KXI'LOSIONS OF COAL CAS ANI All;. 



in;, 



of gas increases greatly as the density of the gas increases. The emission does not 

 vary directly as the density, but rather as the square root of the density,* as will 

 be seen from the following table. This same result was obtained from the experi- 

 ments in.-i'li- under similar conditions with tin- bolometer close up to the plate of 

 flimrite (see p. 388). 



TANLK XIX. 15-per-cent. Mixtures of Coal-gas and Air. Walls Black. 



Fluorite Window. 



C. akt. -from <J9 'cms. 



. from _ _ 

 I. from JSOcmt. 

 C.abt. from 3f/ n cms 

 "C. aks. from 

 '3.9.00 'C.at>*. from 



-. from Sfcmt 

 'rom SO Cms. 



. abs. -from <ff9cms. 

 lioo'C. abs frtm SOcns. 

 1800'C akt. from 36/ D cms. 



.on, 

 abt/fr.m 



Fig. 16. 



' The emission seems to vary more nearly as the density with mixtures of about half an atmosphere 

 density at high temperatures. 



