NATURAL HISTORY. 



their relative situation, magnitude, distances, 

 motions, and eclipses. To determine these points, 

 has been distinguished by the appellation of pure 

 or plain astronomy. To investigate the causes of 

 their motion, arid the laws by which they are 

 governed, comes under the head of physical 

 astronomy. 



The appearances of the heavenly bodies were 

 calculated to excite the earliest attention of man- 

 kind. We accordingly find, that the ancient 

 shepherds, from residing in a climate in which 

 the brilliancy of the nights and the serenity of 

 the atmosphere' invited them to make observa- 

 tions, very soon began to mark down in their 

 memories the various constellations ; and by the 

 aid of the imagination, to compare them to some 

 animal or other substance to which they conceived 

 they bore a resemblance, and named them accord- 

 ingly; and having ascertained that the courses 

 of the different constellations were apparently 

 from east to west, according to their relative 

 situation, they soon learned to make their move- 

 ments subservient to the purposes of travelling 

 by sea and by land, no other guide or rule having 

 at that period presented itself. 



Thus was laid the foundation of one important 

 part of astronomy, which has been continued up 

 to the present day; namely, the different appear- 

 ances and relative situation of the heavenly con- 

 stellations. But in the infancy of human know- 



