1892.] 



Spectra of some of the Brighter Stars. 



329 



Stars of Increasing Temperature. 



Stage 1. Immediately follow- 

 ing the stage of condensation 

 giving bright-line stars, the 

 bright lines from the interspaces 

 will be masked by corresponding 

 dark ones, due to absorption of 

 the same vapours surrounding the 

 incandescent meteorites, and these 

 lines will therefore vanish from 

 the spectrum. 



Owing to the interspaces being 

 restricted, absorption phenomena 

 will be in excess, and low-tem- 

 perature metallic fluting absorp- 

 tion will first appear. The 

 radiation spectrum of the inter- 

 spaces will now consist chiefly of 

 carbon. 



Under these conditions the 

 amount of continuous absorption 

 at the blue end will be at a 

 maximum. 



Stage 2. With further conden- 

 sation, the radiation spectrum of 

 the interspaces will gradually 

 disappear, and dark lines replace 

 the fluting absorption owing to 

 increase of temperature, though 

 this line absorption need not 

 necessarily resemble that in the 

 solar spectrum. 



Stage 3. (1.) The line ab- 

 sorption and the continuous 

 spectrum at the blue end will 

 diminish as the condensations are 

 reduced in number, as only those 

 vapours high up in the atmo- 

 spheres surrounding the conden- 

 sations will be competent to show 

 absorption phenomena in conse- 

 quence of the bright continuous 

 spectrum of the still disturbed 

 lower levels of those atmospheres. 



The spectra of stars given in 

 the third table answer these re- 

 quirements. They show no bright 

 lines under normal conditions. 



The dark flutings in the visual 

 spectrum agree very closely in 

 position with the flutings seen in 

 the flame spectra of manganese, 

 lead, and iron. The evidence 

 afforded by the photographs 

 proves the actual presence of 

 carbon radiation. 



The photographs show a con- 

 siderable amount of continuous 

 absorption in the ultra-violet and 

 violet. 



The spectra consist of nume- 

 rous dark metallic lines, but they 

 do not exactly resemble the solar 

 spectrum, a. Tauri and 7 Cygni 

 are types of stars at this stage. 



(1.) These conditions are satis- 

 ied by such stars as a. Cygni, 

 Rigel, Bellatrix, 8 Orionis, and 



Yirginis. In these there is 

 no continuous absorption at the 

 3lue end, the spectra consisting 

 of simple line absorption. 



