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Mars in conjunction with Jupiter at 10 in the morning of the 26th, difference in declination 51'.

The Asteroids.

Hrs. Min.

Vesta, 4th day. Right Ascension 8 44. N. Declin. 23° 56′

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Eclipses of the Satellites of Jupiter.

None of these will be visible this month.

Saturn stationary near 1 in Leo on the 10th. In quadrature at 30 min. after 2 of the morning of the 30th.

FORM OF SATURN'S RING.

May 21st.-Semi-transverse axis

Semi-conjugate axis

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Uranus in quadrature at 30 min. after 2 of the morning of the 9th. Stationary on the 22nd.

In ardent contemplation's rapid car,
From earth, as from my barrier, I set out.
How swift I mount; diminished earth recedes :
I pass the moon; and from her farther side,

Pierce heaven's blue curtain; strike into remote ;
Where, with his lifted tube, the subtle sage

His artificial airy journey takes,

And to celestial lengthens human sight.

I pause at every planet on my road

And ask for Him who gives their orbs to roll,
The foreheads fair to shine From Saturn's ring,
In which of Earths an army might be lost,
With the bold comet take my bolder flight,
Amid those sovereign glories of the skies,
Of independent native lustre proud ;

The souls of systems; and the lords of life,
Through their wide empires!—

What behold I now!

A wilderness of wonder burning round,

Where larger suns inhabit higher spheres.

Sphere of the Fixed Stars.

Positions of the principal stars on the 1st of the month, at 10 in the evening.

Castor and Pollux near the western horizon. Ursa Major in the zenith. A line drawn from the polar star by λ and u, in Ursa Major, points out Regulus, or the Lion's heart; another line, from the same point, through

γ

in Ursa Major, passes through Denebola, or the tail of the Lion. Another imaginary line, through 8 and Y in the Great Bear, passes through Leo Minor, Regulus, and Cor Hydræ. West of Cor Hydræ is Procyon, east is Crater and Corvus, -the latter formed of an imperfect square of four stars. Spica Virginis, Arcturus in Boötes, and Denebola, form an equilateral triangle,Arcturus the most elevated, and Denebola to the west. A line through ɛ and ŋ, in Ursa Major, passes through Gemma in Corona Borealis ; another line from Arcturus,

through Corona Borealis, passes through Hercules to the bright star Vega in Lyra. Vega, Althair in Aquila, and Delphinus, form an isosceles triangle, of which Vega is the summit.

TELESCOPIC OBJECTS.

Leo. Variable stars, E, 4, 25, and i. Double stars, w, both of which are red. 54, the largest white, the smallest greyish white. 7, the large star red, the small star bluish. p, the large white, the small a pale red. is a beautiful double star. 7, 83, and 88, are also double stars. 90 is a triple star. Regulus is a double

star.

y, in Leo, is a binary system, the large star white, the small reddish white From the interval between the two stars, the ratio of their diameters, and the variation in the angle of position, it has been found that the apparent orbit of the small star is elliptical, and that it performs a whole revolution in about 1200 years in a retrograde direction. Between and are two faint nebulæ; two other nebulæ, of the same description, between p and ↓, -these nebulæ, though faint, are, in general, resolvable into stars.

Virgo. In this zodiacal constellation 20 and 91 are variable stars. E, 9, 7, are double stars. y, in Virgo, is a binary system, both the stars of which it is composed are white, and nearly equal in magnitude; a revolution is performed about their common centre of gravity in 708 years. In and near the bosom and right wing of Virgo are no fewer than eighteen nebulæ, some of which are bright in the centre, but, in general, they are of a faint description.

On Nature's alps I stand,

And see a thousand firmaments beneath!
A thousand systems! as a thousand grains!
How can man's curious spirit not inquire
What are the natives of this world sublime,
Of this so foreign, unterrestrial sphere,
Where mortal, untranslated, never strayed?
Ye borderers on the coasts of bliss! what are you?
A colony from Heaven? or only raised,

By frequent visits from Heaven's neighbouring realms,
To secondary gods, and half divine?—

COMETARY ASTRONOMY.

Tails of Comets. The tail of a comet is a continuation of the envelope, which, after nearly encompassing the hemisphere of the nucleus that is next to the sun, diverges to a greater or less extent in the opposite direction. There are some comets which have no tails, and these, it may be observed, are those whose periods of revolution are short, and in their physical constitution, mere collections of nebulous matter.

Comets have no tails till they approach the sun at the first the tail is scarcely perceptible; as the comet advances, the tail increases in length, till having wound its way round the solar orb, it diminishes in length as its distance from the sun increases, and, ultimately, disappears. The tail is always turned from the sun, whether the comet be approaching or retreating, and there can be no doubt but that this direction of it is produced by the solar action. According to some philosophers, the rays of light push off the matter of the nebulous envelope, after it has been raised by an approximation to the sun; according to others, the tail is

produced by an unknown power of repulsion in the sun; others again argue, that the tail is raised by the attraction of the sun, in the same way that the tides of the ocean are raised by the moon; another opinion is, that there is a very dense atmosphere about the sun, in which the very rare matter of a comet's tail ascends as smoke does in the terrestrial atmosphere; others again attempt to explain the phenomenon on electrical principles, and assert, that just as bodies charged with one kind of electricity repel each other, so the tails of comets have a natural tendency to avoid or fly from the sun.

Without entering on the vain fancies, and unphilosophical reasonings connected with this branch of our subject, we conceive that the first mentioned hypothesis is an approximation to the truth, namely, that the solar rays impel or push off the nebulous matter raised about the nucleus into the form of a streaming tail; this nebulous matter may be supposed to be generated by the unequal action of the sun on the comet,-an unequal action, caused by its varying its distance so much from the centre of its motion; when near its aphelion it would have its physical constitution considerably changed,― vapours and exhalations would be generated and accumulated in great quantities: loaded with these vapours, it would return towards the sun, the influences of which would elevate them to a considerable height above the nucleus; as it approached nearer, and felt more powerfully the solar energy, these accumulated vapours would be impelled in the direction in which light, heat, and other emanations, proceed from the sun, --that is, in right lines; so that if a comet were urging its course direct to the centre, the tail would be in

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