Denoting by W the work in ergs done upon a cubic centimetre of the metal (=_fHdB or f HdI), he finds W =nips approximately, where n 47r is a number, called the hysteretic constant, depending upon the metal, and B is the maximum induction.
The hysteretic exponent is therefore much higher than in the case of iron, nickel and cobalt, for which its value is approximately I.6.