F. J. Rogers — Magnesium as a Source of Light. 



503 



1879.* It will be seen that the results from Table I, are quite 

 in accordance with those of that observer and sustain his state- 

 ment that of all artificial illuminants the magnesium light 

 approaches sunlight much more nearly than does any other. 





; r 







■ ' 



r— ■■ 























5J 



p 































P 



,' \ 









\ . 























CO 











'M 























e 





JL 





\m 

























































S" 









\ 





\ 

























-;.. 









V 



. \ 

































._ 



%.. 







































■—--'. 





































"- 







: =Tv7^ 























•430 

 G 



•590 

 D 



II. 



Temperature of Burning Magnesium. 



An important question in regard to the magnesium light is 

 that of the temperature at which combustion takes place. 

 Flame temperatures are not well known. Kossettif has found 

 1350° for the hottest part of a Bunsen flame and 640° to 940° 

 for a stearine candle flame. As I knew of no experimental 

 data whatever on the subject of the temperature of burning 

 magnesium, I attempted to measure it by means of the E. M. 

 •F. produced in a thermo-element composed of platinum and 

 platinum-iridium, when the element was placed in the flame. 

 A thermo-element of those materials had been previously cali- 



- Proc. Am. Acad, of Arts and Sciences, 1879-80, p. 236. 

 \ Annalen der Physik, Beiblatter, I. p. 615, II, p. 333. 



