17 



■n AEGUS AND ITS SUREOUNDING NEBULA, &c. 



By F. Abbott, F.E.A.S., &c. . 



Eead at a meeting of the Eoyal Society of Tasmania, 9th 

 May, 1871. 



In the last paper I had the honour on bringing before 

 the Society I referred to a correspondence which was then 

 pending on the star v, and the attached nebula, in the con- 

 stellation Argo-Navis. It will be fresh in the minds of 

 many of the members of this Society that authorities, pre- 

 viously quoted, have confirmed the alterations which have 

 been recorded in this object. E. B. Powell, Esq., of Madras, 

 writing to the Eoyal Astronomical Society some observa- 

 tions on the binary star a Centauri, has a concluding note 

 thus : — "I have to observe that to Mr. Abbott must be 

 ascribed the first publication of the fact that v is no 

 longer in the dense portion of the nebula, where it was seen 

 by Sir John Herschel."— (F/t/e Monthly Notices E.A.S., Vol. 

 24, p. 172.) 



It was in March, 1865, that I first pointed out the fluctua- 

 tions in this object, through the Melbourne equatorial, to 

 Mr. Ellery at the Observatory, when the star ?? was out of 

 the nebula, and the altered figure of the dark space was 

 filled with 12th magnitude stars, richly coloured as described 

 in Monthly Notices E.A.S., Vol. 25, p. 192. 



Notwithstanding this in connection with all other evidence, 

 strong opposing influences have been brought to bear against 

 the movements which have been observed, although it is well 

 known to every astronomer that there is nothing stationary 

 in the universe. The distance of such objects as the nebula 

 about V Argus is in all cases so immensely great, their 

 position in the sky often unfavourable, and convenient 

 times for observing so far apart, that any alteration or physical 

 change may for centuries remain unknown. 



The late Sir William Herschel . writes, and is followed 

 by Sir John, thus : " Gravitation still further condensing and 

 so absorbing the nebulous matter, each in its immediate 

 neighbourhood might ultimately become stars, and the 

 whole nebula finally take on the state of a cluster of stars," 

 &c. — (Vide Outlines of Astronomy, htli edition, p. 640.) Mr. 

 Procter considers that an increased or decreased distance in 

 space may account for the fluctuations. 



The present object was observed and faithfully recorded 

 by Sir John Herschel when stationed at the Cape of Good 

 Hope in the year 1837. It is quite impossible to say what, 

 if any, alterations may have taken place in the nebula before 



