Telegraph

The Horse Alphabet.—Before going further, the details of this alphabet, universally recognized as a masterpiece of cryptography, may be given. The signals, as given below, are arranged in the groups, and accompanied by the mnemonic phrases, adopted by the British post-office when, in 1870, the transfer of the telegraphs to the government rendered necessary the rapid training of thousands of telegraphists throughout the kingdom: Group I. Group 2.

E, Earwigs T, Turnips .. I, infest — — M, make , .

. . . S, summer — — — 0, oxen .

.... H, houses. — — — — Ch, cheerful.

Group 3. Group 4.

• — A, A — • N, No • — — W, wet — • • D, difficulty • — — — J, jacket's — • • • B, baffles • • — U, uncomfortable, — — • G, great • • • — V, very! — — • • Z, zeal.

Group 5. Group 6.

• — • R, Remember! — • — K, Kindness • — • • L, law — • — • C, conciliates • — — • P, preserves — • — — Y, youth • • — • F, freedom. — • • — X, extremely • . Q, quickly.

The arrangement for the numerals is equally ingenious. Each figure is represented by five signals, thus: 1, • — — 2, • • — — — . • • 3, • • • — — . .

9, • 5, 0, These are the numerals printed long, but on busy circuits expert clerks adopt the prac tice of "sending short," omitting all after the first dash in 1, 2, and 3, four of the dots in 5, and all before the last dash in'7, 8, 9, and O. It is stated that prof. Morse founded his alphabet upon information given him by his brother, a journalist, as to the numerical relation of the letters in the English alphabet, 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 Transmitting Key.—The " key" or hammer by which signals are transmitted from the operator at the sending office, is shown in fig. 2, in one of its earliest and most simple forms. The lever 1, 1 turns on its axis A, and has on its under side two platinum nipples, m and 71. L is the line-wire, connected with the axis; E, the " earth"-wire (passing through the Morse on its way to earth, and producing its signal there); and C, a wire con necting the stud a with the battery. As the key stands in the figure, it is in the position to receive a current from the distant station, the course of the current being L, A, 1, n, b, and thence to the electromagnet of the Morse en route to earth. When it is desired to send a current, the handle H is depressed, and the

current, generated in the battery, then comes by the wire C, and passing through a, sta, and A, proceeds by the line-wire to the distant station. Various modifications of this key are in existence, but in all the principle remains the same, that the electric circuit is closed or completed by the depression of the key. The length of time during which the handle is depressed determines the length of the mark produced at the other end. Thus, if the clerk presses down the handle while he says "one—one two three," the inky diskat the other end gives the mark . — (dot dash) or the letter A, and so on through the various letters of the alphabet.

The Battery.—For the generation of power in the electric telegraph, i)aniell's bat teries (see GALVANISM) are chiefly employed in this country. Various forms of the Bun sen battery are also used, especially on the continent. The power employed varies with the length of line, the condition of the wires as regards insulation, and the nature of the instruments used.

The Ctrettit.—The mode of joining up two stations by means of earth-wires, batteries, instruments, and line-wires, is shown in fig. 3. Assuming S and S 1 to be telegraph stations, P and P 1 are the " earth"-plates (see subsequent paragraph), B and B 1 the batteries, n and 72 I the electromagnets and armatures, and b, k, g the transmitting keys and galvanometers. L, L show the line-wire, supported on poles and insulated. The key at station S is shown depressed, so that a current of electricity may be sup posed to be passing from the battery B through the key and galvanometer along the line-wire, and thence through k 1 and n 1 to the earth-plate P 1. Supposing, then, that the clerk at S desires to send a message to S 1, he depresses the key k several times so as to send a series of dots and dashes corresponding to the name (or rather the code signal representing the name) of the distant station. The attention of the clerk being gained by the clicking of the Morse, he turns the switch to set his paper tape in motion, gives the signal that he is ready, and the message is then sent.