10 THE BORDERLAND OF SCIENCE. 



established, before Sir W. Herschel abandoned the 

 theory as untenable. In the picture and paper of 1785 

 we find our sun one of innumerable stars, not all equal, 

 indeed, nor spread with mathematical uniformity, but 

 still all comparable with each other in magnitude and 

 distributed with a general approach to uniformity. In 

 1802 we find Sir W. Herschel regarding our sun as one 

 of a set of stars which he called insulated stars, and 

 the Milky Way as composed of stars wholly different 

 in their nature and arrangement. I quote his own 

 words lest the reader should be disposed to doubt the 

 very possibility that in so many treatises a theory 

 should have been assigned to Sir W. Herschel which he 

 had himself rejected. After saying that our sun, 

 magnificent as its system is, must yet be regarded as 

 only a single individual of the species he denotes by 

 the term ' insulated star,' he presently proceeds : ' To 

 this may be added that the stars we consider as in- 

 sulated are also surrounded by a magnificent collection 

 of innumerable stars called the Milky Way. For though 

 our sun, and all the stars we see, may truly be said to 

 be in the plane of the Milky Way, yet I am now con- 

 vinced by a long inspection and continued examination 

 of it, that the Milky Way itself consists of stars very 

 differently scattered from those which are immediately 

 about us.' And a few pages further on the very prin- 

 ciple of the method of star-gauging, and the conclu- 

 sions as to the shape of the Milky Way, are thus 

 unmistakeably called in question. 'In my sweeps of 

 the heavens,' says Herschel, 'it has been fully ascertained 



