DETERMINING THE LONGITUDE. 257 



Now, the assumed longitude is 6" : €1^ and 6'': H"*:— i 



6" ; 21" = nearly SS** : 50 at Greenwich. Sun's apparent > 15 : 30 : 06. 9 

 ARn. at Prome, at &" : 11"" : 22^ =(23 : 50 at Greenwich) is, ) - 



Right ascension moon's limb ... ... ... 21 : 41 : 29. 7 



Add moon's semidiameter in right ascension, 1 : 01. 1 



Riorht ascension moon's centre, ... ... ... 21: 42: 30. 8 



o 



iNow let us compare the moon's transit with that of the sun, on the fol- 

 lowing noon, and we must then reverse the operation, and take a mean of the 

 two observations. 



Moon's limb passed meridian on lyth, 6: 51: 55. 



Sun's ditto passed 18th, ... ... .., ,,. .„ 24: 40: 38. 8 



Interval, ... ... = ... ... .,. ... I7: 48: 43. 8 



XVate, ... ... ... ,ea ..a ,,, ~T~ ^ • 8 



Interval in mean solar time 17*. 48: 45. 6 



Daily acceleration, 12. 5, and correction for 17'': 48™. is, ... — 9. 4 



17: 48: 36. 2 



Complement, 6: 11: 23. 8 



Sun's right ascension as before, ... 15: 30: 06. 9 



Right ascension moon's limb, ... 21 : 41 : 30. 7 



Moon's semi-diameter, 1: 01. 1 



2 R 



