156 CHRONOLOGICAL OBSERVATIONS 



again return" (Pliny x. 2). Now, a period of 660 years does not 

 agree with the return of the stars and seasons : but a question arose, 

 Might not this period have formed a division of the Great Year? 

 2i phoenixes fell below the mark; 2i far exceeded it; 21 gave 1540 

 years, which was a possible number. I was now to apply a test; 

 derived from an opinion I had formed, that the Egyptian Cycle was 

 some multiple of 7. The test appeared to fail in the instance of 660; 

 but 1540 years proved to be divisible by 7 ; and when so divided, gave 

 i of a phoenix. 



I was no longer in doubt, as to the experience of the Ancient Egyp- 

 tians : and when I had nearly finished printing my work on the Races 

 of Man, an opportunity offered of introducing the subject. It seemed 

 however to be going out of my way, and I had nearly decided in the 

 negative ; in a moment of perplexity seeking to divert my thoughts, I 

 took up Fisher's "Dial of the Seasons," a volume chance had placed 

 upon my table. Turning over the leaves, my eye rested on the page 

 treating of the velocity of light; and I perceived, that the time assigned 

 for the passage of light from the sun, was the amount wanting to 

 reconcile the astronomical and Egyptian measurements of the Great 

 Year. Here, was confirmation of a count by the Egyptians ; but the 

 accompanying result was unlooked for. 



The next step was, to determine with more precision the annual 

 difference. Roemer (as quoted in Herschel's Outlines of Astronomy, 

 545), assigns 8 m 133 s for the passage of light across half the diameter 

 of the earth's orbit. Keeping this in view, I proceeded at first by 

 rough approximations : as 



1505 yre 1540 5 ' re 365i diys 



1460 1505 365 5 h 48 m 49-7' (Solar year, Baily, quoted by Herschel, 383). 



~^5 :~ 35 :7 Tl 10-3 : 8 m 41-3' 



1460 y " : £*» : : 1540 yrs : 379 m 434]° (exceeding i (1 +H m 10-3% by 8 m 33-2 s ). 

 1461 yrs . i6,j . . 1540 yrs . 379™ 27|g^ s (exceeding the same, by 8 m 17-6 S ). 



The results obtained by the above approximations are all too large ; 

 for 



365! d — 7 y = 365 3 V g = 3 7 oV X 1541 ; and 

 3653 7 oV X 1540 = 562,465 days = 365 d x 1541 ; 



or in other words, If the natural year were 7 1 ? d shorter than 365 i days, 

 the return would take place at the end of 1540 natural years, of 1541 



