180 



SCENERY OF THE HEAVENS. 



CHAPTER X. 



STAR-SYSTEMS. NEBULA. 



AR more astonishing than any of the details upon which we 

 have hitherto dwelt, are those relating to the class of celestial 

 objects we have now to consider, the investigation of which 

 is at present the highest branch of practical astronomy. In 

 directing our attention to them, we leave what may compa 

 ratively be called home regions, strange as the phrase appears, 

 when we recollect the distance intervening between us and the 

 nearest of the stars. But such language is strictly appropriate 

 with reference to the stars visible to the naked eye, and reached 

 by ordinary telescopic aid. They form our firmament or cluster, 

 near the centre of which the solar system is supposed to be 

 situated. Yet besides this province with which we are connected, incalculably vast as 

 it is, perfectly inestimable both in length, breadth, depth, and height, there are other 

 provinces within view, equally as capacious, distinct firmaments or clusters, scattered 

 through those territories of the universe that are accessible to our gaze; and could we be 

 removed to any of them, the whole of that great scheme of existence apparently circum 

 scribed by the Milky Way, might seem compressed into a small globular patch in space, 

 or sprawling spot, only to a trifling extent bedimming the azure of the heavens the 

 aspect presented by these star-systems, clusters, or nebulae to ourselves. 



It is a reasonable supposition that stars which are classed as belonging to the inferior 

 orders of magnitude, only appear to be so generally, because of their greater distance. 

 Now it is observable, that the most brilliant, or those of the first, second, and third 

 magnitudes, are pretty evenly distributed over the surface of the heavens ; but those of 

 the fourth, fifth, and sixth magnitudes appear in crowds towards the margin of the Milky 

 Way, while that remarkable zone of light is plainly demonstrated to be an enormous 

 aggregation of minute stellar objects, very expressively characterised as "star-dust." 

 Hence the suspicion naturally arose, that there was some connection between the Galactic 

 circle and the other portions of the heavens, so that the whole might form one great system. 

 The extensive celestial surveys laboriously executed by Herschel his telescopic gauging 

 or sounding of the sphere contributed to confirm this idea ; and all subsequent investiga 

 tions, as those of Sir John Herschel in the southern hemisphere, have tended to the same 

 result. So far, therefore, from being fortuitously dispersed through space, as was once 

 supposed, the stars forming our firmament are definitely arranged ; and the particular shape 

 of the whole mass or cluster, as it would appear to spectators in remote clusters, has been 

 examined and approximately sketched. The whole visible creation of stars is conceived to 

 form a stratum or layer, extending to an immense but limited distance, and thin, in 

 proportion to the length and breadth. If our position therefore is towards the central 

 regions of this stratum, we shall obviously see a great gathering of stars, agglomerated into 

 one mass, looking towards the elongations, forming an appearance answerable to that of 

 the Milky Way ; but looking towards either of the surfaces of the stratum, we shall see a 

 far lesser number of stars, appearing also more distinct and scattered, answering to the 

 aspect of the other parts of the heavens. Supposing likewise the stratum, on one side, to 

 be split down the middle, the appearance in that direction will be that of the Milky Way, 



