266 Effects of Heating on the Magnetic Properties of Iron, 

 Table III. Cyclic Curves for Ring. 



Table IV. Permeability Curves for Ring. 



In order to ascertain whether the effects could be due to the 

 iron taking up anything from the atmosphere, a couple of specimens 

 were, at the suggestion of Professor Ewing, sealed up in exhausted 

 bulbs and heated in the same oven with others exposed to air. 

 No evidence, however, was found of any difference between the 

 iron heated in vacuo, and that heated in air. 



There is nothing to show that when baked iron is left for 

 long time it recovers from the condition produced by baking. But 

 in all cases the iron is restored to its original state of low 

 hysteresis by reannealing. 



