BRUSH— GENERATION OF HEAT IN STEEL. 363 



the curve line. This was very gratifying in view of the fact that 

 observations for the normal cooling curve were made more than 

 two years ago, and checked only once since that time. 



Hardness was 18.5. 



Again heated above decalescence and annealed by cooling in 

 the furnace. 



Hardness remained 18.5, showing that the pre-vious heating and 

 quenching had no effect whatever on the hardness of this, pre- 

 sumably, very pure iron. 



Spontaneous generation and absorption of heat in recently 

 quenched nickel-chromium steel, would be a better descriptive title 

 for the present paper; but the subject matter is so intimately related 

 to that of the former papers, that it is thought best to retain the 

 former title for the sake of continuity. 



In conclusion, I can only express the hope that contemplated ex- 

 periments, on somewhat different lines, may throw more light on 

 these interesting phenomena. 



Cleveland, O., 

 April, 1917. 



