114 Prof. J. N. Lockyer. [May 9 r 



D 3 100 (maximum) 



4471 100 



4302 3 



Hence we might be justified in supposing that D 3 and 4471 are pro- 

 duced by the same gas, while it was probable that 4302 owed its 

 origin to a different one. 



Bat further experiment has given me one case in which D 3 shows 

 bright, while 4471 is entirely absent. I may now add that an equally 

 important line to 4471, one at 4026*5, with the dispersion em- 

 ployed, appears in the spectrum of broggerite, and both these lines 

 are wide and fluffy, like the lines of hydrogen, and are apparently 

 reversed. 



The line 4026' 5 has not been recorded by Young, though, as I have 

 stated, the frequency of appearances of 4471 represents the maximum ; 

 still, while this is so, the intensity of both these lines in the spectra 

 of the hottest stars is not surpassed even by those of hydrogen. 

 Hence, opinion as to their representing the same gas must be sus- 

 pended. 



Further, I have photographed a line at 4388, apparently coincident 

 with another important line in the same stars. Whether coming 

 from one source or two, in these three lines seen along with D 3 in the 

 gas obtained by me from broggerite, we have, it would seem, run 

 home the most important lines in the spectra of stars of Group III, 

 in which stars alone we find D 3 reversed. Should these results be 

 confirmed, the importance of the gas or gases they represent, at a 

 certain stage of the evolution of suns and planets, will be gathered 

 from the photograph of Bellatrix, accompanying the following Third 

 Note. 



Another case is afforded by a line a X 667 ; this is associated with 

 D 3 in broggerite and cleveite, but the yellow line has been seen in 

 monazite without X 667. It is almost certain, then, that these two 

 lines represent two gases. Certainty cannot be arrived at till a larger 

 quantity of gas has been obtained. 



Again the red line at X 6575, close to C, referred to in my previous 

 communication, is seen both in gummite and broggerite, but in one 

 case (gummite) it is seen without D 3 , and in the other with it ; in 

 one case (broggerite) without X614, and in the other with it. The 

 above conclusions hold here also. 



This line X 614, possibly coincident with a chromospheric line, has 

 been recorded in gummite and broggerite. It has been seen with D$ 

 (in broggerite) and without it (in gummite). 



I have said enough to indicate that the preliminary reconnaissance 

 suggests that the gas obtained from broggerite, by my method, is 

 one of complex origin. 



