James Dewar

92
James Dewar bigraphy, stories - Chemists

James Dewar : biography

20 September 1842 – 27 March 1923

Sir James Dewar FRS (20 September 1842 – 27 March 1923) was a Scottish chemist and physicist. He is probably best-known today for his invention of the Dewar flask, which he used in conjunction with extensive research into the liquefaction of gases. He was also particularly interested in atomic and molecular spectroscopy, working in these fields for more than 25 years.

Selected publications

  • , G. D. Living and J. Dewar, Cambridge University Press, 1915

Career

In 1875, Dewar was elected Jacksonian professor of natural experimental philosophy at the University of Cambridge, becoming a fellow of Peterhouse. He became a member of the Royal Institution and later, replaced Dr. John Hall Gladstone in the role of Fullerian Professor of Chemistry in 1877. Dewar was also the President of the Chemical Society in 1897 and the British Association for the Advancement of Science in 1902, as well as serving on the Royal Commission established to examine London’s water supply from 1893 to 1894 and the Committee on Explosives. It was whilst he was serving on the Committee on Explosives that he and Frederick Augustus Abel developed cordite, a smokeless gunpowder alternative.

In 1867 Dewar described several chemical formulas for benzene.Proceedings of the Royal Society, 1867, vol. 6, p. 82 Ironically, one of the formulae, which does not represent benzene correctly and was not advocated by Dewar, is sometimes still called Dewar benzene.Baker and Rouvray, Journal of Chemical Education, 1978, vol. 55, p. 645

His scientific work covers a wide field – his earlier papers cover a wide range of topics; organic chemistry, Hydrogen and its physical constants, high temperature research, the temperature of the sun and of the electric spark, electro-photometry and the chemistry of the electric arc.

With Professor J. G. McKendrick, of Glasgow, he investigated the physiological action of light, and examined the changes which take place in the electrical condition of the retina under its influence. With Professor G. D. Liveing, one of his colleagues at Cambridge, he began in 1878 a long series of spectroscopic observations, the later of which were devoted to the spectroscopic examination of various gaseous elements separated from atmospheric air by the aid of low temperatures; and he was joined by Professor J. A. Fleming, of University College London, in the investigation of the electrical behaviour of substances cooled to very low temperatures.

Sir James Dewar at work His name is most widely known in connection with his work on the liquefaction of the so-called permanent gases and his researches at temperatures approaching absolute zero. His interest in this branch of physics and chemistry dates back at least as far as 1874, when he discussed the "Latent Heat of Liquid Gases" before the British Association. In 1878 he devoted a Friday evening lecture at the Royal Institution to the then recent work of Louis Paul Cailletet and Raoul Pictet, and exhibited for the first time in Great Britain the working of the Cailletet apparatus. Six years later, again at the Royal Institution, he described the researches of Zygmunt Florenty Wróblewski and Karol Olszewski, and illustrated for the first time in public the liquefaction of oxygen and air. Soon afterwards he built a machine from which the liquefied gas could be drawn off through a valve for use as a cooling agent, before using the liquid oxygen in research work related to meteorites; about the same time he also obtained oxygen in the solid state.

By 1891 he had designed and built, at the Royal Institution, machinery which yielded liquid oxygen in industrial quantities, and towards the end of that year he showed that both liquid oxygen and liquid ozone are strongly attracted by a magnet. About 1892 the idea occurred to him of using vacuum-jacketed vessels for the storage of liquid gases – the Dewar flask (otherwise known as a Thermos or vacuum flask) – the invention for which he became most famous. The vacuum flask was so efficient at keeping heat out that it was found possible to preserve the liquids for comparatively long periods, making examination of their optical properties possible. Dewar did not profit from the widespread adoption of his vacuum flask – he lost a court case against Thermos concerning the patent for his invention. While Dewar was recognised as the inventor, because he did not patent his invention there was no way to stop Thermos from using the design.