1888.] 



of the various Species of Heavenly Bodies. 



59 



The Bands 9 and 10. 



With regard specially to the bands 9 and 10, which include between 

 them a bright space which I contend is the second fluting of carbon, 

 I may add that if this view is sound, the absence of 10 should mean 

 a broad carbon band, and this is the condition of non-condensation, 

 though not the initial condition. The red flutings should therefore 

 be well marked — whether broad or not does not matter ; but they 

 should be dark and not pale. Similarly the absence of band 9 means 

 non-condensation. 



Therefore 9 and 10 should vary together, and as a matter of fact 

 we find that their complete absence from the spectrum, while the 

 metallic absorption is strong, is a very common condition (1, 2, 6, 16, 

 26, 32, 39, 40, 46, 54, 60). 



That this explanation is probably the true one is shown by further 

 consideration of what should happen to the red flutings when 9 and 

 10 are present. As the strong red flutings indicate condensation, 

 according to my view this condensation (see ante) should pale the 

 other flutings. This happens (3, 8, 13, 28, 35, 45, 30; and last, not 

 least, among the examples, I give 50, a. Orionis). 



III. Results of the Discussion. 



The Line of Evolution. 



I have gone over all the individual observations recorded by Duner, 

 and, dealing with them all to the best of my ability in the light 

 afforded by the allocation of the bands to the various chemical sub- 

 stances, the history of the swarms he has observed seems to be as 

 follows : — 



(1) The swarm has arrived at the stage at which, owing to the 

 gradual nearing of the meteorites, the hydrogen lines, which appeared 

 at first in consequence of the great tenuity of the gases in the inter- 

 spaces, give way to carbon. At first the fluting at 473 appears (as in 

 many bright-line stars), and afterwards the one at 517. This is very 

 nearly, but, as I shall show subsequently, not quite, the real begin- 

 ning of the group, and the radiation is now accompanied by the 

 fluting absorption of Mg, Fe, and Mn — bands 7, 2, 3. This is the 

 absorption produced at the temperature of the oxy-coal-gas flame, 

 while the stars above referred to give us the bright line of Mn seen 

 at the temperature of the bunsen. 



(2) The bright band of carbon at 517 narrows and unveils the Mg 

 absorption at band 8. We have 8 now as well as 7 (both represent- 

 ing Mg), added to the bands 2 and 3, representing Fe and Mn, and 

 these latter now intensify. 



(3) The spacing gets smaller; the carbon, though reduced in 



