ASTRONOMY. 7 



c. If a vertical circle pass through a star, (or any 

 point in the heavens), the arch of that circle inter- 

 cepted between the star and the horizon is called 

 the Altitude of the star ; and the arch of the hori- 

 zon intercepted between the said vertical and the 

 meridian is called the Azimuth of the star. 



d. Vertical Circles are also called Circles of Azimuth. 



e. The altitude of a star above the horizon, is great- 

 est when it is on the meridian ; and a star has e- 

 qual altitudes when it is at equal distances from 

 the meridian on either side, or when its eastern 

 and western azimuths are equal. 



11. All the circles hitherto defined, are deter- 

 mined in their position, either by the diurnal 

 motion of the heavens, or by the direction of 

 gravity. 



12. If a meridian circle pass through any star, 

 trie arch of that circle intercepted between the 

 star and the Equator is called the Decimation 

 of the star ; and if it pass through the zenith of 

 any place, the arch intercepted between that zer 

 nith and the equator is called the Latitude of 

 the place. 



13. The Latitude of any place is equal to the 



altitude 



