THE BIRTH AND DEATH OF WORLDS 409 



more or less nebulous masses there are few now to doubt, though 

 we may not yet know how. The recognition of this probable 

 origin we owe to Immanuel Kant. 



It is not without interest nor without significance that 

 while Kant's ill-fated little work was lying upon the musty 

 shelves of the booksellers, unnoticed and unread, the splendid 

 mind of Herschel should have been travelling towards much 

 the same conception by an entirely different route. Herschel 

 had a boundless curiosity to know of everything which the 

 heavens contained ; the nebulous patches of the sky, as we 

 have seen, interested him deeply. When he began, the number 

 known was not large. His first catalogue offered to the Royal 

 Society a thousand. He made two more. These wisps of light 

 fascinated him as they baffled him ; he hardly left off thinking 

 about them to th end of his life. 



The most interesting discovery that Herschel made about 

 them was a seeming gradation in what might be termed the 

 degree of nebulosity. Some of them seemed clearly nothing 

 but cloud, some seemed mottled as though they contained 

 denser masses. These denser masses graduated into clusters 

 of stars. From the milky nebulosity seen in Orion, up to a 

 coarse cluster like that of the Pleiades, there was no line of 

 demarcation. At first Herschel was inclined to think that with 

 a sufficiently powerful telescope all the nebulae might be re- 

 solved into star-heaps. Conceiving that each of these assem- 

 blages might be in grandeur and structure something like unto 

 our own Milky Way, he made a little jest one day to the effect 

 that he had discovered fifteen hundred new universes. 



Later on his views changed. He came to see that there 

 were apparently nebulous stars, twinkling points surrounded by 

 a sort of halo. He came to the conclusion that the nebulosity 

 about the star is not of a starry nature. It was in thus wise 

 that he came to the view that some of the nebulae at least 

 might be " a shining fluid " of a nature wholly unknown to us. 



From this came a vast conception, engaging in its simplicity, 

 immense in its embrace. It was that the gradations he had 

 noted in the appearance of these clusters in reality represented 

 epochs of development, stages of world growth. He conceived 

 that some " clustering power " might be at work converting 

 these diffused and milky masses into brighter and more con- 



