402 



Mr. J. N. Lockyer. On the Cause of [Nov. 21, 



revealed in the phenomena of variability, that is to say, the vari- 

 ability of the bodies we are now considering should be different 

 in kind as well as in degree from that observed in some cases in 

 bodies like the Sun or a Lyras, taken as representing highly 

 condensed types. There is also little doubt, I think, that future 

 research will show that when we get short period variability in bodies 

 like these, we are here really dealing with the variability of a close 

 companion." 



The recent work of Chandler* on the colours of these interesting 

 objects, and the relation of colour to period, furnishes further tests of 

 the theory which I suggested as to their origin. 



Variability due to Subsidiary Swarms. 



Briefly, this was that in the case of the stars of Group IT, which 

 spectroscopic observations show to be composed of uncondensed 



Fia. 1. — Diagram sl.ovring the probable origin of variability in condensing swarms. 



* ' Astr. Journ./ ]S T o. 179-180. 



