418 THE BEAUTIES OF NATURE chap. 



approaching us. By the same process it is 

 shown that some groups of stars are only 

 apparently in relation to one another. Thus 

 in Charles' Wain some of the stars are 

 approaching, others receding. 



I have already mentioned that Sirius, 

 though it seems, like other stars, so stationary 

 that we speak of them as "fixed," is really 

 sweeping along at the rate of 1000 miles a 

 minute. Even this enormous velocity is ex- 

 ceeded in other cases. One, which is numbered 

 as 1830 in Groombridge's Catalogue of the 

 Stars, and is therefore known as " Groom- 

 bridge's 1830," moves no less than 12,000 

 jniles a minute, and Arcturus 22,000 miles a 

 minute, or 32,000,000 of miles a day ; and 

 yet the distances of the Stars are so great that 

 1000 years would make hardly any difference 

 in the appearance of the heavens. 



Changes, however, there certainly would 

 be. Even in the short time during which 

 we have any observations, some are already 

 on record. One of the most interesting is the 

 fading of the 7th Pleiad, due, according to 

 Ovid, to grief at the taking of Troy. Again, 



