ON INTRODUCED ANIMALS AND PLANTS. 155 



but gradually traverses all the seasons, and returns to the starting 

 point. If the length of the natural year was precisely three hundred 

 and sixty-five days and a quarter, the return would take place after 

 an interval of 1460 natural years, and of 1461 calendar years; for 



i- A x 1461=3651 days; and 

 365| d x 1460 = 533,265 days = 365 d x 1461; 



but the natural year being in reality somewhat shorter than 365i days, 

 the return will be proportionally delayed. 



An intelligent people would hardly fail to note the return and the 

 real interval. But in Egypt (where this calendar was once in vogue), 

 a peculiar circumstance tends to direct attention to these particulars : 

 for the summer solstice, taking place simultaneously with the com- 

 mencement of the inundation, regulates the agriculture* and the 

 whole business of the country. No other river, save the Nile, is punc- 

 tual to a day in its rise ; and in no other country, save Egypt, is there 

 an abrupt terrestrial mark of the termination of the natural year. 

 Were it yet possible for a community to overlook such manifest indi- 

 cations, the attention of the Ancient Egyptians was further arrested 

 by stated Sacred Festivals. 



The Egyptians used the calendar in question for many centuries, 

 and counted out the interval between the departure of their New Year 

 from the solstice and its return. Various ancient writers speak of the 

 Completion of the Egyptian Cycle ; and the date of this Completion 

 has formed the subject of inquiry, as an important point in Chronology. 



The length of this Cycle remaining uncertain, and believing, that 

 the experience of the Ancient Egyptians was somewhere recorded, I 

 proposed to myself a search; being aware (from Biot's computation), 

 that if our astronomical measurements of the year are correct, the 

 Cycle should consist of "1505 years:" 



Not long after this, I met with Manilius' account of the phoenix, 

 . . . " vivere annis DCLX. . . . Cum huius alitis vita magni conver- 

 sionem anni fieri prodidit idem Manilius, iterumque significationes 

 tempestatum et siderum easdem reverti : it lives six hundred and sixty 

 years : With the life of this bird, Manilius also relates, the revolving 

 of the Great Year comes to pass, and the signs of the seasons and stars 



* Mr. Grliddon informs me, that the Egyptian peasant, or "fellah," without regard to 

 any established calendar, ascertains seed-time by simply counting with his fingers the 

 number of days from "green water :" the name given to the initial day of the inundation. 



