Page:Proceedings of the Royal Society of London Vol 60.djvu/104

Rh pcrature of liquid air. If, instead of plotting the hysteresis loss and induction, the ordinary logarithms of these quantities are taken as coordinates, the curve, as shown in fig. 4, then obtained is Magnetic Permeability, fa., of Iron at Low 89 F ig. 4.

very nearly a straight line as far as the limit of an indttction of about 9000, and from the inclination of this line it is clear that the hysteresis loss, W, in watts per lln per 100 cycles is found to be related to the maximum induction B in C.Gr.S. units per square centimetre by the law W = — B1*53, or, if the lays* teresis loss is reckoned in ergs per cubic centimetre per cycle =2 W, then W' = 0'Q02 Br3fl, These results are quite in accordance