OP DIALING. 395 



LECTURE XII. 



Shelving how to calculate the mean time of any New or Full 

 Moon, or Eclipse, from the creation of the world to the 

 year of CHRIST 5800. 



IN the following tables, the mean lunation is about a 

 20th part of a second of time longer than its measure as 

 now printed in the third edition of my Astronomy ; 

 which makes a difference of an hour and 30 minutes iu 

 8000 years. But this is not material, when only the 

 mean times are required. 



PRECEPTS. 



To Jind the mean time of any New or Full Moon in any 

 given year and month after the Christian jra. 



1. If the given year be found in the third column of 

 the Table of the moon's mean motion from the sun, under 

 the title* Years before and after CHRIST ; write out that 

 vear, with the mean motions belonging to it, and thereto 

 join the given month with its mean motions. But, if 

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

 lesser one to it that you find, in the same column ; and 

 thereto add as many complete yea*s, as will make up the 

 given year : then, join the given month, and all the re- 

 spective mean motions. 



2. Collect these mean motions into one sum of signs, 

 degrees, minutes, and seconds ; remembering, that 60 

 seconds (") make a minute, 60 minutes (') a degree, 30 

 degrees () a sign, and 12 signs (') a circle. When the 

 signs exceed 12, or 24, or 36 (which are whole circles) 

 reject them, and set down only the remainder ; which 

 together with the odd degrees, minutes, and seconds 



LECT. 

 XII. 



