Dewar, James (1842-1923)

Chemist and physicist, born in Kincardine, Fife, E Scotland, UK. He studied chemistry at Edinburgh, and in 1875 became professor at Cambridge. Two years later he also became professor at the Royal Institution, London, where he lived, lectured, and pursued a wide range of experimental research; he visited Cambridge rarely. In the 1870s he invented the Dewar flask (or thermos flask), using it in his studies of low temperatures and gas liquefaction. With Frederick Abel he invented cordite, for long the British standard military propellent. Every gas had now been liquefied and solidified except one - helium. Dutch physicist Heike Kamerlingh Onnes managed to liquefy helium using Dewar's techniques in 1908, and Dewar was then able to achieve temperatures within a degree of absolute zero (273°C/459°F) by boiling helium at low pressure. Dewar also carried out work in spectroscopy, particularly concerned with the absorption spectra of metals. He investigated properties such as chemical reactivity, electrical resistance, strength, and phosphorescence at low temperature. Feathers, for example, were found to be phosphorescent at these temperatures.