VASTNESS OF THE UNIVERSE. 271 



vinces in the same empire, subject to common 

 rules, governed by a common power. 



But the stars which we see with the naked eye 

 are but a very small portion of those which the 

 telescope unveils to us. The most imperfect 

 telescope will discover some that are invisible 

 without it; the very best instrument perhaps 

 does not show us the most remote. The number 

 of stars which crowd some parts of the heavens 

 is truly marvellous : Dr. Herschel calculated 

 that a portion of the milky way, about 10 de- 

 grees long and 2J broad, contained 258,000. In 

 a sky so occupied the moon would eclipse 2000 

 of such stars at once. 



We learn too from the telescope that even in 

 this province the variety of nature is not ex- 

 hausted. Not only do the stars differ in colour 

 and appearance, but some of them grow periodi- 

 cally fainter and brighter, as if they were dark 

 on one side, and revolved on their axes. In other 

 cases two stars appear close to each other, and 

 in some of these cases it has been clearly estab- 

 lished, that the two have a motion of revolution 

 about each other ; thus exhibiting an arrange- 

 ment new to the astronomer, and giving rise, 

 possibly, to new conditions of worlds. In 

 other instances again, the telescope shows, 

 not luminous points, but extended masses of 

 dilute light, like bright clouds, hence called 

 nebula. Some have supposed (as we have noticed 



