James Alfred Ewing

From Academic Kids

Sir James Alfred Ewing (March 27, 1855 - January 7, 1935) was a British physicist and engineer, best known for his work on the magnetic properties of metals and, in particular, for his discovery of, and coinage of the word, hysteresis.



Born in Dundee, Scotland, the third son of a minister of the Free Church of Scotland and educated at West End Academy and the High School of Dundee, Ewing showed an early interest in science and technology.

In a family whose chief interests were clerical and literary, I took my pleasure in machines and experiments. My scanty pocket money was spent on tools and chemicals. The domestic attic was put at my disposal. It became the scene of hair-raising explosions. There too the domestic cat found herself an unwilling instrument of electrification and a partner in various shocking experiences.

Ewing graduated in engineering from the University of Edinburgh where his studied under William Thomson, 1st Baron Kelvin and Peter Guthrie Tait. During his summer vacations, he worked on telegraph cable laying expeditions, including one to Brazil, under Thomson and Fleeming Jenkin. In 1878, on Jenkin's recommendation, he was recruited to help the modernisation of Meiji Era Japan as one of the o-yatoi gaikokujin (hired foreigners). Serving as professor of mechanical engineering at the University of Tokyo, he was instrumental in founding Japanese seismology.

In 1883, Ewing returned to Scotland to work at the University College Dundee where he was appalled by the living conditions of many of the poorer areas of the town which he felt compared unfavourably with those in Japan. He worked fervently with local government and industry to improve amenities, in particular sewer systems.

In 1890, he took up the post of professor of mechanism and applied mechanics at King's College, Cambridge . At Cambridge, Ewing's research into the magnetisation of metals led him to criticise the conventional account of Wilhelm Weber. In 1890, he observed that magnetisation lagged behind an applied alternating current. He described the characteristic hysteresis curve and speculated that individual molecules act as magnets, resisting changes in magnetising potential. Ewing was a close friend of Sir Charles Algernon Parsons and collaborated with him on the development of the steam turbine, participating in the sea-trials of the Turbinia. He also researched into the crystalline structure of metals and, in 1903, was the first to propose that fatigue failures originated in microscopic defects or slip bands in materials.

In 1903, he became director of naval education at the Admiralty before becoming principal and vice-chancellor of the University of Edinburgh in 1916, a post he held until his retirement in 1929. From 1914 to 1917, he managed Room 40, the admiralty department of cryptanalysis, achieving some notoriety in the popular press.



  • Treatise on Earthquake Measurement (1883)
  • Magnetic Induction in Iron and Other Metals (1891)
  • The Steam Engine and other Heat Engines (1894)
  • The Strength of Materials (1899)
  • The Mechanical Production of Gold (1908)
  • Thermodynamics for Engineers (1920).

See also


  • Bates, L. F. (1946) Sir Alfred Ewing: A Pioneer in Physics and Engineering ISBN 1114517046
  • Pedlar, Neil, 'James Alfred Ewing and his circle of pioneering physicists in Meiji Japan', Chapter 8, Britain & Japan: Biographical Portraits Volume III, ed. J.E. Hoare, Japan Library, 1999. ISBN 1873410891

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