P

Q R. .. C^) S ... (?) T _ ( ') U (" ") V The International Morse alphabet is used in all other parts of the world. The signals, as given below, are arranged in the groups, and accompanied by the mnemonic phrases adopted by the Brit- ish Postoffice when, in 1870, the transfer of the telegraphs to the government ren- dered necessary the rapid training of thousands of operators throughout the kingdom : Group 1. E, Earwigs I, infest ... S, summer .... H, houses. Group 2. — T, Turnips M, make O, oxen Ch, cheerful. Group 3. A, A — W, wet J, jacket's U, uncomfortable. — V, very ! Group 4. N, No D, difficulty B, baffles — G, great — . Z, zeal. Group 5. R, Remember! L, Law — P, preserves F, freedom. Group 6. — K, Kindness — C, conciliates Y, youth — X, extremely Q, Quickly 6, Each figure is represented by five sig- nals, but on busy circuits expert clerks adopt the practice of "sending short," omitting all after the first dash in the figures 1, 2, 3, and 4, and all before the last dash in 7, 8, 9, and 0. It is stated that Professor Morse founded his alpha- bet upon information given him by his brother, a journalist, as to the numerical relation of the letters in the English al- phabet, the simplest signal (a dot) being given to E, and the next simplest (a dash) to T, those letters occurring most frequently in our language. The inter- national alphabet is considered prefer- able, as it contains no spaced letters, which sometimes gives rise to errors in reading. The process of transmitting more than one communication at the same time over the same line, known as the "duplex" method, was first introduced in the United States, and afterward in Europe, by J. B. Stearns, of Massachusetts, who made his first successful experiment in 1852. The "quadruplex" method was invented by Thomas A. Edison in 1874. Subsequent improvements have been made, and the multiple pro- cess, in one form and another, is now extensively used, by means of which the working capacity of the lines is in- creased at least 25 per cent. An auto- matic telegraph, in which the message was transmitted from a strip of paper