20 Remarks on Ancient Eclipses. 



titv of tlie year not accurately known, proved the source of all the 

 errors of those and preceding times. The Julian year exceeded 

 the true measure by a certain unknown quantity, which in a 

 lapse of time so affected the calendars as to require them to un- 

 dergo new computations. Our countryman Roger Bacon, who 

 flourished in the thirteenth century, deserves to be introduced 

 on this occasion for his skill in astronomy, and the doctrine of 

 time at that period, since it plainly appears, that he not only 

 pointed out that error which occasioned the reformation of the 

 calendar that since gave such distinction about the old and new 

 style ; but also afforded a much more effectual and perfect re- 

 formation than that whieii was made in the time of Pope Gre- 

 gory XIII. This is abundantly illustrated in his book entitled Opus 

 Alajus, from whence we shall make only the following extract: 

 "Julius Caesar (says he, page 169) being well skilled in astro- 

 nomy, settled, as well as it was possible in his time, the calen- 

 dar : but Julius did not discover the exact length of the year; 

 for he has fixed it in our calendar at 365 days, and the fourth 

 part of a day, which fourth part is collected once in four years ; 

 so that in the bissextile year, one day more is reckoned in every 

 fourth year, than in the common years. It is however manifest, 

 not only by the old and new computations, but is also known 

 from astronomical observations, that the solar year is not that 

 length, but somewhat sliorter ; and this small difference wise men 

 have computed to be the 130tli part of a day, so that in the 

 space of 130 vears there is a superfluous day taken in, which if 

 it were taken away, our calendar would be corrected as to this 

 fault ; and therefore as in our computation all things depend 

 upon the quantity of the solar year, it is necessary to recede from 

 this position, when it thus appears to be a fundamental error. 

 From hence there arises still a greater error, that is, in fixing 

 the equinoxes and solstices ; and this error not only arises from 

 the quantity of the year, but has also several mischievous con- 

 sequences ; for the equinoxes and solstices are thereby fixed to 

 certain days, as if they were really upon them, and were so to 

 happen for ever. But it is certain from astronomy, which can- 

 not lie, that they ascend in the calendar, as by the help of tables 

 and instruments may be unquestionably proved." 



The Gregorian calendar, undertaken by Pope Gregory in 1582, 

 reformed on the aforesaid principles as nearly as possible the 

 errors of that which had obtained since the Council of Nice, 

 when it was found that the e()uinoxes and solstices had removed 

 ten whole days from their true places ; and that the ecclesiasti- 

 cal full moons had removed four or live days from their situation 

 in the calendar in the age of that council. 



The Correction of the Calendar : — The errors of the old ca- 

 lendar 



