DISTBIBUTION OF THE STAHS. 177 



telescope of 18 inches aperture, with a field of view of 

 about a quarter of a degree. Herschel made 3400 gages 

 of this kind. These gages indicate the number of stars 

 visible in the field of his telescope, and from this number 

 he deduced the corresponding lengths of the visual rays. 

 Assuming the distance of the nearest of the fixed stars in 

 accordance with the estimate of Struve, we find that, 

 according to Herschel, the stars upon the borders of our 

 stratum, in the constellation of the Eagle, are at such a 

 distance as light requires 7000 years to traverse and 

 from the remoter stars, light would require 13,000 years 

 to come to us. 



The figure on the next page is designed to represent 

 the form of the nebula in which our own solar system is 

 placed, according to the views advanced by Sir "William 

 Herschel. 



The great nebulae of the heavens, such as those of Orion 

 and Andromeda, Herschel conjectured to be Milky Ways 

 like our own, only of much superior dimensions. The 

 nebula of Andromeda, which he concluded to be the near- 

 est, he placed at a distance 2000 times greater than that 

 of stars of the first magnitude. 



This hypothesis respecting the phenomena of the Milky 

 Way, would be tenable, provided it were true, 1st, that 

 the stars are uniformly distributed through space ; and 2d, 

 that Herschel was able, with his telescope of 20 feet, to 

 penetrate to the limits of our stratum. 



With regard to the first of these hypotheses, we find 

 that Herschel himself subsequently abandoned it as unten- 



8* 



