68 



rj ARGUS AND ITS NEBULA. By P. Abbott, F.R.A.S., 

 F.U.M.S. 



[Read l^th November, 1871.] 



I beg to bring under the notice of tlie Society somo 

 preparatory results arrived at by the Council of the Royal 

 Astronomical Society, relative to the fluctuations of the Nebula, 

 &c., about the object v Argus. 



lu the Monthly Notices R.A.S. there appears the following 

 note, together with two additional papers and drawings from 

 Hobart Town. 



** Oil account of the interest attached to the question of the 

 variability of the nebula of tj Argus, the Council have determined 

 to print as well Mr. Abbott's communications as the remarks upon 

 them by the late Sir J. F. W. Herschel, and the Astronomer 

 Royal. For convenienc of reference it may be mentioned that Mr. 

 Abbott's former papers are printed in the Monthly I^otices, vol. xxi. , 

 p. 230, (June 18G1); vol. xxi v., p. 2, (November 18G3), with plate; 

 vol. XXV., p. ]92, (April 18G5, paper dated 18th February) ; and 

 vol. xxviii., p. 200, (May 18G8, paper dated 29th February), with a 

 plate ; and that there is a paper by Sir J. F. W. Herschel, vol. 

 xxviii., p. 225, ((June 18G8 ; and one by him and Lieut. Herschel, 

 vol. xxix., p. 82, (January 18G9), with five plates." — Ed. 



The Council have referred the subject to the Astronomer 

 Royal, who makes some comments on previous observations 

 to which I have temporarily replied as notes and queries, 

 pending the appearance of the object in a favourable position 

 for new observations, which will be about the month of 

 February, when the notes from the Astronomer Royal will 

 be dealt with seriatim. 



The following passages occur in Mr. Airy's remarks on the 

 subject : — 



* ' T duly received the packet of papers relating to Mr. Abbott's 

 observations on 77 Argus ; and with these I have perused also the 

 preceding papers in various volumes of the Monthly Notices. The 

 subject is really a very puzzling one. 



"■ As regards stars only the map of 1870, and the map of 1871 

 have so much difference (not a great deal) that I conceive them to 

 be certainly independent ; and yet they have so much similarity 

 as to give strcng j^robability to their faithful representation of the 

 visible objects. See in particular the line of four stars convex 

 towards 7? Argus.'' 



" These four stars have some agreement, not quite good, with 

 four of Sir J. Herschel's. But other stars in the concavity of the 

 bend are wanting in Sir J. Herschel's. 



K -^ # -jf -if I do concede to Mr. Abbott the merit of first 

 pointing out that the nebula has shifted its position with regard to 

 the star rj Argns, and has changed its form materially, both which 

 points I regard as certain. * -Jf- * * •* 



' ' Allow me to suggest that papers of this kind o'.ight to be pre- 



