used by the Ancient Egyptians. 163 



which even ChampoUion, who was disposed to give the highest possible antiquity 

 to them all, could refer -to an earlier age than the twenty-first century before our 

 era. Is it probable that the hieroglyphic calendar should have been in use for 

 twelve centuries before that time, and that no monumental records of its exist- 

 ence should remain ? But I will rather apply myself to expose the fallacy of the 

 grand argument, by which they, who throw back the origin of the hieroglyphic 

 . calendar to 3285 B. C, or before it, pretend to establish their system. 



This argument may be briefly stated as follows. There is reason to think, 

 from certain passages in ancient authors^ that the summer solstice and the heliacal 

 rising of Sirius coincided at the time when the hieroglyphic calendar was con- 

 structed. M. Biot alleges that this coincidence took place in the year 3285 

 B. C. ; and, though he admits that it would continue sensibly, or within the 

 limits of errors of observation, for 500 years on either side of this epoch, that is, 

 from 3785 to 2785, he seems to think we are tied down to the middle date by 

 the consideration that then only the two coincident phenomena would occur at 

 the beginning of the ninth month of the wandering year. Now I admit that it is 

 probable, though it is by no means certain, that there was a sensible coincidence 

 between the summer solstice, the heliacal rising of Sirius, and the 241st day of 

 the Egyptian year, when the hieroglyphic notation was introduced ; but I say 

 that this coincidence might have occurred more than 1000 years after the epoch, 

 which M. Biot has assigned for it, and subsequent to the biblical epoch of the 

 colonization of Egypt. 



In order to prove this, I chiefly insist on the points, that what is called the 

 heliacal rising of a star depends on two uncertain elements, namely, the latitude 

 of the place of observation, and the depression of the sun below the horizon at 

 the time of the star's rising, which is barely sufficient to allow that star to be 

 seen ;* that M. Biot has assumed greater values for both these elements than he 



* In order to determine the heliacal rising of a star, spherical trigonometry furnishes us with the 

 following formulas : a being the latitude of the place of observation ; y the depression of the sun 

 below the horizon necessary for the star's being seen at its rising ; X being the declination, and ^ 

 the right ascension of the star, and ui being the obliquity of the ecliptic ; we have, the latitude being 

 north, and the decUnation of Sirius south ; 



tan. a. tan. A, zr sin. y; 



X 2 



