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The daily revolution of the Earth, which is known to be uniform, is always completed, when any particular meridian is exactly parallel to the situation which it had at a certain time of the preceding day. For the same meridian can never be brought round from the Sun to the Sun again, by one entire revolution of the Earth upon its axis, but it will require as much more of another revolution, as is equivalent to the space that the Earth has advanced in its orbit during that time; which is, at a medium, the 365th part of a circle. So that in 365 days, the Earth will have turned 366 times round its axis; and therefore as one complete rotation makes a Sidereal day, in a year there will be one more sidereal day than there are solar days, be that number what it may.
It may be observed, that the regular return of the fixed stars to the meridian affords an easy method of determining whether our chronometers keep true time. For if through a small hole in a window-shutter, or other fixed object, it be observed at what time a given star disappears behind any building at a small distance; then if the same star disappears the next night, 3m. 56s. sooner by the clock or watch, than it did the night before, and on the second night 7m. 52s. sooner, and so on, it-is a proof that the instrument goes right; but if it does not observe this rule, it is evidently not accurate, and requires to be regulated. As the disappearing of a star is instantaneous, this rule may be depended on to half a second.
The following are the times of Sun-rising and setting, at London, for this month:
1st. Sun rises 27m. past 7. Sun sets 33m. past 4.
Equation of Time.—[See the month of January.]
The following table will show what is to be added to the time pointed out on the dial, to obtain true or equal time for every 5th day of February: Tuesday, Feb. I, to the time on the dial add 13m. 56s.? Sunday, 6,
14 26 Friday,
14 35 Wednesday, 16,
14 26 Monday,
13 59 Saturday, - 26,
To obtain true time by the clock.
The Sun enters Pisces on the 19th, at 20m. past 5 o'clock in the morning. Venus appears stationary on the 18th.
The Moon is full on the 4th, at 46m. past 6 in the afternoon : it enters its last quarter on the 12th, at 45m. past 4 in the morning ; the preceding new moon is at ilm. past 7 in the morning of the 20th, and it enters its first quarter at 26m. past 10 in the morning of the 27th. The time of the Moon's rising, for the first five days after she is full, will be as follows, viz. on the
5th of February, 34m. past 5 in the afternoon.
6 ditto, 7th
8 ditto. 8th
9 ditto. 9th
10 ditto. On the first day of this month the Moon will eclipse the star inarked v II. in astronomical catalogues. The immersion will take place, at 13m. past 11 in the evening, when the star will be 7m. south of the Moon's center; and the emersion will be at 13m. past 12, the star being 8m. south of the Moon's centre,
On the 12th day, the Moon will eclipse the star v.. The immersion will happen at 8m. past 12 in the morning, when the star is 7m. north of the Moon's centre; and the emersion will take place at 16m. past 3 in the morning, the star being 10m. north of the Moon's centre.
At 20m. past 5 in the morning of the 18th, Mercury will be in conjunction with the Sun. On the 24th, at 9 in the morning, Jupiter will be in opposition to that luminary.
The eclipses of Jupiter's first satellite, for February, that are visible, in London and its vicinity, are as follow, viz. the immersions take place on the
3d day, at 42m. past 2 o'clock in the morning.
OF THE COMET, IN 1811.
By Charles Verral.*
[Author of the “ Pleasures of Possession."]
Ar midnight, through the fields of air,
* This gentleman, whose former production has received its tribute of approbation, amongst all readers possessed of unvitiated taste,-who prefer the sterling simplicity aad sweetness of Goldsmith, Campbell, and Rogers, to the insipid doggerel, that, under various titles of tales and bat. tles, bas of late dishonoured the English language, and not seldom the genius of the writers themselves, is about to publish a volume of poems, which will contain some dramatic pieces, that, we have no doubt, will increase his reputation as a Poet.Ed.
And see the ill-omen'd Comet trail Amid the stars, his fiery tail ! Portentous beam! thou rid'st sublime, Still as the silent tread of time; But fatal to mankind below, As the loud thunder's deadliest blow : Thy solemn march, thy dismal light, Fill gazing nations with affright; And tell a tale as dire and dread As ghosts that haunt the murderer's bed. Wroth at our crimes, the Eternal Sire Launch'd in mid-air thy world of fire, Mark'd out thy course, and bade thee bring Strange terrors on thy flaming wing: Oft as thy wandering orh returns, With threefold heat, the dog-star burns; With threefold rage November blows; Threefold December heaps his snows; And streams and floods in threefold chains, Stern Winter's icy band restrains.
Oh! could'st thou quit thy custom'd way,
But he, who angry at our crimes,
To light his victims to their tomb,
grace with awful pomp their doom :
Eclipses were formerly subjects of dread and terror; but philosophers have converted them to the purposes of utility and instruction. The Moon can only be eclipsed by the interposition of an opaque body, which intercepts from it the light of the Sun; and it is obvious that this opaque body is the Earth, because the eclipses of the Moon never happen, except when the Moon is in opposition, and consequently when the Earth is interposed between her and the Sun. The globe of the Earth projects behind it a conical shadow, the axis of which is the straight line that joins the centres of the Earth and Sun, and which terminates at the point where the apparent diameters of these two bodies become equal. The di, ameters of these two bodies, seen from the centre of the Moon in opposition, are nearly in the proportion of 3 for the Sun, and 11 for the Earth. Therefore the conical shadow of