118 PROCEEDINGS OP THE AMERICAN ACADEMY. 



rent in disintegration of the carbon, it follows that no definite tempera- 

 tures can be given above the point of inflection. Lucas's measurements, 

 therefore, cannot be said to throw any light upon the question whether 

 the intensity of radiation of incandescent bodies reaches a finite limit as 

 demanded by the Wien-Planck formula. The lower portion of the 

 curve shows no approach to such a maximum. Whether the study of 

 radiation, wave length by wave length, up to the temperature of the 

 crater will be found to do so remains to be seen. Far beyond that tem- 

 perature experiments with carbon can probably never be carried ; so 

 that the final determination of this point must probably be reached by 

 experiments on some more refractory material. 



In the prosecution of portions of this investigation 1 have received 

 valuable aid from Drs. C. H. Sharp and Leopold Kann and from Mr. 

 L. W. Hartman, to all of whom I desire to express my obligations and 

 extend my hearty thanks. 



Physical Laboratory of Cornell University, 

 April 24, 1901. 



