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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. 4th - ll 9 - - evening. 10th, —
- morning. 11th - 5 – 11 - - evening.. 18th – 58 – 12 - - evening. 20th – 26 – 7
- evening. 26th
- morning 27th – 35 - 11
OF THE COMET, IN 1811.
By Charles Verral.*
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, has 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 orb 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,
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 dis 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 the Earth is, at least, thrice as long as the distance between the Earth and Moon, and its breadth at the point where it is traversed by the Moon more than double the diameter of that
luminary. The Moon, therefore, would be eclipsed every · time it is in opposition, if the plane of the orbit coincided
with the ecliptic. But in consequence of the mutual incli nation of these two planes, the Moon, when in opposition, is often elevated above the Earth's shadow, or depressed below it, and never can pass through that shadow, unless when it is near the nodes. If the whole of the Moon's disk plunges into the shadow, the eclipse is said to be total; if only a part of the disk enter the shadow, the eclipse is said to be
The Moon's diameter, as well as the Sun's, is supposed to be divided into 12 equal parts, called digits; and so many of these parts as are darkened by the Earth's shadow, so many digits is the Moon said to be eclipsed. All that the Moon is eclipsed above 12 digits shews how far the shadow of the Earth is over the body of the Moon, on that edge to which she is nearest at the middle of the eclipse.
Eclipses of the Sun only take place during the conjunctions of the Sun and Moon: they are occasioned by the Moon's body being interposed between the Sun and Earth, or, in other words, by the Earth's being plunged in the shadow of the Moon. The Moon, though much smaller than the Sun, is so much nearer to the Earth, that its apparent diameter does not differ much from the diameter of that luminary; and, in consequence of the changes which take place in the apparent diameter of these bodies, it happens that, in some positions, the apparent diameter of the Moon is greater than that of the Sun. If we suppose the centres of the Sun and Moon in the same straight line with the eye of the spectator placed on the Earth, he will see the Sun eclipsed. If the apparent diameter of the Moon happens to surpass that of the Sun, the eclipse will be total; but if the Moon's din
ameter be the smallest, the observer, if properly situated, will see aluminous ring formed by that of the Sun's disk, which exceeds that of the Moon's; and the eclipse, in this case, is called annular. If the centre of the Moon is not in the same straight line which joins the observer and the centre of the Sun, the eclipse can hardly be partial, as the Moon can only conceal a part of the Sun's disk: on these accounts, there must necessarily be a great variety in the appearances of solar eclipses. We may add also, to these causes of variety, the elevation of the Moon above the horizon, which is the cause of considerable changes in the diameter; for it is a fact, well and generally known, that the Moon's diameter appears larger when she is nearer the horizon than when she is elevated above it: and, as the Moon's height above the horizon varies according to the longitude of the observer, it follows, that the solar eclipses will not have the same appearance to observers situated in different longitudes on the earth. One observer may see an eclipse which does not happen to another in a different situation, and yet the latter as well as the former shall be above the horizon in the same hemisphere; and, in this respect, the solar differ from the lunar eclipses, which are the same to all the inhabitants of the earth. We often see, says La Place, the shadow of a cloud transported by the winds, rapidly pass over the hills and vallies, depriving those spectators which it reaches of the light of the Sun that others are enjoying ; this is the exact image of a total eclipse of the Sun. A profound night, which, under favourable circumstances, may last from four to five minutes, accompanies these eclipses; the sudden disappearance of the Sun, with the solemn darkness that succeeds, fills all animals with dread; the stars which have been effaced by the light of the day, show themselves in full lustre, and the heaven resembles the most profound night : round the lunar disk, a crown of pale light has been perceived, which is thought to be the solar atmosphere, for its NO. II. H