Figure 23. — Principle of Wheatstone and 

 Cooke's "step-by-step" dial telegraph. From 

 R. Sabine, History and Progress of the Electric 

 Telegraph, London, 1872, p. 177. 



electromagnet. The relative simplicity and rugged- 

 ness of the Morse system made it the most successful 

 one in 19th-century America and, indeed, in the 

 greater portion of the world outside the British Empire. 



Morse apparently started thinking about an elec- 

 trical telegraph upon his return from France in 1832, 

 as the result of some conversations on board ship. 

 A copy of Morse's notebook dealing with the subject 

 of these conversations is preserved in the Museum 

 of History and Technology of the Smithsonian In- 

 stitution. The copy includes a sketch of what appears 

 to be an electrochemical receiver similar to Dyar's 

 and another sketch in which an electromagnet 

 actuates an armature to move a style against a roll 

 of paper (fig. 29). However, Morse's ignorance of 

 electricity and his need to make a living prevented 

 him from building a working model of his telegraph 

 for several years. 



In November 1835 Morse obtained a position at 

 New York University as professor of arts and design. 

 Since his duties there left him some free time, he 

 began to reduce his ideas on telegraphy to practice. 

 By the end of that year he had worked out a trans- 

 mitter and an electromagnetic receiver. This device 

 was literally a telegraph — an instrument for writing 

 at a distance. Type was set up in a port rule or 

 composing stick (fig. 30, top), which was then cranked 

 through a device that opened and closed the circuit 

 according to the hills and valleys on the type. At 

 the other end of the line, this opening and closing of 

 the circuit caused a wooden pendulum, suspended on 

 an old canvas-stretcher, to swing back and forth, 

 and, in so doing, to make zig-zag marks on paper tape 

 (fig. 30, bottom). However, further progress was 

 halted by the usual problem of telegraph inventors — 



Figure 24. — Wheatstone and Cooke's "step- 

 by-step" receiver (top) and transmitter of 1840. 

 From E. Feyerabend, Der Telegraph von Gauss 

 iind Weber. Berlin, 1933, p. 78. 



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



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