148 Royal Society : — 



the ends of the transverse axis. In this aspect the nebula resembles 

 in form the planet Saturn when the ring is seen nearly edgewise. 

 Attentively viewing it with higher powers, magnifying respectively 

 760, 1060, and 1480 times, and under the most favourable circum- 

 stances which have presented themselves, I have discovered within the 

 nebula a brilliant elliptic ring, extremely well defined, and apparently 

 having no connexion with the surrounding nebula, which indeed has 

 the appearance of a gaseous or gauze-like envelope, scarcely inter- 

 fering with the sharpness of the ring, and only diminishing somewhat 

 its brightness. This nebulous envelope extends a little further from 

 the ends of the conjugate than from the ends of the transverse axis ; 

 indeed, it is but very faintly prolonged, and only just traceable 

 towards the preceding and following stars. There is a star near its 

 border, northwards, in the projection of the conjugate axis. 



The breadth or thickness of the ring is, unlike that of Saturn, 

 nearly uniform, or equal in every part, so that its form most probably 

 is either really elliptic, and seen by us in a line nearly perpendicular 

 to its plane ; or, if really circular, and seen foreshortened, a section 

 throughout any part of it, limited by the internal and external dia- 

 meters, must be a circle. In other words, it will be like a circular 

 cylinder bent round. It could scarcely fail to bring to my mind the 

 annular nebula in Lyra, especially as there is a conspicuous central 

 star (proportionally, however, much brighter than that which is in the 

 centre of that nebula), and yet the resemblance is only rudely in 

 form, for this ring is much more symmetrical and more sharply de- 

 fined, suggesting the idea of a solid galaxy of brilliant stars. 



The ring is not perfectly uniform in brightness, the south-pre- 

 ceding part being slightly the most vivid. The transverse axis is 

 inclined to the parallel of declination about 13°. A series of micro- 

 metrical measures of the length and breadth of the ellipse gives a 

 mean of 26"*2 for the transverse, and 16"'6 for the conjugate axis. 



The accompanying drawing has not been at all corrected by these 

 measures, but is the result of several sketches made during different 

 observations, and is a faithful transcript of the appearance of the 

 nebula to my eye, when most favourably seen. 



The object is, as may be supposed, one of extreme difficulty, re- 

 quiring in the highest degree the combination of light and definition 

 in the telescope, and a favourable state of atmosphere, — which will 

 further appear when I state that it was not until I was favoured with 

 an unusually tine night, and had applied a power of 1480, that the 

 whole of the details were brought out. 



I confess I have been greatly impressed by the revelation of this 

 most wonderful object, situated on what perhaps we may consider as 

 the very confines of the accessible or recognizable part of the universe, 

 affording ground for the inference that more gorgeous systems exist 

 beyond our view than any we have become acquainted with. 



I am, &c, William Lassell. 



"On the Fossil Remains of a long-tailed Bird (Archeopteryx 

 macrurus, Ow.) from the Lithographic Slate of Solenhofen." By 

 Prof. Richard Owen, F.R.S. 



