I! S'TIIODI VTION. 



spore hazy, with almost constant cirrus clouds. The alt-azimuth instrument was placed within 

 three feet of the collirnator magnet. 



Observations for magnetic meridian. 



Observations for true meridian. 



The latitude of the station, time of observation, and polar distance of the sun or a star being 

 known, its true azimuth is readily computed by the following formulas : 



cos (T: 

 sin $ (TT 



sm i (- -f- (p) 



in which 



A represents the true azimuth counted from north. 



V the angle at the sun or star. 



P the hour angle at the pole. 



T the polar distance of the sun or star. 



<p the co-latitude of the place of observation. 



