322 FERGUSON'S LECTURES. 



in that semicircle of it which cuts the ecliptic at 

 the beginning of Aries nr ; and thence eastward, quite 

 round, to the same semicircle again. Consequently 

 those stars which lie between the equinoctial and the 

 northern half of the ecliptic, have north declination and 

 south latitude ; those which lie between the equinoctial 

 and the southern half of the ecliptic, have south declina- 

 tion and north latitude ; and all those which lie between 

 the tropics and poles, have their declinations and lati- 

 tudes of the same denomination. There are six great 

 circles on the celestial globe, which cut the ecliptic per- 

 pendicularly, and meet in two opposite points in the 

 polar circles ; which points are each ninety degrees from 

 the ecliptic, and are called its poles. These polar points 

 divide those circles into 12 semicircles ; which cut the 

 ecliptic at the beginnings of the 12 signs. They re- 

 semble so many meridians on the terrestrial globe ; and 

 as all places which lie under any particular meridian 

 semicircle on that globe, have the same longitude, so all 

 those points of the heaven, through which any one of 

 the above semicircles are drawn, have the same longi- 

 tude. And as the greatest latitudes on the earth are at 

 the north and south poles of the earth, so the greatest 

 latitudes in the heaven, are at the north and south poles 

 of the ecliptic. 



Constella- In order to distinguish the stars, with regard to their 

 situations and positions in the heaven, the ancients di- 

 vided the whole visible firmament of stars into particular 

 systems, which they called constellations ; and digested 

 them into the forms of such animals as are delineated 

 upon the celestial globe. And those stars which lie be- 

 tween the figures of those imaginary animals, and could 



world (which are two opposite points, each 90 degrees from the equi- 

 Colures. noctial,) is called the equinoctial colure : and the great circle that passes 

 rtrongh the beginning of Taurus and Libra, and also through the poles 

 of the eciiftic, and poles of the world, is called the solstitial colure. 



