same; but that a comet striking obliquely upon the earth gave it the diurnal revolution. He farther imagined that the antediluvian year consisted of 360 days, but that the additional matter deposited upon the earth from the atmosphere of the comet, at the time of the deluge, so retarded its revolution about the Sun, that it now requires 365 to complete the same.

This comet he thought would probably, by coming near the earth after being heated to an immense degree in its perihelion, be the instrumental cause of that great catastrophe, the general conflagration, foretold in the sacred writings.

The times of the Sun's rising and setting will be as follow:Thursday, Sunday, 11th, Wednesday, 21st, Saturday, 31st,

1st, Sun rises 56 m. past 7. Sun sets at 4m. past 4

5

-8

8

-8

5

55

3

3

3

Equation of Time.-The following table will point out the number of minutes and seconds that are to be subtracted from, or added to, the time shown on the dial, to obtain true or equal time for every fifth day of the month :

m. S.

1st, from the time on the dial SUBTRACT 10 49

The Sun enters Capricorn on the 22d, at 53 m. after 9 in the morning.

The Moon enters her last quarter on the 3d day, at, 45 m. past 3 o'clock in the morning. The new Moon, or change, occurs at 36 m. past 6 of the 11th she enters upon her first quarter on the 19th, at 5 m. past midnight; and is at the full on the 26th, at 11 o'clock precisely. The time of the Moon's rising for the first five days after the full, will be as follows:

On the 26th of December, the Moon, being at the full, will be eclipsed, visible at London :

Beginning of the eclipse will be 56 m. past 9

Middle

End

- 7}

181

Digits eclipsed 5° 50' on the Moon's north limb. On the 24th, the Moon will eclipse the star 18 8: the immersion will take place at 58 m. past 9 in the evening, and the emersion at exactly 11 o'clock. In the former case, the star will be 6' south of the Moon's centre; and in the latter, 10 on the same side.

On the 26th, the Moon will eclipse the star 8: the immersion will occur at 6 m. past 4 in the morning, and the emersion at 26 m. past 4; and, in both cases, the star will be 15' north of the Moon's centre.

Mercury is stationary on the 7th: on the 26th, Mercury will eclipse the star x; and, on the 30th, it will eclipse A. Mercury's greatest elongation will be on the 16th. The superior conjunction will be at 8 o'clock in the morning of the 26th. Jupiter will be in its quadrature on the 31st.

There will be visible at Greenwich, this month, three eclipses of Jupiter's first satellite, and two of the second, viz.

VIEW OF THE SOLAR SYSTEM.

Of the Georgian Planet, and of Comets.

This planet entirely escaped the attention and notice of antient astronomers. It was observed as a

small star by Flamstead, Mayer, and Le Mounier; but Dr. Herschel discovered its motion, and ascertained it to be a planet. Like Mars, Jupiter, and Saturn, it moves from west to east round the Sun. The duration of its sidereal revolution is 30,689 days, or about 84 years. Its motion, which is nearly in the plane of the ecliptic, begins to be retrograde before and after opposition, when the planet is 103°1 from the Sun; its retrograde motion continues 151 days, and the arc of retrogradation amounts to rather more than 3°. If we judge of the distance of this planet by the slowness of its motions, it ought to be at the very confines of the planetary system.

The apparent magnitude of this planet is so small, that it can seldom be seen with the naked eye... It is accompanied by six satellites. Its mean distance from the Sun is about 1,800,000,000 miles. Its diameter is 44 times larger than that of the earth, being more than 35,000 English miles. When seen from the earth, its apparent diameter, or the angle which it subtends at the eye, is 3" 32". As the distance of this planet from the Sun is twice as great as that of Saturn, its disk will appear four times smaller, and is but little the object of notice, except with those who possess good instruments. When, however, the sky is very serene and clear, it may be found with the naked eye; and it appears as a star of the sixth magnitude, with a bluish white light, and a brilliancy between that of Venus and the Moon; but, with a power of 200 or 300, the disk is visible, and very well defined.

The want of light, arising from the great distance of this planet from the Sun, is supplied by six satellites, all of which were discovered by Dr. Herschel. The first satellite revolves round its primary in 5 d. 21 h. 25 m.; the second, in 8 d. 17 h.; the third, in 10 d. 23 h.; the fourth, in 13 d. 11 h.; the fifth, in 38 d. 1 h. 49 m.; and the sixth requires to comH'h

plete its revolution nearly 108 days'. The second and fourth of these satellites were discovered on the 11th of January, 1787. The other four were discovered in 1790 and 1794; but their distances and periodic times, though set down above, are not so accurately ascertained as the other two. It is a remarkable circumstance, however, that all the six satellites move in a retrograde direction, and in orbits lying in or nearly in the same plane, and almost perpendicular to the ecliptic. La Place imagines that the first five satellites of the Georgian planet may be retained in their orbits by the action of the equator, and the sixth by the action of the interior satellites; and hence he concludes, that this planet revolves about an axis very little inclined to the ecliptic, and that the time of its diurnal rotation cannot be much less than that of Jupiter and Saturn.

The additions to our astronomical knowledge made by the discovery of this noble planet, and the other four smaller planetary bodies before described, as moving between Mars and Jupiter, do not merely present us with a few insulated facts similar to those with which we were formerly acquainted: They exhibit to us," says Mr. Brewster, 'new and unexpected phenomena, which destroy that harmony in the solar system which appeared in the magnitudes and distances of the planets, and in the form and position of the orbits. The six planets, which were formerly supposed to compose our system, were placed, excepting in the case of Mars and Jupiter, at somewhat regular distances from the Sun : they all moved from west to east, and at such intervals as to prevent any extraordinary derangements which might arise from their mutual action, Their magnitudes, too,

Dr. Herschel says, the eclipses of these satellites will be visible to the inhabitants of this planet in 1818, when they will appear to the observer to ascend through the shadow of the planet in a direction almost perpendicular to the ecliptic.

with the exception of Saturn, increased with their distance from the centre of the system; and the eccentricity, as well as the inclination, of their orbits, was comparatively small. In the system, as it is now understood and delineated by the most accurate ob servers, we find four very small planets between the orbits of Mars and Jupiter, placed at nearly the same distance from the Sun, and moving in very concen tric orbits which intersect each other, and are greatly inclined to the plane of the ecliptic. The satellites of the Georgian planet, likewise, move almost at right angles to the plane of the orbit; and, what is still more surprising, the direction of their motion is op posite to that in which all the other planets and planetary bodies, whether primary or secondary, circulate round their respective centres.

Comets are a class of celestial bodies which ap. pear occasionally in the heavens. They exhibit no visible or well defined disk, but shine with a pale and cloudy light, accompanied with a tail or train turned from the Sun. They are found in every part of the heavens, moving in all directions. When examined through a good telescope, a comet may be said to resemble a mass of aqueous vapours, encircling an opaque nucleus of different degrees of darkness in different comets, though sometimes no nucleus can be

seen.

As the comet advances towards the Sun, its faint and nebulous light becomes more brilliant, and its luminous train gradually increases in length.When it reaches its perihelion, the intensity of its light, and the length of its tail, reach their maximum, and sometimes it shines with all the splendour of the planet Venus. During its passage from the perihe lion, it is shorn of its splendour, it gradually resumes its nebulous appearance, and its tail decreases in magnitude, till it reaches such a distance from the earth, that the attenuated light of the Sun, which it reflects, ceases to reach the eye. Traversing unseen, by man, the remote portion of its orbit, the comet wheels its