70 The Earth considered as a Planet. 



may be necessary to make the reader ac- 

 quainted with the principle circles of the 

 globe, as they will greatly assist him in 

 comprehending those phenomena. 



This information he may attain suffi- 

 ciently for his present purpose in a quar- 

 ter of an hour, if he sets the ball of a ter- 

 restrial globe before him, or looks at the 

 figure of it, wherein these circles are 

 drawn and named. 



The Poles are the two extremities of 

 the earth's axis ; or those points where 

 the imaginary line, round which it per- 

 forms its daily revolutions, meets the 

 earth's surface ; that which is directed 

 towards the most northern point of the 

 heavens, being called the north pole ; and 

 that which is directed towards tke most 

 southern point, the south pole ; so that 

 they are di am e trie ally opposite to each 

 other, and always preserve the same rela- 

 tive situation. It is also to be observed, 

 that these two points have not been arbi- 

 trarily assumed by geographers and as- 

 tronomers, to answer their particular pur- 

 poses, as they are pointed out to us by 

 the nature and constitution of the globe, 

 and are easily distinguished from all 



