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or the stars immediately over the north pole of the earth, will be 50 or 60 degrees high.

Rather above mid-way between the horizon and the zenith, in this northern part of the heavens, we are in England, to 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 uninformed 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 distance from the Pleiades and Sirius; that is, about twenty-five degrees from each. Besides remembering this distance, and that of the Pointers, 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 star is exactly ninety degrees.

The Pleiades 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 Pollux, 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 cluster of stars, almost infinite in 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 observed in the motion of the planets in their orbits.

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 pale colour; Herschel is so distant, and Mercury is so near the Sun, that they can seldom be seen but with a telescope.

VENUS, AS SEEN THROUGH 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 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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252. The stars, according to their distances, are of seven sizes, called first magnitude, second magnitude, &c. down to the seventh magnitude, which can only be seen with a telescope. The stars may be distinguished from the planets by their twinkling; whereas the planets have a steady light.

Obs.-Having now acquired some knowledge of the wonderful things out of the EARTH, we will return again to it, observing, that these fixed stars and other celestial objects are constantly made use of to determine the relative situation of places; and that they are unerring guides both in regard to time and space.

253. Besides their motion round the Sun in their respective years, the earth and the planets also turn round on their own axes, and by turning to and from the Sun, produce to their inhabitants, alternate light and darkness, or day and night; so that their seasons and years are produced by the grand revolution round, the Sun; and their days and nights by turning on their

own axes.

Obs. If a boy throw a ball out of his hand, besides going forwards, it turns round on its axis, and this is the precise motion of the earth and planets.

254. The distances of the seven primary planets from the Sun, in round millions, are-Mercury 36, Venus 68, Earth 93, Mars & 142, Jupiter 2 486, Saturn 892, and Herschel 1800 millions of miles from the Sun. Their diameters are respectively 3, 8, 8, 4, 89, 79, and 35 thousand miles.

And their periods of revolution are 3, 7, 12, 22, 144, 340, and 1000 months.

255. In their grand orbits, the planets do not move exactly in the same level or plane; but

each moves regularly in its own level. Nor are their axes exactly perpendicular to the plane of their orbits, but variously inclined; and this inclination produce the difference of their seasons, and, the different lengths of day and night.

256. The whole earth is calculated to be 4 times heavier than water? the Sun, Jupiter, and Herschel about the weight of water; Mercury nine times, and Venus six times heavier. In this way, taking matter for matter, it is found, that it would take a million of our earths, to make a body equal to the Sun.

257. Next to the Sun, the Moon is that of the heavenly bodies, which the most interests our curiosity. She is but 240,000 miles distant from the earth, only 2346 miles in diameter, and near 7000 miles in circumference. She accompanies the Earth in its annual orbit; and, during that period, goes herself nearly thirteen times round the earth in an orbit of her own.

258. The moon goes round her orbit in 27 days 8 hours; but, as the Earth moves forward during the time, it is 29 days 12 hours before she returns again to a conjunction with the Sun. The Earth is sixty times larger than the Moon; or it would require sixty moons to make up the bulk of the Earth.

259. The mountains in the Moon are, however, higher than those on the Earth. For example, Mount Leibnitz, in the Moon, is five miles high, which is a mile higher than Chimboraço, in Peru. The surface of the Moon is, besides, covered with deep pits or vallies, some of them four miles deep.

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