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Fig. 3. The olphobet of Revised Morse; the code used in telegraphy throughout Americo ond Con-ada.

arms moved. Movement of the three members produced a large number of configurations which a viewer at the next tower read through a telescope. When in ]852 the electric telegraph replaced the semaphore system, a network of 556 semaphore stations covered France stretching over a total distance of 3000 miles.

England used a different scheme. The visual system installed by the British Admiralty between London and its naval bases consisted of 15 towers each supporting a horizontal board that contained six circular holes opened and closed by shutters. A round-trip test run over the London to Plymouth circuit covered the 500-mile route in three ininutes-170 miles a minute. A tremendous speed at that time, but a speed dependent upon daylight and clear weather. In the United States, the first semaphore system connected Martha's Vineyard with Boston in 1800.

For speed and maximum intelligence, inventors turned to alphabetic codes. Fig. 1 shows a comparison of nine. Probably the first five-unit, even-letter code of record appears in Francis Bacon's monumental work, "Advancement in Learning" published in 1605. It antedates Morse by over 200 years. Bacon's code used two letters; "a" and "b". By juggling them around through five positions, he obtained thirty-two differences—far more than the twenty-four required for the alphabet then used. (J and U didn't appear in the alphabet at that time)

In volume eight of Dr. Abraham Rees' Cyclopedia published in 1809, a signaling alphabet similar to Bacon's appeared using numbers instead of letters. This code included symbols for letters "J" and "U". The first nine letters ol the alphabet followed exactly the notation of Bacon. After injection of the letter "J" which takes the same symbol as Bacon s "K", the remainder of the alphabet from * to "V" in clusive follows regularly the arrangement of Bacon's but shifted two letters downward. Only the symbols for "X", and "Y", and "Z" differ. See columns I and II of Fig. L

James Swain of Philadelphia in JS2U published he Mural Diagraph. or the Art of Conversing through a W all" Sometimes designated the prison code, the symbol signifies an audible tap or knock, and the "s" an audible scratch. Swain failed to use the simplest combinations of taps and scratches possible. He gave five signals to "N" "R", "T'\ and "W" and six to "X" when combinations of only four could suffice to make characters. Also, bvt adopting the "numeral system," Swain could not escape using awkward, spaced letters n two-thirds of the alphabet. Column III shows this code.

Baron Schilling of Cronstadt, a Russian counselor of state, used the low potential cell of Alessandio Yolta and the galvanometer of Luigi Galvani to develop a telegraph system moving an upright pointer to the left or right of a fixed position. His code consisted of combinations of (he letters "R" (right) and "L" (left) as shown in column IV. Five letters of Schillings code appear in the International Morse code.

Gauss and Weber of Germany introduced a telegraph system in 1833 that used an V and *T code of unequal length, A simple plus or minus dot made up the binary combinations; Steinheil expanded upon their system. He also used the V' and method but his equipment made dots upon a ribbon of paper from small becks holding ink. Two rows of dots appeared, one lo the left and one to the right, looking very similar to a modem cable signal record. Like Schilling and Gauss, Steinheil gave short mbnls to the letters appearing most often in German. In a paper published in Sturgeons ill 1839, he anticipated reading telegraphy by ear.

American Morse

Professor Samuel Fin ley Breeze Morse solved the telegraph problem by not expecting too much out of a primary circuit. His first apparatus, however, bore little resemblance to the final system put into operation between Washington and Baltimore May 24, 1844- Neither did the code.

Morses patent disclosure dated October 3, 1837, showed a pendulum holding a pencil in contact with a moving strip of paper. A continuous line appeared on the paper. Pieces of cast type containing 1 to 9 raised points, (equal to the numbers they represented) fit into a hod 1er when composed to form a mes-

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