106 



F. W. Very — A Cosmic XJycle. 



and defined limits could give the exactly timed and sharply 

 defined occulations observed. Moreover the two bodies do not 

 differ greatly in size or in mass. A dark meteor-swaim would 

 have an extent relatively much greater than a stellar body of 

 nearly the same mass. Considering their great mass and close 

 proximity to the primary, the obscurity of these companions 

 remains one of the most singular facts known to astronomy. 

 The best explanation that has occurred to me is that the 

 companion originally separated as a complete anriulus and 

 remained long enough in the annular form to cool by reason of 

 the extensive radiating surface, before the ring was disrupted 

 and its material gathered into one body. 



The difference of type is much less in stars of composite 

 spectra, which, however, are not necessarily binaries, Dividing 

 the recently discovered spectroscopic binaries into two groups, 

 one for periods of only a few days, the other where the period 

 is several months, I find the following distribution by spectral 

 types, according to the divisions of McClean and the groups of 

 Miss Maury, omitting several pairs whose periods remain 

 unknown. 



Spectroscopic Binaries of Short Period. 



Star. 



Spectrum 



Div. or Group. 



Variation of Velocity. 



A. G. C. 10534* 







? 





610 km. 



12 Persei 



Div. 3 



(Group 11) 





51 



/x' Scorpii 



" la 



l 







460 



/3 Aurigae 



" 2 



( 



8) 





240 



a Urs. Min. 



" 4 



( 



13) 





6 



7) Aquilae 



" 3 



( 



" 12) 





50 



l Geminorum 



" 4 



( 



<{ 14) 





27 



k Pegasi 



" 3 



( 



12) 





79 



£ Urs. Majoris 



" 2 



( 



- 8) 





156 



w Draconis 



" 3 



( 



" 11) 





71 



Draconis 



" 4 



( 



13) 





50 



o Leonis 



" 3 



( 



" ]2) 





97 



A Andromedae 



" 4 ( " 15) 

 Mean variation of velocity 



18 





= 147 km. 



Spectroscopic Binaries of Long . 



Period. 



Star. 



Spectrum Div. 



or Group. 



Variation of Velocity. 



/3 Capricorni 



Div. 4 





(Group 14) 





40 km. 



a Aurigae 



" 4 and 3 





51 



| Urs. Majoris 



" 4 





( « 14) 





14 



(3 Scuti 



' 



? 







21 



rj Andromedae 



" 4 





( « 15) 





28 



X Draconis 



" 4 





( " 13) 





36 



ft Herculis 



" 4 





( " 15) 





LI 



-q Pegasi 



"4 ( " 14) 

 Mean variation of veloci 



ty - 



23 





. 28 km. 



* V Puppis. 













