THE USE OP THE CELESTIAL GLOBE. 325 



meet ; wbich divide the ecliptic into the 12 signs : but LECT. 

 if the star he on the south side of the ecliptic, place the ^ 

 90th degree of the quadrant on the south pole of the 

 ecliptic : keeping the 90th degree of the quadrant on the 

 proper pole, turn the quadrant about, until its graduated 

 edge cuts the star : then, the number of degrees in the 

 quadrant, between the eclip'tic and the star, is its lati- 

 tude ; and the degree of the ecliptic cut by the quadrant 

 is the star's longitude, reckoned according to the sign in 

 which the quadrant then is. 



PROBLEM III. 



To rep-esent the face of the starry firmament, as seen 

 from any given place of the earth, at any hour of the 

 night. 



Rectify the celestial globe for the given latitude, the 

 zenith, and sun's place, in every respect, as taught by 

 the 17th problem, for the terrestrial ; and turn it about, 

 until the index points to the given hour : then, the upper 

 hemisphere of the globe will represent the visible half 

 of the heaven for that time ; all the stars upon the globe 

 being then in such situations, as exactly correspond to 

 those in the heaven. And if the globe be placed duly 

 north and south, by means of a small sea-compass, every 

 star on the globe will point towards the like star in the 

 heaven : by which means, the constellations and re- 

 markable stars may be easily known. All those stars 

 which are in the eastern side of the horizon, are then 

 rising in the eastern side of the heaven ; all in the west- 

 ern, are setting in the western side ; and all those under 

 the upper part of the brazen meridian, between the 

 south point of the horizon and the north pole, are at their 

 greatest altitude, if the latitude of the place be north : 

 but if the latitude be south, those stars which lie under 

 the upper part of the meridian, between the north point 

 of the horizon and the south pole, are at their greatest 

 altitude. 



