ARTIFICIAL HORIZONS, &C. 329 



Add the cojine of the angle from noon, to the cotan- 

 gent of the declination ; the fum is the cotangent of an 

 arch A. 



Add the fine of A, the fine of the altitude, and the 

 arithmetical complement of the fine of the declination^ 

 together ; the fum is the cojine of an arch B. 



Then the fum or difference of A and B is the latitude. 



As every fingle altitude gives an independent lati- 

 tude, it is evident the latitude may be thus found to 

 great exa&nefs. 



An inftrument might eafily be contrived to meafure 

 the fun's angle of pofition to great exa&nefs, from 

 whence the latitude might readily be deduced; a fmali 

 addition to the common theodolite would be fufficient. 

 The variation of the azimuth near the meridian may 

 alfo be advantageoufly applied for the fame purpofe. 



Vol. I. A a DEMON- 



