CALCULATION OF MEAN NEW AND FULL MOONS. 399 



of September, at 7 hours 40 minutes 8 seconds past LECT. 

 noon. One day too late, being after February in a v^-vx 

 leap-year. 



And thus may the mean time of any new or full moon 

 be found, in any year after the Christian ./Era. 



To find the mean time of new or full moon in any given 

 year and month before the Christian Mra. 



If the given year before the year of CHRIST 1. be 

 found in the third column of the table, under the title 

 Years before and after CHRIST, write it out, together 

 with the given month, and join the mean motions. But, 

 if the given year be not in the table, take out the next 

 greater one to it that you find ; which being still farther 

 back than the given year, add as many complete years 

 to it as will bring the time forward to the given year ; 

 then join the month, and proceed in all respects as 

 above. 



EXAMPLE in. 



Required the mean time of new moon in May, the year 

 before Christ, 585? 



The next greater year in the table is 600 ; which 

 being 15 years before the given year, add the mean 

 motion for 15 years to those of 600, together with 

 those for the beginning of May. 



Moon from sun. 



o 



To the year before Christ 600 . . . . 5 11 6 16 

 Add complete years motion 15 . . . . 6 55 24 

 And the mean motions for May . . . 22 53 23 



The whole sum is 4 55 3 



Which, being subt. from a circle, or . 12 



