to the tabular time, for every degree that the given place is eastward from WASHINGTON; or subtracting 4 minutes for every degree that the given place is west ward from WASHINGTON.

These Tables also begin the day at noon, and reckon forward to the noon following, for one day. Thus, March 31st. at 22 hours, 30 minutes, and 25 seconds of tabular time, (in common reckoning,) will be April 1st. at 30 minutes, 25 seconds after ten o'clock in the morning.

Interrogations for Section Thirteenth.

Does an object appear at a less angle when far off, than when near?

Do the Sun and Moon subtend different angles at different times?

Are the angles subtended by the Sun and Moon once at the greatest, and once at the least in one revolution? Are these gradual differences the same as they would be, if those luminaries moved in circular orbits?

Do they agree perfectly with elliptical orbits? Where must the lower focus of each orbit be placed to have them agree?

What is meant by the term apogee ?
What by perigee ?

Into how many parts do Astronomers divide each

orbit ?.

What is meant by the distance of the Sun or Moon from any point of its orbit?

What is the distance at any given point, of the Sun or Moon from its apogee called ?

What is the anomaly of the Sun or Moon when in apogee?

What in perigee ?

In what part of their orbits, are the Sun and Moon continually accelerated?

In what part retarded?

What are the mean motions of the Sun and Moon called?

What are the unequable called?

In what parts of their orbits are the mean motions forward of the true ?

In what part are the true forward of the mean? How many signs is the anomaly in the former case? How many in the latter?

Does the Moon's apogee move forward in the ecliptic? Does it move faster or slower than the Sun's?

Does the Moon revolve sooner from any node to the same again, than from any fixed star to the same again? If so, what is the difference?

What is meant by a lunation?

Why Do Astronomers begin the year with March? What does Table third contain? What Table first? Why was Table first calculated for Old Style?

What is the greatest difference between the mean or true time of new or full Moon, on account of the Sun's motion?

Are the lunations longer in winter than in summer? What reason can you advance? What the greatest difference? On what does these differences depend ? What are they called? Why is this equation not sufficient to reduce the mean time to the true?

Is the Moon's orbit more elliptical than the Sun's? What is meant by the word syzygy?

Is the Moon sometimes sooner or later in counjunction or opposition with the Sun, than she would be if her motions were equable in every part of her orbit ?

If so, what is the greatest difference? On what account does the Moon's orbit become different?

When is it the most eccentric? When the least? What is equal to the Sun's distance from the Moon's apogee? On what does the first of these differences depend? On what the second? What is the remotest point of the earth's orbit called ? What is the nearest point to the Sun called? Has the attraction of the earth any influence on the motion of the Moon ? In what case is the motion continually accelerated? what case retarded? Why is the Moon's orbit dilated in winter? Why contracted in summer? For what place are the following Tables calculated? means do they serve for any other place? At what time do the Tables commence the day?

In

By what

SECTION FOURTEENTH.

Precepts Relative to the following Tables.

To calculate the true time of new or full Moon, and Eclipses of the Sun or Moon, by the following Tables.

If the required new or full Moon be between the years 1800 and 1900, take out the mean time of new Moon in March, for the proposed year, from Table 16th together with the anomalies of the Sun and Moon, and the Sun's mean distance from the Moon's ascending node. But if the time of full Moon be required in March, add the half lunation at the bottom of the page, from Table 3, with its anomalies,&c. to the former numbers, if the new Moon falls before the 15th of March ; but if after the 15th of March, subtract the half lunation before mentioned, with the anomalies, &c. and write down the respective remainders.

In these additions and subtractions, observe that 60 seconds make a minute, 60 minutes make a degree, 30 degrees make a sign, and 12 signs a circle.

When the number of signs exceed 12 in addition, reject 12, and set down the remainder.

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When the number of signs to be subtracted is greater than the number you subtract from, add 12 signs to the minued, you will then have a remainder to set down.

When the required new, or full Moon is in any month after March, write out as many lunations, with their anomalies, and the Sun's distance from the Moon's ascending node from Table 3d. as the given month is after March, setting them regularly below the numbers taken out for March; add all these together, and they will give the mean time of the required new, or full Moon, with the mean anomalies, and the Sun's mean distance from the Moon's ascending node, which are the arguments for finding the proper equations

With the number of days of the sum; enter Table 4th under the given month, and against that number, you have the day of new, or full Moon in the left hand column; which set before the hours, minutes and seconds already found. But, (as it will sometimes happen,) if the said number of days fall short of any in the column, under the given month; add from Table 3d, one lunation, with its anomalies, &c. to the and aforesaid sum,

you will then have a new sum of days, wherewith to enter Table fourth, under the given month, where you are sure to find it the second time, if the first fails. With the signs and degrees of the Sun's anomaly, enter Table 7th, and therewith take out the annual, or first equation, for reducing the mean to the true syzygy; taking care to make proportions in the Table for the odd minutes of anomaly, as the Table gives the equation only for whole degrees.