IS On the Magnitude of the Year, 



Remark : "Astronomers having divided the interval of the se- 

 veral returns of the sun to the same colure, by the number of 

 revolutions, have found that the revokition was of 305 days 5'^ 

 48' 48", less by 20' than that observed in respect of the stars; 

 whence they have concluded, that each colure retrograded 49 

 or 50" every year. They have therefore called the Tropical 

 year, that whose revolution is of 365 days 5'' 49' ; and the Side- 

 real year, that which is made in 365 days 6'' 9 min." — La 

 Caille's Eleme7its, translated by Robertson, art. 471. 



The subjoined list is forwarded for insertion, if it will add to 

 the advantage of useful investigation ; and I wish, sir, some of 

 your able correspondents would furnish a like list of such various 

 measures of the solar, sidereal and lunar year, as have been de- 

 termined on by modern astronomers in England and other parts 

 of Europe. Sir, yours respectfully, 



T. Yeates. 



The various Magnitudes of the Year as determined by the an- 

 cient Astronomers . 



D. H. M. 

 Hermes Trismegistus, an ) An. an.Chr. 1480 365 



Egyptian astronomer . . S 

 Ennius, an Egyptian astronomer, An. an. Chr. 700 366 

 Thales the Milesian, a Grecian ) ^n. an. Chr. 620 365 



astronomer ) 



Oenepidus of Chios, a Grecian ^ An. an. Chr. 560 365 8 57 



astvonomer J 



Harpalus 



