Temperature, on the Hysteresis Loss in Iron. 133 



function of the induction. As in the case of iron, the 

 hysteresis losses, for very small inductions, are larger than 

 those given by the equation, and as the induction increases 

 beyond about 6000 the hysteresis increases less rapidly to a 



Fiff. 10. 



maximum value. Then, as the temperature is raised, the 

 hysteresis falls while the induction is still increasing. 

 Finally, the hysteresis and induction both decrease very 

 rapidly. For the straight part of the curve the equation 

 giving the hysteresis as near as can be determined is 

 W = -l4H" S8 B — 1000. The smaller the magnetic force the 

 higher the temperature at which the maximum hysteresis 

 occurs ; and, as in the case o£ iron, this temperature for any 

 magnetic force is practically the same as that giving the 

 maximum permeability with the corresponding magnetic 

 force. 



In conclusion I wish to express my thanks to Professor 

 J. J. Thomson for useful suggestions and kindly interest 

 during the progress of the work, and to Mr. G. F. G. Searle 

 for help in the preliminary experiments. 



Cavendish Laboratory, Cambridge. 



