BY JOHN TEBBUTT, JUX. ' 133 



magnitude ; whereas, it is at the present time only an average 

 star of the second magnitude, being about equal to Alpha (a) 

 Trianguli Australis. It was observed by Taylor, Brisbane, 

 Johnson, and Rumker; but I cannot speak as to their estimation 

 of its magnitude, as I have not their catalogues at my command. 

 According to the photometric observations made by Sir John 

 Herschell at the Cape of (rood Hope, its magnitude was some- 

 what greater than that of Alpha (a) Trianguli Australis. I 

 cannot for a moment suppose that Lacaille committed an error in 

 recording Beta (/3) Argus in 1751 as of the first magnitude. 

 Considering, then, the circumstances connected with this star, we 

 may regard it also as belonging to the list of stars suspected to 

 be variable. There are other Southern stars which might well 

 claim attention if the magnitudes assigned to them in the 

 catalogues of Lacaille and the British Association are to be relied 

 on. 



I shall here advert to an interesting discovery which I made 

 on the evening of the 25th July, and which suggests the conclu- 

 sion that Eta (77) Argus is not the only variable star in that part 

 of the heavens which it occupies. On comparing the stars of the 

 sixth magnitude in its neighbourhood with a chart constructed 

 from data afforded by the British Association catalogue, I was 

 struck with the fact that B.A.C. 3679, a star of the sixth magni- 

 tude, had vanished from its place in the heavens. At all events 

 it was not visible in my telescope of 3J inches aperture, which is 

 capable of showing stars down to the ninth and tenth magni- 

 tudes. Instead also of finding both B.A.C. 3680 and 3683, I 

 could distinguish one only. The distance between these two stars, 

 according to the catalogue just mentioned, is rather more than a 

 minute of arc, a quantity appreciable in a small telescope, yet an 

 instrument furnished with a power of 120, and capable of separa- 

 ting easily Alpha (a) Crucis and Alpha (a) Centuri exhibited the 

 star under the single aspect. Possibly B.A.C. 3680 and 3683 

 may be members of a double star and now in the same visual 

 line. This is a subject which I should like to have investigated 

 by means of the large equatorial telescope of the Observatory. 

 The only remaining star of the three in question is situated about 

 half a degree north-west of Eta (77) Argus, and is surrounded 



