believing it to be a reproduction of Gauss' telegraph, 

 and returned to England in April with the intention of 

 transforming his model from a piece of lecture dem- 

 onstration apparatus into a commercial instrument. 



After spending the summer of 1836 working on the 

 needle telegraph, as well as on an unsuccessful syn- 

 chronous telegraph discussed below, Cooke interested 

 the Liverpool and Manchester railroad in trying his 

 needle telegraph for communications through a rail- 

 road tunnel at Liverpool. However, Cooke soon dis- 

 covered that his instrument, while it would work in 

 the space of a laboratory, would not work over a mile- 

 long line. 



Since Cooke was neither a professional scientist 

 nor an instrument-maker, he sought technical as- 

 sistance from several prominent men, including 

 Michael Faraday. Finally, in February 1837, he 

 met Charles Wheatstone,'^ who was professor of 

 experimental physics at King's College, London. 

 Several years previous to the time Cooke met him, 

 Wheatstone, with the ultimate intention of devising 

 an electrical telegraph, had been investigating the 

 distant transmission of electrical forces. In 1834 

 Wheatstone had been successful in sending signals 

 through a reel of wire several miles long and was con- 

 vinced that this newly discovered physical force was 

 capable of being used for communication. In June 

 1836 Wheatstone had proposed a needle telegraph, the 

 essential part of which used what he called a "permu- 

 tating keyboard" that could send 30 different signals 

 over six wires. However, Wheatstone had run into 

 the same difficulty as Cooke had — that of transmitting 

 signals over a long line — and the two men decided to 

 tackle their problems together. Wheatstone and 

 Cooke added to their system a sensitive relay that 

 needed to move only jio inch in order to actuate an 

 alarm, but the main problem of transmitting signals 

 to a distance remained unsolved. 



During a trip to Europe in 1837 Joseph Henry had 

 visited a number of laboratories, that of Wheatstone, 

 among others. Among the topics Henry discussed 

 during a visit to Wheatstone's laboratory were the 

 different properties of quantity and intensity electro- 

 magnets, and of how an intensity electromagnet and 

 battery on a very long circuit had been used at Prince- 



FiGURE 17. — Muncke's 3-needle copy of 

 Schilling's telegraph. From T. Karass, Ge- 

 schichte der Telegraphic, Braunschweig, igog, 

 p. 136. 



ton to actuate a quantity electroniagnet and battery 

 on a local circuit. Possibly as a result of such a dis- 

 cussion, within a few weeks following Henry's visit to 

 their laboratory Wheatstone and Cooke solved their 

 difficulties in the transmission of telegraph signals over 

 long distances. In May 1837 they applied for a patent 

 on their 5-needle invention, which included a call 

 alarm based on a relay and local circuit (figs. 18, 19, 

 22). This British patent (7390) was obtained on June 

 12, 1837. The transmitter of the Wheatstone-Cooke 

 telegraph ^° was a set of five tapper keys that acted as 

 switches. The various keys could indicate the various 

 letters by moving different combinations of needles to 

 left and right positions. 



Wheatstone and Cooke's instruinents were tested with 

 some success in July 1837 on a 1.4-mile line that ran 

 along the London and Birmingham railway between 

 Euston Square and Camden Town. The 5-wire line 

 was mounted on blocks of wood, and the whole was 

 covered with tar and buried in the ,ground along the 

 railroad tracks. However, mechanical difficulties, the 

 expense of installation, and the problem of proper 



" Proceedings of the Royal Society of London, 1876, vol. 24, pp. 

 xvi— xxvii (obituary); Minutes of Proceedings of the Institution 

 of Civil Engineers, 1876, vol. 47, pp. 283-297 (obituary); 

 Magazine of Popular Science and Journal of the Useful Arts, 1837, 

 vol. 3, p. 110. 



20 "Wheatstone and Cooke's Electric Telegraph," Mechanics' 

 Magazine, London, August 1, 1840, vol. 33, pp. 161-170; 

 W. H. Preece, "Communication," Journal of the Institution of 

 Electrical Engineers, 1897, vol. 26, pp. 633-635. 



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