362 Mr. RoTHMAN on an Ancient 



Vol. I. p. 355.) or " at Alexandria, the gnomon has the same ratio 

 to the equinoxial shadow that 5 has to 7." 



Now 



log. 7 = 0.8450980 



log. 5 = 0.6989700 



log. tan. 2 = O.146128O 



(where z = zenith distance observed,) 



.-. z = 54". 27'. 45" 



Refraction ^ . 1 . 19 



Parallax = -0.0.6 



54.28.58 

 \ Sun's diameter = O. 15.58 



Corrected zenith distance = 58.44.56 



Now by modern observations the latitude of Alexandria is 

 .n".i3'.5". Vide positions given in Tables du Bureau des Longi- 

 tudes, Tab. I. Adding then to our corrected zenith distance the 

 co-latitude of the place, we shall soon see, that the zenith dis- 

 tance in question evidently corresponds to the winter solstice: 

 for 



Co-latitude of Alexandria = 58°. 46'. 55" 



Zenith distance of Sun = 54.44.56 



Sum = 113.31.51 



90 . 0. o 



23 .31 .51 



If we subtract from the sum 90° we find the Sun to the 

 southward of the equator 23°. 31. 5 1": which proves clearly the 

 observation to have been made at the winter solstice. 



