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geographers divide the surface of the earth, to be extended to the heavens; so that the whole circumference of the horizon of the heavens is supposed to be 300 degrees, or proportional parts; half is 180 degrees, and a quarter is 90 degrees. And as we see one-half of the heavens above the horizon, it is of course 180 degrees from one side of the horizon, in a line passing over our heads, to the side directly opposite; and of course from the point over our heads, called the zenith, it is 90 degrees to the horizon on every side.

Remember, then, that the whole heavens are 360 degrees, or proportional parts round, and that from the point directly over head, it is always 90 of these degrees down to the horizon.

An observer of the heavens will discover the progression of the whole, from east to west, by a quarter of an hour's attention. Let him bring a star, in any part be tween the zenith and the southern part of the horizon, into apparent contact with the end of a house, steeple or other fixed object, and he will in a few minutes per ceive the motion of that star, and of the whole heavens, from east to west.

It may be proper for the student now to consider, that this general motion of the whole heavens is merely appa rent and is occasioned by the rotation of the earth on Its axis in a contrary direction. Of course, if the spectator is moving on the earth from west to east, the dietant stars will appear to move from east to west.

The rising and setting of all the distant heavenly bo dies will, hence, be easily understood. The earth furm completely round every twenty-four hours: every inhabitant of it will, therefore, be carried round towards all the bodies out of it, and distant from it, every twenty four hours. Hence, the rising and setting of the Sun the succession of day and night and all the dependent phenomena.

This progression of the whole heavens from east to west the rising of some stars in the east, and the setting of others in the west & are objects which, viewed in this manner, will leave impressions much stronger than the mimic representation of the same phenomena on the ces

lestial globe. The immensity of the great vault of henven, the still, solemn, uniform motion; the accompanying association of the immeasurable distances, the apparent perpetuity, and the countless numbers of the stars, will fill the mind with reverence and devotion towards the omuipotent, influite, and eternal Author of the whole!

Having thus obtained ocular demonstration of the motion of the stars from east to west, or rather of the motion of the earth in the contrary direction, it will then be necessary to attend to another circumstance which is a consequence of that motion.

A slight consideration will evince, that the stars imme diately above the axis on which the earth may be sup posed to turn, will appear to remain stationary over those places, at both ends of the axis. In turning wheel on a fixed axis, all the parts of the circumference will successively present themselves to different objects but the axis will continue to point to the same place. If the wheel be supposed to be a globe revolving on a axis, the effect will be the same; the point of the axis, called the pole of the globe, will point to the same spot, while all the parts will perform smaller or larger cir cuits, in proportion as they are removed in a greater of less degree from the poles.

It is important, then, to be able to determine the points in the heavens which are opposite to the poles o. the earth; these always appear to stand still, while the alber stars appear to make a daily circuit round them. As, however, we can only see 90 degrees in the heavens from the point over our own heads, the inhabitants of no part of the earth can see both poles, except those who live at the equator, from which both poles are distant ninety degrees. The poles of the heavens may therefore be seen at the equator, exactly in the horizon, in the 1orth and the south; but if you travel or sail one degree to the north of the equator, so as to be within 89 degrees of the north pole, you will, of course, see one degree beyond the north pole, and not so far as the south pole by one degree; because, as before stated, you can always see 90 degrees in the heavens, from your zenith,

or place over head, In England, which Hes between 50 and 60 degrees from the equator, or within 40 or 50 des grees of the north pole, we always see 50 or 60 degrees beyond or below the north pole; or, in other words, the north pole in the heavens, or the stars immediately over the north pole of the earth, will be 50 or 60 de: grees high.

Rather above mid-way between the horizon and the zenith, in this northern part of the heavens, we who are in England must look for the north pole of the heavens, or the part which never appears to move, It happens that there is a star so near the north pole, that for all ordinary purposes it may be taken for the north pole itself; and this star may always be found very easily, by means of two other stars which point to it in a right line, During the winter months, these stars, which are in the constellation of the Great Bear, are to be found with the other stars of that remarkable constellation, on the eastern side of the pole. They are about six degrees asunder, and the nearest is five times that space, or thirty degrees from the polar star, at which they seem to point, and are, thence, called the Pointers.

The north pole star being thus found, it will be a pleasing employment to observe, that all the stars appear to move round it, according to their several distances, while it constantly stands still. An hour's contemplation of this star, and of the motions of the rest of the heavens, while it remains an immoveable centre, will teach more to the uniformed in astronomy, than a thousand lessons or lectures in the closet,

On a winter's evening, the other remarkable objects in view, will be the Pleiades, or seven stars, in the southeast; and below them, a little to the east, the grand constellation of Orion and still lower, the dog-star Sirius, the brightest of all the fixed stars. The three bright stars together in a line, called the Belt of Orion, are at about equal distances from the Plejades and Myrius; that is, about twenty flos degrees from each. Besides remembering this distance, and that of the Pataters, before-mentioned, for the sake of occasional comparisons, it will be useful to recollect, that the most northern of the three

stars in the Belt of Orion, is exactly over the equator so that from that star to the north pole atar is exactly ninety degrees.

The Pliades are in the Zodiac, on the south side ; and so is the red star Aldeberan, near them; and the two bright stars about forty degrees to the left, called Castor And Poliuæ, or the Twins, are also in the Zodiac, and about five degrees north of the Sun's place, on the 12th of July.

On such an evening, the Milky-Way will be seen in the west, as a light cloud; supposed by some to be formed of a mass or shoal of stars, almost infinite în number, but indistinct from their distance; though others suppose it to consist of a luminous space, and not of

stars.

A celestial globe, rectified to the day and hour, will point to other objects; an ephemeris will indicate the names or places of the planets which may then be above the horizon; and any telescope will render visible many other interesting and wonderful phenomena.

Should the Moon be visible, the motion in her orbit may be nightly traced by her approximating to, or receding from, certain stars and the same may be ob served in the motion of the planets in their orbits.

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The morning and evening stars are the bright planets, Venus and Jupiter, so called from their rising or setting with the Sun. Mars is red; Saturn of a leaden colour; Herschel is so distant, and Mercury is so near the Sun, that they can seldom be seen but with a telescope.

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Very small telescopes will shew most of the celestial phenomena Jupiter's moons, Saturn's ring, the moonlike phases of Venus, the Pleiades, the luminous space in the sword of Orion, the Spots in the Sun, and the mountains in the Moon, may all be seen with such telescopes as are bought for ten or 'fifteen shillings. Galileo made all his great discoveries with a telescope eight or ten inches long, and which magnified only ten or twelve times.

JUPITER, HIS MOONS AND BELTS,

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