He invented magnets that could withstand the effects of percussion and ordinary temperature variations.
It was employed as a purely empirical formula by Bertrand and Barus, who calculated the values of the coefficients for several substances, so as to obtain the best general agreement with the results of observation over a wide range, at high as well as low pressures.
(Avenarius, 1863.) (General type.) (Becquerel, 1863.) (Tait, 1870.) (Barus, 1889.) (Holborn and Wien, 1892.) (Paschen, 3893.) (Steele, 1894.) (Holman, 3896.) (Stanfield, 1898.) (Holborn and Day, 1899.) See sec. 15.) For moderate ranges of temperature the binomial formula of M.