King's College London
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Imperial designs: technology and empire in the 19th century

Wheatstone's telegraph

Illustration of two-needle and single-needle telegraphs. The five single-needles each bear the name of a railway station below each needle.The electric telegraph used on the Yarmouth and Norwich Railway, when opened as a 'single way,' 1st May 1844.This book documents the struggle between the two inventors of one of the first commercial telegraphs. The King’s physicist Sir Charles Wheatstone (1802-75) was an extremely fecund inventor with a thorough understanding of the science of electromagnetism. Sir William Fothergill Cooke (1806-79) was neither a scientist nor an engineer, but had business acumen, which Wheatstone lacked.

The underlying cause of their mutual suspicion was not a quarrel over patent royalties or profits (which are the subjects of the book shown here) but an argument over the nature of science. The word ‘scientist’ first arose in the late 1830s at the time when Cooke and Wheatstone were becoming acquainted. Wheatstone was undoubtedly a scientist in an age when science was becoming professionalised, and he did not regard Cooke as one.

Wheatstone understood the implications of the newly discovered Ohm’s law of electromagnetism (that current strength is equal to the exciting force divided by a constant designated ‘resistance’) for long-distance telegraphy. He was therefore able to increase the effectiveness of his telegraph by winding the coil surrounding the magnetised needle on a ferromagnetic core. He made the crucial leap which enabled telegraphy to change from a technology of display and amusement to one of practical use.

Illustration depicting needle positions with corresponding letters of the alphabet.Alphabet of the single-needle telegraph.Cooke foresaw the mutual dependence of the railway and the telegraph; the railway would provide the telegraph with protected land and the telegraph would provide the railway with signalling opportunities, which would enhance safety. As a former army officer, he envisaged the utility of the telegraph to the state in countering both criminality and the then endemic political and social unrest. Both these fears had engendered the creation of the uniformed police force in 1829.

The celebrated arrest of John Tavell in 1841 advertised the usefulness of the telegraph. After having murdered his girlfriend in Slough, he boarded a train bound for Paddington. A full description was telegraphed to Paddington.

As the illustration of the telegraph keyboard here shows, the telegraph could transmit only certain letters of the alphabet. The needle could be deflected either to the left or the right. Different combinations of movements of either one or two needles were assigned different letters of the alphabet. Tavell was ‘wearing the garb of a Quaker’, or, as the transmitter put it, ‘KWAKER’.

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