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Dewar, Sir James

chemistry temperature flask temperatures

[dyoo er] (1842–1923) British chemist and physicist: pioneer of low temperature studies and the chemistry of metal carbonyls.

Son of a wine-merchant, Dewar became attracted to chemistry at Edinburgh University and spent a summer in Ghent in laboratory. In 1869 he went to teach chemistry at the Royal Veterinary College in Edinburgh. Although he was never interested in teaching students, he was a popular society lecturer on a wide range of scientific topics, and in 1875 became Jacksonian Professor at Cambridge. He was probably elected because of his work in physiological chemistry and was perhaps expected to do more of it; in fact he found the laboratory so poor that he was glad to be appointed also in 1877 to the Professorship of Chemistry at the Royal Institution, London. Thereafter he lived and worked in London, visiting Cambridge only briefly and infrequently in order to abuse his staff there for idleness and to visit G D Liveing (1827–1924), professor of chemistry; they collaborated in spectroscopic research for 25 years. Dewar had a strangely wide range of research interests, which he maintained with his own hands or with assistants, never having students or founding a ‘school’. In the early 1870s he invented the Dewar flask (domestically a Thermos flask), a double-walled glass flask with the inner walls reflective and the space between them evacuated; heat is only slowly passed to or from the contents. From 1877 he worked on the liquefaction of gases, using the flasks for storage. He used method for making oxygen, on a scale which allowed him to study low temperatures; and by 1898 he made liquid hydrogen in quantity and the solid in 1899, at a temperature below 14 K. At this temperature all known substances become solid, except helium. He tried to liquefy helium, discovered on Earth in 1895, but did not succeed. With he invented cordite. He worked on specific heat capacities, electrical effects of very low temperatures, metal carbonyls, diffusion, high vacua, coal tar bases, dissociation of molecules at high temperatures, emission and absorption spectra, soap films (he made them over 1 m in diameter) and the Sun’s temperature. A small, brusque Scot, he was unsurpassed in diversity and productivity as an experimentalist.

Dewey, John (1859-1942) [next] [back] Dew, Thomas Roderick

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