STELLAR CLUSTERS. 



That these are still clusters, of which the component stars are 

 indistinguishable by reason of their remoteness, there are the 



Fig. 15. 



Fig. 14. 



Fig. 16. 



strongest evidence and most striking analogies to prove. Every 

 augmentation of power and improvement of efficiency the tele- 

 scope receives, augments the 

 number of nebulae which are 

 converted by that instrument 

 into clusters. Nebulae which were 

 irresolvable before the time of Sir 

 W. Herschel, yielded in large 

 numbers to the powers of the in- 

 struments which that observer 

 brought to bear upon them. The 

 labours of Sir J. Herschel, the 

 colossal telescopes constructed by 

 Lord Eosse, and the erection of 

 observatories in multiplied num- 

 bers in climates and under skies 

 more favourable to observation, 

 have all tended to augment the 



number of nebula) which have been resolved, and it may be ex- 

 pected that this progress will continue, the resolution of these 

 objects into stellar clusters being co-extensive with the improved 

 powers of the telescope and the increased number and zeal of 

 observers. 



A theory was put forward to explain these objects, based npon 

 views not in accordance with what has just been related. It was 

 assumed hypothetically that the nebulous matter was a sort of 

 luminous fluid diffused through different parts of the universe ; 

 that by its aggregation on certain laws of attraction, solid lumi- 

 nous masses in process of time were produced, and that these 

 nebulae grew into clusters. 



It would' not be compatible with the limits of this Tract, and 

 the objects to which it is directed, to pursue this speculation 



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