Unpublished Writing. 201 



The commencement of that cycle is placed by ancient 

 chronologers in 1322 A.C. It seems not correct to call 

 2782 A.C. " the earliest epoch of Egyptian chronology," 

 for we have none of their chronology nearly so old, and 

 in fact no chronology, properly so called, has yet been 

 made out by our Egyptian researches. It is indeed cer- 

 tain that, if the reckoning by heliacal risings of Sirius did 

 not begin in 1322, we must go nearly 1460 years back for 

 its origin ; since it must have been adopted when that 

 event preceded only for a short time the annual inunda- 

 tion of the Nile. But, according to some, the year 1322 

 A.C. fell during the reign of Sesostris, to whom Herodotus 

 ascribes several regulations connected with the rising of 

 the Nile. Certainly, 2782 A.C. is a more remote era than 

 we are hitherto warranted to assume for any astronomical 

 observation. 



Believe me, dear Mrs. Somerville, 



Very truly yours, 



HENRY HALLAM. 



I refer you to Montucla, if you have any doubt about 

 the Egyptian year being of 365 days without bissextile of 

 any kind. 



I had sent a copy of the " Mechanism of the 

 Heavens" to M. Poisson soon. after it was published, 

 and I had received a letter from him dated 30th 

 May, 1832, advising me to complete the work by 

 writing a volume on the form and rotation of the 

 earth and planets. Being again strongly advised to 



