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Foucault|fuko, ˈfuːkəʊ|
The name of J. B. L. Foucault (1819–1868), French physicist, used attrib. and in the possessive to designate experiments or discoveries made, or apparatus designed, by him; as Foucault current, an eddy current; Foucault (knife-edge) method, Foucault test, a method of testing lenses and mirrors for surface irregularities; Foucault('s) pendulum, a pendulum designed to demonstrate the rotation of the earth by the rotation of its plane of oscillation; Foucault prism, a polarizing prism resembling a Nicol prism but having the two halves separated by a film of air.
1852Phil. Mag. 4th Ser. III. 331 (heading) A mathematical theory of M. Foucault's pendulum experiment. 1882L. Wright Light xi. 251 A large Foucault prism is only about one-fourth the cost of a Nicol of the same aperture. 1883Atkinson tr. Ganot's Physics (ed. 11) 869 The currents..produced in solid conductors and which are converted into heat, are often spoken of as Foucault currents. 1923Glazebrook Dict. Appl. Physics IV. 329/1 For the investigation of spherical aberration errors Foucault's original knife-edge method is still frequently employed. 1930L. C. Martin Introd. Appl. Optics I. 204 In case a prism is wanted for purposes of ultra-violet polarimetry, the Foucault type..is employed. Ibid. 257 (caption) The Foucault knife-edge test. 1931Discovery May 164/1 A knowledge of the rotation of our world might be gained by such means as the Foucault pendulum or the gyro-compass. 1952F. Twyman Prism & Lens Making (ed. 2) xi. 373 Correcting mirrors by local polishing with the help of the Foucault test. 1953P. Kemp A.C. Electr. Engin. (ed. 8) x. 96 These e.m.f.s..set up local circulating currents known as Foucault or Eddy Currents and give rise to a loss of power. 1966McGraw-Hill Encycl. Sci. & Technol. IX. 618 A Foucault pendulum is a spherical pendulum suspended so that its plane of oscillation is free to rotate. |