8 OUTLINES OF NATURAL PHILOSOPHY. 



Altitude or elevation of the pole above the hori- 

 zon of that place. 



14. The elevation of the pole at any place is 

 found, by observing one of the stars, which are 

 so near it as not to set, when it passes the meri- 

 dian above, and again when it passes the meri- 

 dian under the pole ; that is, by observing its 

 greatest and its least altitudes above the hori- 

 zon ; half the sum of the two altitudes of the 

 star, is the elevation of the pole, or the Latitude 

 of the place. 



For the star is always at the same distance 

 from the pole ; so that being on the meridian, it 

 was as much above the pole in the first observa- 

 tion, as it was below in the second. 



a. Those stars never set at any place of which the 

 polar distance is equal to the latitude of the place. 



b. This observation requires the use of an instrument 

 which can be placed accurately in the plane of the 

 meridian, such as the Astronomical Circle, the 

 Quadrant, &c. or one like HADLEY'S Sextant, 

 which can determine the greatest or least altitude 

 of a star above the horizon, without any previous 

 inquiry into the position of the meridian. 



15. To 



