PERSONALIA

THE 1946 NOBEL PRIZE IN PHYSICS

The Nobel Prize in Physics for 1946 was awarded on November 16 of the current year to P. W. Bridgman for his work in the field of the physics of ultra-high pressures and, in particular, for the apparatus that made it possible to attain pressures on the order of several hundred thousand atmospheres. Percy William Bridgman was born on April 21, 1882. In 1904 he graduated from Harvard University (USA). Within the walls of this university, where he became professor of physics in 1919, almost all of his scientific activity has taken place, devoted entirely to the physics of ultra-high pressures. In this field Bridgman is responsible for the principal experimental ideas—self-sealing closures, a conical chamber with a support, the use of carboloy, and others—which enabled him to extend the range of pressures accessible for quantitative physical investigations from 3,000 atm at first to 20,000, then to 50,000 and, finally, to 100,000 atm, and to reach record pressures of up to 425,000 atm. He carried out extensive studies of compressibility, phase transitions, viscosity, and other properties of matter. In particular, he obtained experimental proof of the absence of a critical point on the melting curve, discovered a large number of polymorphic transformations, including the irreversible transition of yellow phosphorus into black, and discovered a special form of material failure under high pressure, the so-called “pinch effect.” A brief outline of his forty years of work, which led to a more than hundredfold increase in the range of technically attainable pressures and to the emergence of an entirely new branch of physics, was given by Bridgman himself in one of his recent articles (Russian translation, see UFN, XXX, nos. 3–4, 305, 1946).

Bridgman is the author of a number of books, of which The Physics of High Pressure and The Logic of Modern Physics are available in Russian translation. Recently he published an exhaustive critical review of all work in the field of high-pressure physics up to 1946 (see UFN, XXXI, nos. 1, 2, and 3, 1947).

For his work, in 1917 he was awarded the Rumford Medal of the American Academy of Sciences, of which he is a member; in 1932, the Cresson Medal of the Franklin Institute; and in 1933, the Roebuck Medal of the Royal Netherlands Academy of Sciences.