BY JOHN TEBBUTT, JTJN. ]31 



comparison, owing to the stars being situated in different parts 

 of the heavens, my observations being made without the assistance 

 of an astrometer. From very careful comparisons, however, I 

 considered its lustre to be equal to that of Beta (/3) Canis 

 Minoris. I, at the same time, compared it with Delta (B) Crucis 

 and Theta (0) Argus, to which I found it equal. This latter 

 estimate may be considered as accurate as can be formed by the 

 unaided judgment, the stars of comparison being moreover in 

 the same part of the heavens. At the close of January, of the 

 present year, I compared Eta (if) Argus with Sigma (<r) Orionis, 

 u Carinae, Theta (6) Argus, and Beta (/3) Canis Minoris. It 

 was not so bright as the last mentioned two ; the difference 

 between it and Sigma (cr) Orionis was scarcely perceptible, 

 though the latter may have been somewhat the brighter. It 

 appeared to be exactly equal to u CarinaB, which is a small star 

 distant about a degree and a half from it in a north-easterly 

 direction. From observations during last month, I find that its 

 magnitude is perceptibly less than that of u Carina3, which, being 

 very close to it, can easily and accurately be compared with it. I 

 have not contented myself with a comparison between it and one 

 or two stars near it, but have extended my observations to several 

 others, in order to avoid any errors which might arise from the 

 standard of comparison itself being variable. I am devoting 

 considerable attention to this star, with a view to the 

 determination of its time of minimum, magnitude at 

 minimum, and ratio of decrease and increase. It is very 

 probable that the minimum is not far distant ; the time 

 however, cannot be predicted, as the changes of this star have 

 hitherto been very irregular. From what has been said it 

 appears that Eta (77) Argus is one of the most interesting of the 

 class to which it belongs, and deserves continuous and close 

 observation. So far as the contrast between its maximum and 

 minimum magnitudes is concerned it may be regarded as the 

 Algol of the Southern Hemisphere. It appears from the notices 

 of the Royal Astronomical Society for February last that the 

 variations of Eta (rj} Argus have been made the subject of papers 

 by Mr. Abbott and Mr. Powell read before the Society. It is a 

 remarkable fact that the variable character of this star has so far 



