1 6 THE BORDERLAND OF SCIENCE. 



milky light of a nebula must be regarded (if these 

 conceptions of Sir W. Herschel be just) as the centre 

 of a scheme as vast as the solar system, and possibly 

 far vaster. 



Another conception, even more overwhelming, is that 

 of the distances separating these Milky Ways from 

 each other. For vast as are the dimensions of the 

 several Milky Ways, including our own, the distances 

 separating one from another are far vaster belonging, 

 indeed, to a higher order of vastness altogether. 



And here the question will suggest itself, What 

 position (according to these views) does our own Milky 

 Way bear among the others ? We have already quoted 

 Herschel's opinion as to the dimensions of our galaxy, 

 which he supposed to be far surpassed by those of many 

 other galaxies. But he also came to an opinion as to 

 the relative age of our Milky Way, which cannot fail 

 to strike the reader as singularly indicative of the 

 daring originality of his mind. c If it were possible,' 

 he says, ' to distinguish between the parts of an in- 

 definitely extended whole, the nebula we inhabit might 

 be said to be one which has fewer marks of profound 

 antiquity than the rest. To explain this idea perhaps 

 more clearly, we should recollect that the condensation 

 of clusters of stars has been ascribed to a gradual 

 approach ; and whoever reflects on the numbers of 

 ages that must have passed before some of the clusters 

 could be so far condensed as we find them at present, 

 will not wonder if I ascribe a certain air of youth and 

 vigour to many regions of our sidereal stratum.' 



