BOOK OF NATURE LAID OPEN. 213 



netary bodies are not to be found in precisely the 

 same place for any two successive days together, the 

 stars, for instance, in the constellation of Ursa Ma- 

 jor, or the Great Bear, have not been observed to 

 alter their situation, with respect to each other, since 

 the creation of the world. But there are few rules 

 without exception; and here it must be observed., 

 that new stars have been discovered, which were un- 

 known to the ancients, and many of those which ap- 

 peared in old catalogues arc not now visible, while 

 numbers seem gradually to vanish, and others ap- 

 pear to have a periodical increase and decrease of 

 magnitude. 



All the fixed stars, however, have an apparent 

 motion round the heavens once in twenty -four hours ; 

 for, although that of the star nighest the pole, and 

 consequently called the polar star, be so impercepti- 

 ble as to be scarcely distinguished, yet, even that star 

 appears to move in a very small circle; and this ima- 

 ginary motion is occasioned by the same cause as 

 produces the rising and setting of the sun; viz. the 

 revolution of the earth on its axis. 



Though the number of the fixed stars, visible to 

 the naked eye, fall infinitely short of what a super- 

 ficial observer might be apt to imagine, yet, from 

 the great resemblance they bear to each other, and 

 the confused manner in which they appear at such 

 vast distances, it was found necessary, by the ancient 

 astronomers, to class and arrange them under vari- 

 ous figures and resemblances, to which they gave the 

 names of several persons and things ; and these i 



