EVOLUTION IN ASTRONOMY AND PHILOLOGY. 35 



even the sun itself may be inhabited, and that 

 its chemical activity is limited to the photo- 

 sphere, which they imagine to be separated 

 from the body of the sun by a screen of dense 

 clouds. It was even at first suggested that 

 the so-called "willow-leaves" of the photosphere 

 might be living organisms of some description. 



A short time ago, it was believed that the 

 Galaxy was a nebula, or star- system, to which 

 all the visible heavenly bodies (except the other 

 nebulas, then regarded as independent star- 

 systems) belong, but spectrum analysis has now 

 shown us that all nebulae are not of the same 

 constitution, and it is at present held that they 

 are not star-systems totally independent of our 

 own, but masses of matter in a less organised 

 condition than the rest. According to this 

 view, the whole of the visible heavens, whether 

 stars or nebulae, would form one vast system, 

 though some portions, such as the Galaxy, the 

 Magellanic Clouds, some of the resolvable 

 nebulae, and various star-clusters, appear to 

 form subordinate systems of their own, more or 

 less independent of the remainder. 



Apart from all speculation, it is incontestable 

 that the moon is more or less dependent on the 



D2 



