9 6 



INFRA-RED EMISSION SPECTRA. 



and to plot them to the same scale. The purpose of the present examina- 

 tion is to map the distribution of energy in the various spectra, hoping that 

 at some future time it may be possible to make a more extended study of 

 certain substances which show unusual emission spectra. 



RADIATION FROM ELECTRICALLY HEATED SOLIDS. 



Prominent among this group are a series of silicates, which have an 

 emission band in common at 2.88 p. (characteristic of Si0 2 ) which is as 



/ 2 3 4 5 6 



Fig. 63. Emission spectrum of albite. 



8JU 



sharp as any yet found in gases. The absorption spectra of many of these 

 compounds are recorded in Part III of these investigations (Carnegie 

 Publication No. 65). 



In order to give the reader some idea of the conditions under which 



