Swan, Sir Joseph Wilson

SUBJECT AREA: Electricity, Photography, film and optics

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b. 31 October 1828 Sunderland, England

d. 27 May 1914 Warlingham, Surrey, England

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English chemist, inventor in Britain of the incandescent electric lamp and of photographic processes.

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At the age of 14 Swan was apprenticed to a Sunderland firm of druggists, later joining John Mawson who had opened a pharmacy in Newcastle. While in Sunderland Swan attended lectures at the Athenaeum, at one of which W.E. Staite exhibited electric-arc and incandescent lighting. The impression made on Swan prompted him to conduct experiments that led to his demonstration of a practical working lamp in 1879. As early as 1848 he was experimenting with carbon as a lamp filament, and by 1869 he had mounted a strip of carbon in a vessel exhausted of air as completely as was then possible; however, because of residual air, the filament quickly failed.

Discouraged by the cost of current from primary batteries and the difficulty of achieving a good vacuum, Swan began to devote much of his attention to photography. With Mawson's support the pharmacy was expanded to include a photographic business. Swan's interest in making permanent photographic records led him to patent the carbon process in 1864 and he discovered how to make a sensitive dry plate in place of the inconvenient wet collodian process hitherto in use. He followed this success with the invention of bromide paper, the subject of a British patent in 1879.

Swan resumed his interest in electric lighting. Sprengel's invention of the mercury pump in 1865 provided Swan with the means of obtaining the high vacuum he needed to produce a satisfactory lamp. Swan adopted a technique which was to become an essential feature in vacuum physics: continuing to heat the filament during the exhaustion process allowed the removal of absorbed gases. The inventions of Gramme, Siemens and Brush provided the source of electrical power at reasonable cost needed to make the incandescent lamp of practical service. Swan exhibited his lamp at a meeting in December 1878 of the Newcastle Chemical Society and again the following year before an audience of 700 at the Newcastle Literary and Philosophical Society. Swan's failure to patent his invention immediately was a tactical error as in November 1879 Edison was granted a British patent for his original lamp, which, however, did not go into production. Parchmentized thread was used in Swan's first commercial lamps, a material soon superseded by the regenerated cellulose filament that he developed. The cellulose filament was made by extruding a solution of nitro-cellulose in acetic acid through a die under pressure into a coagulating fluid, and was used until the ultimate obsolescence of the carbon-filament lamp. Regenerated cellulose became the first synthetic fibre, the further development and exploitation of which he left to others, the patent rights for the process being sold to Courtaulds.

Swan also devised a modification of Planté's secondary battery in which the active material was compressed into a cellular lead plate. This has remained the central principle of all improvements in secondary cells, greatly increasing the storage capacity for a given weight.

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Principal Honours and Distinctions

Knighted 1904. FRS 1894. President, Institution of Electrical Engineers 1898. First President, Faraday Society 1904. Royal Society Hughes Medal 1904. Chevalier de la Légion d'Honneur 1881.

Bibliography

2 January 1880, British patent no. 18 (incandescent electric lamp).

24 May 1881, British patent no. 2,272 (improved plates for the Planté cell).

1898, "The rise and progress of the electrochemical industries", Journal of the Institution of Electrical Engineers 27:8–33 (Swan's Presidential Address to the Institution of Electrical Engineers).

Further Reading

M.E.Swan and K.R.Swan, 1968, Sir Joseph Wilson Swan F.R.S. , Newcastle upon Tyne (a detailed account).

R.C.Chirnside, 1979, "Sir Joseph Swan and the invention of the electric lamp", IEE

Electronics and Power 25:96–100 (a short, authoritative biography).

GW