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POPULAR SCIENCE MONTHLY. 



animation that the individual stars do not fall far below the limit of 

 visibility, several being of about the seventh magnitude. 



Another notable cluster of the same general nature is that in Per- 

 seus. This constellation is situated in the Milky Way, not far from its 

 region of nearest approach to the pole. In the figure of the constella- 

 tion the cluster forms the handle of the hero's sword. It may be seen 



Fig. 6. The Great Cluster in Hercules, as Photographed with 

 the Crossi.ey Reflector of the Lick Observatory. 



in the evening during almost any season except summer. To the naked 

 eye it seems more diffused and star-like than Prasepe; in fact, it has 

 two distinct centers of condensation, so that it may be considered as a 

 double cluster. 



The two clusters last described may be resolved into stars with the 

 smallest telescopes. But in the case of most of these objects the in- 



