Heating -on the Magnetic Properties of Iron. 



151 



.after a very short time. At temperatures above this, no trace of any 

 rise has been observed. 



The question at once suggested itself whether iron which had been 

 .heated at a constant temperature with the effect of causing its hys- 

 teresis to pass a maximum and to become reduced, would have its 

 hysteresis again increased by exposure to more moderate temperatures, 



