COMMON THINGS TIME. 



THE interval between two successive conjunctions of the moon 

 with the sun, or between two successive new moons, is greater 

 than the moon's period. If we suppose the sun and moon to start 

 together from conjunction, the moon moving more than thirteen 

 times faster, immediately goes before the sun; and- as the sun 

 moves at the rate of about 1 per day, the moon must move at the 

 rate of more than 13 per day, and consequently departs from the 

 sun at the rate of more than 12 per day. When the moon has 

 made a complete revolution, that is at the end of 27*32166 days 

 from conjunction, the sun will have advanced about 27 from the 

 place at which the moon arrives after having completed its revo- 

 lution. The next conjunction or new moon cannot take place 

 therefore until the moon overtakes the sun, and as it advances upon 

 the sun at the rate of a little more than 12 per day, it will tako 

 somewhat more than two days to come up with it. In fine, by 

 the most exact observations and calculations, it has been found 

 that the interval between two successive conjunctions is 



29-530589 days 

 expressed decimally, or in hours, minutes, and seconds 



29 d 12 h 44 m 2-89 s . 



This interval is called a LUNATION, and it exceeds 29| days, as it 

 appears, by a little less than three quarters of an hour. 



Although the lunation is not commensurable with either ths 

 day or the year, yet its recurrence, and even its fractional parts, 

 are marked by phenomena so striking and so universally observable 

 without instruments, that in all ages and all countries it has by 

 common consent been used to measure time, the fractional parts 

 by which it exceeds 29 and falls short of 30 days, being com- 

 pensated by various expedients. 



The evident object to which the adoption of months was directed 

 was to establish a convenient chronometric unit, holding an inter- 

 mediate place between the week and the year ; such unit to consist 

 of a complete number of days without a fraction, and to be at the 

 same time an exact submultiple of the year ; that is, such an 

 interval that the year should be an exact multiple of it, and finally 

 that it should be in as near accordance as might be found prac- 

 ticable with the period of the lunar changes. 



That various nations in different ages should be found incomplete 

 disaccord in their attempts at the satisfaction of these several con- 

 ditions, and that the usages and chronological forms into which 

 these attempts resolved themselves should exhibit much confusion, 

 will not be at all surprising when it is considered that the condi- 

 tions themselves are not only incompatible one with another, but 

 their satisfaction utterly impracticable. 



These conditions involve the consideration of three distinct 

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