94 LATITUDE AND LONGITUDE. 



Here it is evident that, if at any given time when a 

 celestial body, such as the sun at S or a star at R was 

 on the meridian, we measured the angle SCZ, and 

 found the inferior limb of the sun was south of the 

 zenith, say 10 degrees 30 minutes, and that by the 

 tables, its declination on that meridian was 28 degrees 

 32 minutes, we should then have the value of the arcs 

 ES and GZ, which, added together, give the whole 

 arc EZ = the latitude = in degrees and parts of a 



degree EL. If we employed a star at R, and found it 

 north of the zenith, by some given arc ZR, and that it- 

 declination equalled the arc ER, then ER, ZR, or the 

 difference of those arcs, that is, EZ, equals the latitude 

 as before. Again, if the observation was made with a 

 star on the other side of the equator at M, after ascer- 

 taining the distance ZM, we should find the south 

 dedication EM ; here the declination and the zenith 

 distance being of the same denomination, we take the 

 difference of the arcs, and this also applies to any star 

 on the other side of the pole Pat B, ZM and^EM, 

 which gives ZM EM = LZ = the latitude. 



In finding the latitude this way by the stars, it is 

 not always necessary to know the longitude or the pre- 

 cise time of the observation, because their declination 



