LONDON, EDINBURGH, and DUBl^ J, PATtHTjjg 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[SIXTH SERIES.] 



SEPTEMBER 1918. 



XIX. A Comparative Study of the Flame and Furnace Spectra 

 of Tron. By G. A. Hemsalech, Honorary Research Fellow 

 in the University of Manchester*. 



[Plate X.] 

 § 1. Introduction. 



THE principal laboratory means of vaporizing substances 

 at definite temperatures are provided by the flame 

 and the electric-tube resistance furnace. If the determining- 

 factor in the emission of luminous radiations by a metal 

 vapour in these two widely different sources of light were 

 the same, namely heat, then the spectra observed in the 

 various flames should be the same as those given by the 

 furnace at corresponding temperatures. Thus at 1850° C. 

 the furnace should emit a similar spectrum as the mantle of 

 the air-coal gas flame, or at 2700° C. the furnace spectrum 

 of a metal vapour should be the same as that observed in the 

 oxy -acetylene flame. Now Dr. King, who has made a most 

 exhaustive examination of the spectrum of iron as given by 

 a tube furnace at various temperatures, has compared his 

 results with those found for the flame-spectra of the same 

 element by Dr. de Watteville and myself f, and, in con- 

 clusion, he has assigned certain values to the effective tempe- 

 ratures of our flames, which do not at all agree with those 

 generally attributed to these flames. There is no doubt that 

 a comparison of observational results obtained with different 



* Communicated by Sir E. Rutherford, F.R.S. 



t A. S. King, Astrophysical Journal, vol. xxxvii. p. 275 (1913). 



Phil. Mag. S. 6. Yol. 36. No. 213. Sept. 1918. P 



