Clusters and Nebulae. . 57 



rays. It is 392 H. who calls it a large, poor (that is in numbers), 

 but brilliant cluster. A very large field is required to do it 

 justice, which will include towards its sf edge 12 Monocerotis, 

 6 mag., a fine yellow star. 



If we go lower still towards the horizon, till we reach a line 

 joining Procyon and Sirius, about one-third of the distance 

 from the latter we shall detect by sweeping, a nebulous patch 

 in the finder — 



13. 50 M. [Monocerotis). A low power will here show us 

 what Smyth justly calls a superb and very rich object, com- 

 posed of stars from 8 to 16 mag., with spots of splendour 

 indicating yet further masses. H. gives it a diameter of 10' 

 to 12', and says the stragglers extend over a circle of 30', as 

 large as the moon. The mode in which it loses itself every 

 way in the surrounding galaxy is very beautiful, as well as sug- 

 gestive with regard to the constitution of that wonderful zone. 

 The whole neighbourhood is superb, and will be swept over 

 with a delighted gaze, minute sparklings breaking out 

 throughout the whole extent of the field, and indicating the 

 starry nature of the nebulous ground which fills it. A very 

 moderate aperture, even under four inches, will suffice to indi- 

 cate this resolvability, which will increase with every increase 

 of light, till in the field of the great reflectors of Herschel, 

 Schroter, and Lassell, the multitude of faintly- glittering points 

 would prove that the whole of this vast stratum encompassing 

 us on every side, is composed of stars : and every one of these 

 literally millions of minute stars is a witness of the omni- 

 presence and omnipotence of its Creator. 



We will now turn to 



14. Prcesepe in Cancer (44 M) . This celebrated cluster, 

 which was well-known to the ancients, has been already referred 

 to under No. 5 of our Double Stars (Int. Obs., I. 277), and 

 may probably not be a stranger to us ; however, it could not 

 with propriety be omitted from the present list. It offers a 

 perfect example of the process of nebular resolution, being 

 barely resolvable without the telescope,* showing its compo- 

 nents in the finder, and being widely opened out with high 

 powers, while the reverse of this operation enables us readily to 

 comprehend how clusters, fully separated to the naked eye, 

 would become gradually compressed, and at length nebulous, 

 if progressively removed to greater depths in space. The 

 whole of Praesepe is too extensive to be included in an ordi- 

 nary field; it is sub-divided into several groups, among which, 



* Arago says, "It is impossible for mere unaided vision in any instance to 

 separate" the stars. Their existence may, however, be recognized with little 

 difficulty, giving a sparkling character to the mass. I have found the cluster 

 much brighter by oblique vision. 



