Age of the world uncertain.
By the method prescribed § [248] it will be found, that the Autumnal Equinox in the year before Christ 4030, fell on the 26th of October; as this Example shews the Full Moon to have been on the same day: and by working as hereafter taught, it will appear that the Dominical Letter was then G, which shews the 26th of that October to have been on a Friday; namely our sixth day of the week, but the Ante-Mosaic fifth day. And as, according to Genesis, chap. i. ver. 14. the Sun and Moon were created on the fourth day of the week, those who are of opinion that the world was made at the time of the Autumnal Equinox, and that the Moon at her first appearance was in full lustre, opposite to the Sun, or nearly so, may perhaps look upon this as a Criterion for ascertaining the year of the creation; since it shews the Moon to have been Full the next day after she was made: and this is only 9 years sooner than Rheinholt makes it, and 11 years later than according to Lange. Whereas, they who maintain that the world was created in the 4007th year before Christ, with the Sun on the Autumnal Equinoctial Point, October 26, and the Moon then Full; will find, if they compute by the best Tables extant, that the Moon was New, instead of being Full, on that day.
If it could be proved from the writings of Moses that the Sun was created on the point of the Autumnal Equinox, and the Moon in opposition; as well as it can be proved that these Luminaries were made (or according to some, did not shine out till) on the fourth day of the creation-week, there would be Data enough for ascertaining the age of the world: for supposing the Moon to have been Full on an Equinoctial Day, which was the fourth day of the week, it would require many thousands of years to bring these three characters together again. For, the soonest in which the Moon returns to be New or Full on the same days of the Months as before, is 19 years wanting an hour and half, but then the days of the week return not to the same days of the months in less than 28 years, in which time the Moon has gone through one Course of Lunations, and 9 years over; therefore a co-incidence of the Full Moon and day of the Week and Month cannot happen in that time, and if we multiply 19 by 28, which is the nearest co-incidence of these three characters, namely 532 years; the Moon’s falling back an hour and half every 19 years will amount to 42 hours in so many years; and the Equinox will have anticipated five days. From all which we may venture to say, that 200000 years would not be sufficient to bring all these circumstances together again.
EXAMPLE III.
To find the time of Full Moon at Babylon in March, the year before Christ 721.
The years 720 added to 1780 make 2500, or 25 Centuries.
| Days | Hours | Min. | Sun’s Anom. | Moon’s Ano. | |||||
|---|---|---|---|---|---|---|---|---|---|
| s | ° | ʹ | s | ° | ʹ | ||||
| Tab. I. To the mean F. Moon and Anom. in Mar. 1780 | 9 | 4 | 41 | 8 | 19 | 48 | 7 | 8 | 10 |
| Add one Lunation and it’s Anomalies from Tab. VI[[80]] | 29 | 12 | 44 | 0 | 29 | 6 | 0 | 25 | 49 |
| The several sums are | 38 | 17 | 25 | 9 | 18 | 54 | 8 | 3 | 59 |
| Fr. which subt. the Days & Anom. of 2500 years, Tab. V | 19 | 22 | 20 | 11 | 26 | 19 | 6 | 6 | 43 |
| Rem. the mean time and Anom. of F.M. in Mar. b.C. 721 | 18 | 19 | 5 | 9 | 22 | 25 | 1 | 27 | 16 |
| To which add the sum of the three Equations | + | 11 | 36 | Equ. Moon’s Anom. | - | 18 | |||
| And it gives the true time of Full Moon, Mar. b.C. 721 | 18 | 6 | 41 | Anom. cor. | 1 | 26 | 48 | ||
| Sun’s Equat. | + | 1 | 47 | ||||||
| Which was the 19th day, at 41 minutes past 6 in the evening, at London; to which time, if[[81]] 2 hours 51 minutes be added, we shall have the time at Babylon, namely, 9 hours 51 minutes. | Moon’s Anom. | 1 | 28 | 35 | |||||
| Moon’s ann. Eq. | 0h | 20m | add | ||||||
| Her ellipt. Equ. | 8 | 1 | add | ||||||
| Sun’s Equation | 3 | 15 | add | ||||||
| Sum | 11 | 36 | add | ||||||
357. To know whether the Sun will be eclipsed or no, at the time of any given New Moon; collect the Sun’s distance from the Node at that time, and if it be less than 17 degrees he will be eclipsed, otherwise not.
EXAMPLE.
For the time of New Moon in April 1764.
| Sun from Node | |||
|---|---|---|---|
| s | ° | ʹ | |
| Table II, mean New Moon in March 1764, New Stile, | 11 | 4 | 57 |
| Table VI, add for 1 Lunation to carry it to April | 1 | 0 | 40 |
| Sun’s distance from the Node at New Moon in April | 0 | 5 | 37 |
Which, being within the above limit, the Sun must be eclipsed: and therefore, we proceed to find the rest of the Elements for computing this Eclipse.