James Dewar

Sir James Dewar, 1910

Sir James Dewar (born September 20, 1842 in Kincardine , Scotland , † March 27, 1923 in London , England ) was a Scottish physical chemist .

Life

Dewar was the son of a wine merchant (his parents died when he was fifteen). He attended the Kincardine Parish School and the Dollar Academy and studied at the University of Edinburgh , where he was assistant to Lyon Playfair , and at the University of Ghent , where he continued his training with August Kekulé . In 1875 he became Jacksonian Professor of Experimental Science at Cambridge University and became a Fellow of Peterhouse College. In 1877 he succeeded John Hall Gladstone Fullerian Professor of Chemistry at Cambridge. After his death, he was in the Golders Green Crematorium in London crematedwhere his ashes are.

plant

Dewar investigated, among other things, oxidation products of nicotine , the conversion of quinoline into aniline , the physical constants of hydrogen , chemistry in electrical discharges and their temperature as well as the temperature of the sun, high-temperature research, spectrophotometry and the physiological effect of light (electrical measurements on the retina with JG McKendrick).

Dewar proposed a structure for benzene in 1867 that did not solidify. The substance he describes is still known today as Dewar benzene ; it was first produced in 1962.

From the 1870s onwards he studied low temperature physics and wrote several treatises on liquid air . As early as 1874 he was using a double-walled, evacuated metal vessel in his experiments.

In 1878 he presented the apparatus and the experiments of Louis Paul Cailletet and Raoul Pictet to liquefy oxygen and air (first public demonstration in England) in front of the Royal Institution . It also produced solid oxygen. In 1891 he built an apparatus at the Royal Institution that could produce liquid oxygen on a large scale. In doing so, he demonstrated the magnetic properties of liquid oxygen and liquid ozone.

In 1893, Dewar invented a double-walled evacuated transport and storage vessel for liquid gases made of mirrored glass, which is called the Dewar vessel after him , and which is still based on the principle of vacuum jugs and containers for storing dry ice and liquid gases. In 1881 , Adolf Ferdinand Weinhold described a forerunner of such a vessel, but without mirroring the inside of the glass, in his book Physical Demonstrations for the Representation of Solid Mercury by Cooling. Although Dewar was considered the inventor of the Dewar vessel that made him famous, he did not apply for a patent and lost a patent lawsuit against the Thermos company, which marketed it.

He examined spectroscopically components of the air that could be separated at low temperatures and electrical properties at low temperatures.

With Frederick Augustus Abel he invented smokeless powder , which was used in the military, and the explosive cordite . With Henri Moissan Dewar in 1897 succeeded the liquefaction of fluorine and 1898 of hydrogen. In 1899 he allowed hydrogen to solidify and, at 14 Kelvin, generated the lowest temperature up to that point at which all substances, with the exception of helium, are in the solid state.

Honors and memberships

Dewar was nominated for the Nobel Prize several times . He was a Fellow of the Royal Society (1877) and the Royal Society of Edinburgh (1869). He received the Rumford Medal of the Royal Society in 1894, their Davy Medal in 1909 and their Copley Medal in 1916 . In 1901 he held the Bakerian Lecture and he held several Christmas Lectures at the Royal Institution, of which he was a member. In 1899 he was elected to the American Philosophical Society , 1907 to the National Academy of Sciences and 1920 to the Académie des Sciences in Paris. In 1904 he was knighted as a Knight Bachelor , received an honorary doctorate from Oxford, received the Gunning Victoria Medal of the Royal Society of Edinburgh and received the Lavoisier Medal . In 1897 he became President of the Chemical Society and in 1902 of the British Association for the Advancement of Science . In 1906 he received the Mateucci Medal and in 1908 the Albert Medal. In 1893/94 he was on the royal commission for the water supply of London and on the committee for explosives. In his honor, Mount Dewar in Antarctica is named, a lunar crater and a road on the grounds of the University of Edinburgh.

literature

• JS Rowlinson: Sir James Dewar, 1842-1923: A Ruthless Chemist, Routledge 2012
• George Downing Liveing ​​(Ed.): James Dewar. Collected Papers on Spectroscopy, Cambridge University Press, 1915

Individual evidence

1. ↑ J. Dewar: On the Oxidation af Phenyl Alcohol, and a Mechanical Arrangement adapted to illustrate Structure in the Non-saturated Hydrocarbons . In: Proc. Royal Soc. Edinburgh . 6,62, 1867, p. 96.
2. ^ EE Van Tamelen, SP Pappas: Chemistry of Dewar Benzene. 1,2,5-tri-t-butylbicyclo [2.2.0] hexa-2,5-dienes . In: Journal of the American Chemical Society . 84, No. 19, 1962, pp. 3789-3791. doi : 10.1021 / ja00878a054 .
3. ^ Thomas O'Connor Sloane: Liquid Air and Liquefaction of Gases . Norman W. Henley & Co., New York 1900, pp. Chapter XI, especially page 232.
4. ↑ Vacuum vessel cut open for demonstration purposes and used by Dewars ( memento of the original from July 14, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , Science Museum, London 
5. ^ Adolf Ferdinand Weinhold: Physical demonstrations (instructions for experimenting in lessons at grammar schools, secondary schools and industrial schools) . Quandt & Handel, Leipzig 1881, p. 479 Fig. 362.
6. ↑ Frank James: Dewar, James . In: Chemistry Explained . Advameg Inc. Retrieved May 22, 2008.
7. ↑ List of members since 1666: Letter D. Académie des sciences, accessed on November 6, 2019 (French). 
8. ^ William Arthur Shaw: The Knights of England. Volume 2, Sherratt and Hughes, London 1906, p. 417.