Dewar, James (20.09.1842–27.03.1923) was an English chemist and physicist and a Fellow of the Royal Society (1877). Born in Kincardine (Scotland). Graduated from the University of Edinburgh (1861). In 1875–1923 he was professor at the University of Cambridge and in 1877–1923 at the Royal Institution in London.
His research in physics was in the field of heat, low-temperature physics, optics and radioactivity. In 1872 he developed methods of measuring heat capacity at low temperatures and found that it decreases as the temperature falls. In 1892 he invented a vessel for storing liquefied gases (the Dewar vessel). In 1898 he obtained liquid hydrogen and in 1899 solid hydrogen. In 1871 he proposed structural formulas for benzene and pyridine.
The B. Rumford Medal (1894), the A. Lavoisier Medal (1904), the C. Matteucci Medal (1906) and others.