THE SOURCE OF THE NILE. 15$ 



On the day of the furamer folfticc, at the moment the 

 fun was ftationary in the meridian of Syene, he placed a ityle 

 perpendicularly in the bottom of a half- concave fphcre, 

 which he expofed in open air to the fun at Alexandria. Now, 

 if that ityle had call no fhade at Alexandria, it would have 

 been precifely in the fame circumilance with a ityle in the 

 well in Syene ; and the reafon of its not calling the made 

 would have been, that the fun was directly vertical to it. 

 But he found, on the contrary, this ityle at Alexandria did 

 call: afliadow ; and by meafuring the diftance of the top of 

 this fhadow from the foot of the ftyle, he found, that, when 

 the fun call: no fhadow at Syene, by being in the zenith, at'. 

 Alexandria he projected a fhadow ; which fhewed he was 

 diflant from the vertical point, or zenith, j±o = j° I2 ^ which 

 was y^th of the circumference of the whole heavens, or of. 

 a great circle. 



This being fettled, the conclufion was, that Alexandria 

 and Syene muft be diftantfrom each other by the 50th part'-. 

 of the circumference of the whole earth. 



Now 5000 ftades was the diftance already affumed be- 

 tween Alexandria and the well of Syene ; and all that was 

 to be done was to repeat 5000 ftades fifty times, or multiply 

 5,000 Hades by 50, and the anfwer was 250,000 ftades, which 

 was the total of the earth's circumference. This, admitting 

 the French contents of the Egyptian ftadium to be juft, will 

 amount to 1 1,403 leagues for the circumference of the earth 

 fought ; and as our prefent account fixes it to be 9000, 

 the error will be 2403 leagues in excefs, or more than one- 

 fourth of the whole fum required. 



This 



