THE SOURCE OF THE NILE. 413 



rent poftures, are ftill diflinctly to be feen upon the pedef- 

 tals everywhere among the ruins. 



It is not to be doubted, that hieroglyphics then, but not 

 aftronomy, were invented at Thebes, where the theory of 

 the dog-ftar was particularly inveftigated, becaufe connect- 

 ed with their rural year. Ptolemy* has preserved us an 

 obfervation of an helaical rifing of Sirius on the 4th day 

 after the fummer folflice, which anfwers to the 2250 year 

 before Chrift ; and there are great reafons to believe the 

 Thebans were good practical aftroilomers long before that 

 period f; early, as it may be thought, this gives to Thebes 

 a much greater antiquity than does the chronicle of Axum 

 jufl cited. 



As fuch obfervations were to be of fcrvice for ever, they 

 became more valuable and ui'eful in proportion to their 

 priority.' The moil ancient of them would be of ufe to the 

 aftronomers of this day, for Sir Ifaac Newton appeals to thefe 

 of Chiron the Centaur. Equations may indeed be difcover- 

 ed in a number of centuries, which, by reafon of the 

 fmallnefs of their quantities, may very probably have e- 

 fcaped the moil attentive and fcrupulous care of two or 

 three generations; and many alterations in the flarry fir- 

 mament, old ftars being nearly extinguilhed, and new e- 

 merging, would appear from a comparative ftate of the 



Y' 1 ' 3 r heavens 



* UranolotMon. P. Perau. 

 f Banbridge, Ann. canicuL 



