438 GLOBULAR CLUSTERS. [SECT, xxxvn. 



and full of stars, constituting a family or society apart from 

 the rest, subject only to its own internal laws. To attempt 

 to count the stars in one of these globular clusters, Sir John 

 Herschel says, would be a vain task; they are not to be 

 reckoned by hundreds. On a rough computation, it appears 

 that many clusters of this description must contain ten or 

 twenty thousand stars compacted and wedged together in a 

 round space, whose apparent area is not more than a tenth 

 part of that covered by the moon ; so that its centre, where 

 the stars are seen projected on each other, is one blaze of 

 light (N. 225). If each of these stars be a sun, and if they 

 be separated by intervals equal to that which separates our 

 sun from the nearest fixed star, the distance which renders 

 the whole cluster barely visible to the naked eye must be so 

 great, that the existence of this splendid assemblage can 

 only be known to us by light which must have left it at 

 least a thousand years ago. These magnificent globular 

 or spheroidal aggregates of stars are so arranged that the 

 interior strata are more crowded and become more nearly 

 spherical as they approach the centre. A most splendid 

 object of this nature may be seen in the constellation 

 Hercules. 



Probably nine-tenths at least of the nebulous contents of 

 the heavens consist of spherical or elliptical forms, present- 

 ing every variety of elongation and central condensation. 

 Of these a great number have been resolved into stars, and 

 a great many present that mottled appearance which ren- 

 ders it almost certain that an increase of optical power 

 would decompose them. Those which resist do so on ac- 

 count of the smallness and closeness of the stars of which 

 they consist. Of 131 of these magnificent objects in the 

 southern hemisphere, two of them are pre-eminently 

 splendid. The globular cluster of a Centauri is beyond 

 comparison the finest of its kind, it is perfectly spherical 

 and occupies a quarter of a square degree ; the stars in it 

 are literally innumerable, crowding and densely aggregated 



