HI 



ASTRONOMY. 



rich but compressed specimen of a globular cluster (right 

 ascension l.'-h. lorn., north jxilar distance 87 s 16'). In 

 this case (Ft;-. 7'.') the density towards the centre is 

 not gradual ; the condensation commences suddenly, and 

 the blase of light into which it is formed, appears 

 projected on a loose irregular ground of stars. The 

 neighbourhood of this cluster is very poor in stars 

 a circumstance which Sir W. Herschel remarked in 

 other os nos, and which he conceived might be due 

 to the stars being attracted to one |H>int, and formed 

 one cluster. The cluster situated at -Hi. '.Tim. 

 right anceiisiou, and 01 34' of north polar distance, 

 i\p|--ars like an unresolved nebula with instruments 

 of even considerable power ; and it is only when 

 viewed with the great light of high magnifying powers, 

 that faint traces of stars become apparent bn its sur- 

 face, and it takes a very tine sky and splendid in- 

 strument to show the grams of star-dust faintly visible 

 (Fig. 80). finer specimens of clusters, or rather nelm I.e, 

 tntrely resolved, are seen at Figs. 81 and 82. \\ may 



1 ... 80. 



!i.-l. and some powerful refracting tolescopos, it 

 shows some signs of reach-ability, Wing likened to a 

 curdling mass, or the breaking up of a mackerel sky. But 

 with the great mirror of Lord Rosse, the resolution is 

 complete, and it is broken up into distinct stars, which 

 are scattered in irregular masses through its body. The 

 great nebula of Andromeda (Fig. 84), is another very 

 conspicuous object of the class, and may even be 

 oeived with the naked eye on a line dark night. It 

 long, elliptical ray of light, nit her broader towards the 

 centre, and was compared, by its discoverer, Simon 

 Mai ius, to the llame of a lamp shining through a piece 

 of horn, \\ith the improved optical means of more 

 modern times, equally as with the imperfect telescope of 

 Marius, no signs of reachability have as yet appeared, 

 thou ; h the surface has been noticed to be dotted over 

 with innumerable stars, which are not, howe\er. -up 

 posed to be directly counceied ith it, being iu> 

 casual groups interposed between it and the s-nn. 



The majority of the uelmhe hitherto liiso, \cied now 



. KL 



Fig 82. 



consider the latter of those as the extreme boundary of 

 the clustering species ; after which the nebiihu, properly 

 so called, begin. As the reflecting telescope advances 

 more and more to perfection, we may, however, expect 

 that many object* will be won from the mysterious do- 

 main of nebula-, and placed to the account of the more 

 explicable clusters. 



The large clusters have some approach to regularity, 

 but this can scarcely be said of the more considerable 

 nebulae. The finest of those is, without doubt, that of 

 Orion (Fig. 83), which, for its various inequalities of 



Fif. 8J. 



upwards of 3,000 in number are mostly of a regular 

 Fin. M. 



form, being either circular or more or less elliptic, l 



Fl(t. 85. 



IP, its great extent, and tlio 



ti tin- form of the great promon' 



Ini-li jut ..ill fr the main body, constitute it one 



I.],- and mysterious of those objects. 



When examined with the two-feet mirror of Sir .lohn 



that of Andromeda. But there are many others ; and 



