440 



The Bev. Walter Sidgreaves 



[Jan. 22, 



helium lines single and dark. This is the second spectral conjunc- 

 tion, and, unlike the tirst, it is retarded on the stellar conjunction, 

 which of necessity occurs at the time of least light ; and the retarda- 

 tion is about 24 hours, between the periodic dates of 7-4 and 7-19. 



w-^^a? v^/oci/y arteZ Ji^ax /J^ec/^ra/ t^csJyfa.c€/ns7z^ •+■ 



1 



^ > 



.Jrlajc velocity S^ yK ex.x ^fi}ec^?a^ c^iji^^jlctce ^nero^ — 



We have here direct indication of elliptical motion, as may be 

 seen in the diagram projected on the screen. Suppose an elliptic orbit 

 of a star S about another star occupying the focus nearer to Earth, 



^^ t Eambaut, ' On the Parallax of the Double Stars,' MontJily Notices, B.A.S., 

 vol. 50, p. 305. 



