( 1^" ) 



Unfortunately, of tlie great number of spectroscopic double stars 

 discovered as yet (in Lick Observatory Bulletin N'. 79 a number 

 of M7 is given) the orbit elements of only very few are known. 

 They give, arranged according to their spectra: 



Group XII— XIV a 'F— G) 



Solar type 



« Aurigae 0.185 



/Draconis 0.120 



(W Sagittarii 0.005) 



(X Sagittarii 0.001) 



I Pegasi 0.117 



^l Pegasi 0.234 



Group XII— XIV ac 

 «Ursae min. 0.00001 

 SGeminorum 0.0023 

 1] Aquilae 0.0029 



(f Cephei 0.0031 



Group XV (K) 

 i5 Herculis 0.061 



Of the K stars only one representative occurs here, so neither 

 this material offers anything that could help us to test the results 

 obtained about this stellar type. But all the same, some remarkable 

 conclusions may be derived from this table. It appears here that 

 notwithstanding their small number the Orion stars evidently surpass 

 the others in mass, while the Sirius stars seem also to have a some- 

 what greater mass than the solai- stars. Very striking, however, 

 is the small mass of the c stars approaching towards a. Hence the 

 c stars combine a very great luminosity icitli a very small mass, and 

 consequently their density must he excessively small. If it should be 

 not merely accidental that the three regularly variable stars of short 

 period, occurring in Maury, all happen to show c characteristics 

 and a real connection should exist between this particularity of 

 spectrum and the variability, we may reasonably include into the 



1) In the case of ^ Ursae a has been taken equal to the semi major axis of the 

 relative orbit ; hence this number is proportionally too large by an unknown 

 number of times. 



•) Assumed period 100 days, velocity in orbit 32..Ü kilometres. 



