Clevcite and other new Gas Lines in the Hottest Stars, 57 



Relative Intensities in Stars of decreasing Temperature of the Lines 

 in the principal and subordinate Series of Gas X. 



Star. 



Principal series 

 (A 3964-9). 



1st subordinate 

 series 

 (X 4388-1). 



Zxxix subordinate 

 series 

 (A 4437-7). 



. — 



5 



7 



1 





2 



3 







2 



1 





































Relative Intensities in Stars of decreasing Temperature of the Lines 

 in the 1st and 2nd subordinate Series of Helium. 





1st subordinate 



2nd subordinate 



Star. 



series 



series 





(A 4471-6). 



(4121-0). 





10 



4 





3 



2—1 





1 



1 , 



























The above detailed investigations show that while helium and 

 gas X behave differently as regards their appearance in stars, the 

 constituent series of each, so far as we can at present study their 

 behaviour, do not exhibit any remarkable differences. Thus in the 

 stars of increasing temperature there is a steady increase of intensity 

 of the three series of lines of gas X, and of the two series of helium 

 lines, while in the case of cooling stars there is a decrease in the 

 intensity of each series. 



In the case of gas X it will be seen that the principal series is not 

 intensified to the same extent as the first subordinate series in passing 

 from Rigel to Bellatrix, and this seems to suggest that the molecules 

 corresponding to the principal series do not survive so high a tem- 

 perature as those which produce the lines of the first subordinate 

 series. 



There is, however, no sufficient reason for regarding the three 

 series of gas X or of helium as representing separate constituents of 



