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 1850,” moves no less than 12,000 - 
miles 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, 
oe gy ‘aah ay 
