Smithsonian Report, 1939. — Harrison 



Plate 2 





1. Typical portions of Spectrograms Taken in One Type of Quantitative 

 spectrograph ic analysis. 



In this method each line is photographed in such a way that it decreases in intensity along its length. 



mm I 



2. TYPICAL ABSORPTION SPECTROGRAM. 



The long lower spectrum is of the unabsorbed light; the three upper spectra were taken with some of the 

 "hafnium crystals" in the light beam, and show transparency in the green, beginning absorption in the 

 blue and violet regions, and opacity in the ultraviolet. 



