Figure 2 1 . — Front and rear views of Wheatstone and Cooke's single-needle 

 telegraph, 1845. Note trough battery. From T. Shaflfner, The Telegraph 

 Manual, New York, 1859, pp. 222, 225. 



Like Davy, Bain also revived the idea of an electro- 

 chemical telegraph. ^5 Bain originally used an 

 ordinary Morse key to open and close the circuit 

 at the transmitting end of the line. Chemically 

 treated paper at the receiving end of the line recorded 

 the action of the transmitter as dots and dashes. 

 However, Bain's first application for a patent was 

 not granted because of conflict with the Morse 

 system. Bain then replaced the Morse key by an 

 automatic one using punched paper. One machine 

 prepared a paper tape by punching broad dots in 

 two parallel rows in it, the various combinations of 

 dots representing different letters. This tape was then 



25 Alexander Bain, British patent 11480 (December 12, 1846); 

 "Mr. Bain's New System of Electro-Telegraphic Communica- 

 tion," Mechanics' Magazine, London, June 19, 1847, vol. 46, 

 pp. 590-592. 



passed between two styli and a metal roller, thereby 

 opening and closing a circuit. The signals thus 

 produced were recorded electrochemically at the 

 receiving end as two similar rows of marks on 

 another paper tape (fig. 26). The Bain system was 

 widely used for a time, for it was capable of high- 

 speed transmission. In 1850 it was used on a 187- 

 mile line from London to Liverpool via Manchester. 

 There were also about 1,200 miles of telegraph lines 

 using this system in the United States in the same 

 period (see fig. 27). However, defects in the crude 

 machinery used in this system and interference on 

 its lines produced spurious signals, and these faults 

 eventually led to the replacement of the Bain 

 telegraph by more efficient automatic signaling 

 devices. 



PAPER 29: DEVELOPMENT OF ELECTRICAL TECHNOLOGY IN THE 19TH CENTURY: II 



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