ITS EARLIEST STAGES. 143 



error of it by observing an eclipse of the moon 

 six years before the death of Alexander 25 . In this 

 corrected period, four cycles of 19 years were 

 taken, and a day left out at the end of the 76 

 years, in order to make allowance for the hours 

 by which, as already observed, 6940 days are 

 greater than 19 years, and than 235 lunations: 

 and this Calippic period is used in Ptolemy's Al- 

 magest, in stating observations of eclipses. 



The Metonic and Calippic periods undoubtedly 

 imply a very considerable degree of accuracy in the 

 knowledge which the astronomers, to whom they 

 are due, had of the length of the month ; and the 

 first is a very happy invention for bringing the 

 solar and lunar calendars into agreement. 



The Roman Calendar, from which our own is 

 derived, appears to have been a much less skilful 

 contrivance than the Greek ; though scholars are 

 not agreed on the subject of its construction, we 

 can hardly doubt that months, in this as in other 

 cases, were intended originally to have a reference 

 to the moon. In whatever manner the solar and 

 lunar motions were intended to be reconciled, the 

 attempt seems altogether to have failed, and to 

 have been soon abandoned. The Roman months, 

 both before and after the Julian correction, were 

 portions of the year, having no reference to full 

 and new moons ; and we, having adopted this divi- 

 sion of the year, have thus, in our common calen- 

 84 Delamb. A. A. p. 17- 



