OF THE CELESTIAL GLOBE. 327 



LECT. 



X. 

 PROBLEM VI. v^,-* 



The latitude, day of the month, and azimuth 9 * of any 

 known star being given ; to find the hour of the night. 



Having recti6ed the globe for the latitude, zenith, and 

 sun's place : lay the quadrant of altitude to the given 

 degree of azimuth in the horizon; then turn the globe on 

 its axis, until the star comes to the graduated edge of 

 the quadrant ; and when it does, the index will point out 

 the hour of the night. 



PROBLEM VII. 



T/te latitude of the place, the day of the month, and 

 altitude" of any known star, being given ; to find the 

 hour of the night. 



Rectify the globe as in the former problem, guess at 

 the hour of the night, and turn the globe until the index 

 points at the supposed hour ; then lay the graduated 

 edge of the quadrant of altitude over the known star, 

 and if the degree of the star's height in the quadrant 

 upon the globe, answers exactly to the degree of the 

 star's observed altitude in the heaven, you have guessed 

 exactly : but if the star on the globe is higher or lower 

 than it was observed to be in the heaven, turn the globe 

 backwards or forwards, keeping the edge of the quad- 

 rant upon the star, until its center comes to the ob- 

 served altitude in the quadrant; and then, the index will 

 shew the true time of the night. 



Note 98. The number of the degrees that the san, moon, or any 

 star, is from the meridian, either to the east or west, is called its 

 azimuth. Note by the .-Luther^ 



Note 99. The number of degrees that the star is above the hori- 

 zon, as observed by means of a common quadrant, is called its 

 altitude. Ibid. 



