CHAP. VII.] A CHEMICAL CLASSIFICATION OF STARS. 07 



Iron, calcium, and manganese at arc temperatures. 



Carbon (flutings) at arc temperatures. 



Manganese and iron (flutings) at a still lower temperature. 



In the last chapter I stated the results arrived at recently with 

 regard to the appearances of the lines of the above substances in stars 

 of different temperatures, and the definitions of the different groups or 

 genera to be subsequently given are based upon the map given 

 on page 62, together with more minute inquiries on certain additional 

 points the examination into which was suggested as the work went 

 on. 



So far as the inquiry has .ii present gone, the various most salient 

 differences to be taken advantage of for grouping purposes are repre- 

 sented in the following stars, the information being derived from the 

 researches of Professor Pickering* and Mr. McClean,f as well as from 

 the Kensington series of photographs. 



Hottest Stars. 



Two stars in the constellation Argo (( Puppis and y Argus }). 



Alnitam (e Orionis). This is a star in the belt of Orion shown on 

 maps as Alnilam. Dr. Budge has been good enough to make inquiries 

 for me, which show the change of word to have been brought about by 

 a transcriber's error, and that the meaning of the Arabic word is "a. 

 belt of spheres or pearls." 



Stars of intermediate Temperature. 



Ascending Series. 



/3 Crucis. 

 Tauri. 

 Rigel. 

 a Cygni. 



[ 1 



Polaris. 



Aldebaran. 



Descending Series* 



Achernar. 



Algol. 



Markab. 



[. ] 



Sirius. 



Proeyon. 



Arcturus. 



* Astro-pk^s.Journ., vol. v. p. 92, 1897. 



t Spectra of Southern Stars. 



The spectrum of this star contains bright line?, but -when these occur with 

 dark lines, the latter alone have to te considered for purposes of chemical classi- 

 fication. 



F 2 



