80 



Intelligence and Miscellaneous Articles. 



The following Table gives the position of the chief lines in the 

 spectra of these three types of stars, compared with that of our sun; 

 and this can be done with the same instrument for Venus and Mars. 

 One turn of the micrometer =2*71. 



Position of the chief lines in the Spectra of the Planets and Fixed 



Stars. 







In parts of the micrometer. 









1 



Venus. 



Mars. 



a. 

 Herculis. 







Pegasi. 



a 



Orionis. 



Arcturus. 



Mira 

 Ceti 



Vega. 



a 

 Persei. 



r 

 A =172 









1-98 











B =216 













213 









C =2-50 





a'=2-48 



'257 



2-64 











D*=3-22 



3-24 



a =3-25 



3-22 



3-22 



3-38 



318 



312 





S =3-51 





b =3-86 



3-83 







3-19 



3-62 





E =4-83 





c =4-24 



4-19 



415 



4-77 



4-31 





4-86 



b\ =5-09 



514 



d=5\\ 



511 



511 



509 



511 







X =5-62 





e =5-95 



5-99 



5-95 











F =6-27 



6-35 



/=6-81 



6-85 



6-78 



6-21 



6-77 



6-28 



630 



G =798 



801 



g =7-64 



7-68 



7-49 



7-98 



815 







H =9-40 



964 







8-43 



9-65 





915 



8-29 



W = 















1103 





From this Table an identity is manifest, as accurately as can be 

 proved by a comparison of the fundamental lines, between the various 

 red-coloured stars, and between the yellow stars and our sun. The 

 Table also shows the difference in the position of the lines in the white 

 stars of the type of Vega. 



It is curious that red stars of the seventh magnitude, like Lalande 

 12561, give a measurable spectrum, while this is not the case with 

 white stars of the same magnitude. This arises from the feeble dis- 

 persion of their light, by which separate bright lines are formed 

 pretty much- as in the nebulas. A light which is not dispersed, 

 though it be feeble, retains a remarkable intensity. Thus I could 

 distinctly see the separate sodium lines in the flame of an ordinary 

 small candle at a distance of 2 kilometres. 



It is to be remarked that in the red stars the dark lines are really 

 bands like those which the absorption of our atmosphere produces 

 in solar light. Thus the line D, is enormously broadened, far more 

 than the very fine sodium line. This proves that these stars are 

 surrounded by very absorbent atmospheres, the nature of which 

 cannot be made out until chemists can distinguish what belongs in 

 the spectrum to the nature of the substance from what depends on 

 the temperature. — Comptes Rendus, vol. lxiv. p. 774. 



* Sodium. 



. 



