122 IN STARRY REALMS. 



crowd the field of view with a multitude of brilliant stars, 

 in which the curious eye will find charming configura- 

 tions ; in one of these clusters notably a horseshoe, in the 

 other a beautiful system of triangles. Many of the stars 

 are of a ruddy hue, and as contrasted with other clusters 

 the smaller and inconspicuous stars are comparatively 

 absent. "We can, as it were, see right through the 

 entire group at every part to the space beyond. Such 

 a collection of gems, and so exquisitely set, will extort 

 admiration from everybody ; I do not remember to have 

 seen any one disappointed at this spectacle. But it requires 

 some previous acquaintance with a few facts in astronomy 

 to fully realise all that the picture represents. Unhappily 

 we are not able to supply the most important piece of 

 information which will naturally be asked : we are not 

 able to give the actual dimensions of this system. The 

 case is in this respect very different from that of the moon 

 or of Saturn. There the arts of the astronomer have been 

 successful in the attempt to measure and even to weigh ; 

 but in the stellar regions proper our knowledge of the 

 weights and the distance is always scanty, and not infre- 

 quently entirely wanting. This is so in the case of the 

 cluster in Perseus. We do not know the distance by 

 which it is separated from us. The methods which astro- 

 nomers are in the habit of using in such investigations 

 have, I believe, never been yet applied to the cluster in 

 Perseus. The belief no doubt exists that the only methods 

 available would be inapplicable to such an object. 



In seeking the distance of a fixed star, the ordinary 

 method is to select some other star in the neighbourhood 

 apparently, but which is really very much farther behind, 



