388 



THE STELLAR UNIVERSE. 



light. The other, fig. 12, is at a distance so much greater, that even to the 

 most powerful instruments it presents only the appearance of a faint nebulous 

 patch. 



One of the most splendid objects of this class to be seen in the heavens, is 

 the great nebula in the constellation of Orion. Let the eye be directed to the 

 three well-known stars composing what is called the Belt. Immediately below 

 these, and very nearly parallel to them in direction, will be seen three stars 

 at nearly equal distances asunder, the two lower of the third and the upper of 

 the fourth magnitude. If the middle star of these three be attentively viewed 

 with the naked eye, the observer will find that it wants distinctness. It will 

 be found to present a hazy appearance. If a common telescope be directed to 

 it, it will be evidently perceived to be a nebula. In fine, the appearance it 

 presents in a twenty-feet reflector is exhibited in the annexed drawing, fig. 13. 



The following are the observations of Sir John Herschel upon this ob- 

 ject : 



" I know not how to describe it better than by comparing it with a curdling 

 liquid, or a surface strewed over with flocks of wool, or to the breaking up of 

 a mackerel sky, when the clouds of which it consists begin > to assume a 

 cirrous appearance. It is not very unlike the mottling of the sun's disk, only, I 

 if I may so express myself, the grain is much coarser and the intervals darker, | 

 and the flocculi, instead of being generally round, are drawn into little wisps. 

 They present, however, an appearance of being composed of stars, and their 

 aspect is altogether different from that of resolvable nebulae. In the latter we 

 fancy by glimpses that we see stars, or that, could we strain our sight a little 

 more, we would see them ; but the former suggests no idea of stars, but rather 

 of something quite distinct from them." 



Sir William Herschel, who had previously examined it, says : 



" In the year 1774, the 4th of March, I observed the nebulous star which is 

 the 43d of the Connaissance des Temps, and is not many minutes north of the 

 great nebulae : but at the same time I also took notice of two similar, but much 

 smaller nebulous stars, one on each side of the large one, and at nearly equal 

 distances from it. In 1783 I examined the nebulous star, and found it to be 

 faintly surrounded with a circular glory of whitish nebulosity, faintly joining 

 it to the great nebula. About the latter end of that year I remarked that it 

 was not equally surrounded, but most nebulous toward the south. In 1784 I 

 began to entertain an opinion that the star was not connected with the nebu- 

 losity of the great nebula of Orion, but was one of those which are scattered 

 over that part of the heavens. In 1801, 1806, and 1810, this opinion was fully 

 confirmed by the gradual change which happened in that great nebula to which 

 the nebulosity surrounding the star belongs ; for the intensity of light about 

 the nebulous star had by this time been considerably reduced by the attenua- 

 tion or dissipation of the nebulous matter, and it seemed now to be pretty 

 evident that the star is far behind the nebulous matter, and that, consequently, 

 its light in passing through it is scattered and deflected so as to produce the 

 appearance of a nebulous star." .... "When I viewed this interesting ob- 

 ject in December, 1810, I directed my attention particularly to the two nebu- 

 lous stars by the sides of the large one, and found they were perfectly free 

 from every nebulous appearance, which confirmed not only my former surmise 

 of the great attenuation of the nebulosity, but also proved that their former 

 nebulous appearance had been entirely the effect of the passage of their feeble 

 light through the nebulous matter spread out before them. The 19th of Jan- 

 uary, 1811, I had another critical examination of the same object, in a very 

 clear view, through the forty-feet telescope ; but, notwithstanding the superior 

 light of this instrument, I could not perceive any remains of nebulosity about 



