grovelling conceptions and prejudices of the ignorant, and our understandings clearly convinced of the immutability and omnipotence of the Supreme Being. And besides enlarging the sphere of human knowledge, and contributing to the wants and conveniences of man, astronomy has also been greatly useful in dissipating the alarm and dread occasioned by extraordinary appearances in the heavens. The portentous advents of comets, formerly considered the sure forerunners of some direful catastrophe, either in the moral or physical world, are now witnessed without consternation or fear, all the phenomena attending them being rationally explained and accounted for. Total eclipses also, which were in ancient times deemed ominous of dreadful evils, now cease to excite alarm or terror, as they are known to be produced by natural causes, and to be regular in their returns as the seasons of the year, or the morning and evening. Indeed, the benefits this sublime science has conferred on society are so great and numerous, that it justly claims a right to our esteem and respect; and there is not, without doubt, another science more deserving our attention, or worthy to occupy and amuse our leisure moments. The study and investigation of the objects of the visible heavens is a delightful and innocent amusement for the evening, or the most lonely and silent hours of night. But what is far more, by observation and meditation on the celestial canopy, we are irresistibly led, from the beauty and grandeur of the scenery, to the contemplation of the immensity and infinite goodness of the great Author,

By astronomy we learn that the sun is more than a million times larger than our earth, and at such a distance, that, seen from the sun, our earth would appear no larger than a star appears to us. We also learn, that the stars are at such an immense distance from us, that a cannon ball, flying at the same rate as when first discharged, would not pass from the earth to the nearest fixed star in less than seven hundred thousand years; and that being visible from this vast distance, they cannot be less luminous, or less in size, than our sun: each is therefore, probably, a sun to another system, and has a retinue of worlds revolving round it, and enlightened and warmed by its influence: so that instead of one world, and one sun, in the universe, as many imagine, "astronomy discovers to us such an inconceivable number of suns, systems, and worlds, dispersed through boundless space, that if our sun, with all the planets, moons, and comets, belonging to it, were annihilated, they would be no more missed by an eye that could take in the whole creation, than a grain of sand from the sea-shore-the space they possess being comparatively so small, that it would scarcely be a sensible blank in the universe."

The magnificence and grandeur which we every where behold in the universe, is worthy the Great Being who created and sustains it; yet all this magnificence is one day to pass away; and hence, by His example, He would point out the vanity of all sublunary things, and call our attention to higher destinies and regions. It is not, then, the immensity or multiplicity of these vast orbs that should challenge our attention; they may excite our astonishment, and produce an awful respect for their Creator; but they are nothing more than inanimate heaps of matter, incapable of knowing that Being that called them into existence, and destined one day to perish. Of all created beings, we find only man possessed of that immortal principle destined to survive the wreck of matter, and capable of knowing, serving, and enjoying that Great Being that called it into existence. One immortal soul, therefore, is of more value in the sight of its Creator, than all those vast orbs that roll their immense masses through the expanse of heaven; and hence, we need not wonder that He has done so much for its preservation.

NAMES.ND CHARACTERS OF THE SIGNS, PLANETS, AND ASPECTS. Aries, ; Taurus, 8; Gemini, II; Cancer, ; Leo, ; Virgo, m; Libra, Scorpio, m; Sagittarius, 1; Capricorn, V; Aquarius, ; Pisces, ; or O; Moon, OD; Mercury, ; Venus, Q; Earth, ; Mars, Vesta, Juno, ; Ceres, ?; Pallas,; Jupiter, 2; Saturn, h; Herschel, Conjunction, 6; Sextile, *; Quartile, ; Trine, A; Opposition, 8; Ascending Node, 8; Descending Node, .

Sun,

CHAPTER I.-THE EARTH.

[When any astronomical word or term occurs that is not understood, the Reader may turn to the GLOSSARY, and find it explained.]

The term astronomy is compounded of two Greek words, which signify the law, or the knowledge of the stars.

It is a mixed branch of the science of mathematics: it treats of the heavenly bodies. The heavenly bodies are the Sun; the Primary Planets; the Secondary Planets, which are called Moons and sometimes Satellites; the Comets; and the Fixed Stars. All these bodies are worlds, supposed to be inhabited. Many of them are larger, and some of them are smaller, than our earth.

The earth is the first object to be considered in astronomy.

The earth, or this world which we inhabit, is one of the primary planets: it is a globe, sphere, or ball, a round body, about 8000 miles in diameter, and 25,000 in circumference. This has been proved by incontestable evidence, and will appear plain and rational to any one who obtains but a slight knowledge of astronomy. The earth has been travelled or sailed round many times. The masts of a ship, at a distance at sea, are seen, while the hull is hid by the convexity of the water.

The earth being so large a body, the irregularities of its surface, the hills and valleys, take off no more, and in fact not a tenth part as much in comparison, from its circular figure, as the little dents and bunches do from the roundness of an orange; or as grains of sand do from the roundness of an artificial four inch globe.

All animals, bodies, or things, on whatever side of the earth, are kept on its surface by attraction or gravitation: the earth attracts, or draws to its surface, or towards its centre, all substances, or objects, or things, that are on or about it.

The terms up, and down, refer only to the centre of the earth: up means from the centre, and down. means towards the centre of the earth.

To the people who are on the opposite side of the earth, up, as regards space, or the heavens, is in a direction exactly contrary from what it is to us; for a right line which is down to us, if continued through, and beyond the opposite side of the earth, would be up to the inhabitants of the opposite side. The earth turns round on its axis from west to east once in 24 hours, and thus by turning one part of its surface to the sun, and another part of its surface from the sun, makes day and night.

This motion of the earth round its axis from west to east, makes the heavenly bodies, the sun, moon, stars, &c. appear to move round the earth from east to west once in 24 hours.

In 12 hours from now, (if we are near the equator,) to us as regards space, or the heavens, up will be in the same direction that down now is, because the earth will then have turned half round, and our heads will point in the same direction that our feet now do.

We now think that we are on the top part, or upper side of the earth, (in reality, the earth has no top or bottom part, or one part is as much the upper side as any other,) and in 12 hours, we shall also think that we are then on the upper side of the earth, when our situation will be what the under, or bottom part, or side of the earth opposite to us, now is; because the earth will have turned half round, and that part of the heavens, or that part of space, and those stars that are now directly under our feet on the opposite side of the earth, (if we are at, or near the equator,) will then be directly over our heads. Up and down, therefore, are only relative terms; they relate exclusively to the centre of the earth.

In whatever part, or on whatever side of the earth we are, we have the sky over our heads, and our feet towards the centre of the earth: we call it up, over our heads, and down under our feet: that is, towards the centre of the earth is down, and proceeding from the centre, is up.

The apparent circles of motion of the heavenly bodies, caused by the motion of the earth round its axis, are very different, in different places. The celestial sphere is called right, parallel, or oblique, as the plane of the equator is perpendicular or at right angles to the plane of the horizon, or, as it is parallel or oblique thereto.

The inhabitants of the earth at the equator, are in a Right Sphere, because here the plane of the equator is perpendicular, or at right angles to the plane of the horizon; the poles being in the horizon, and the plane of the equator passing through the zenith and nadir, all the apparent circles of motion of the heavenly bodies are perpendicular or at right angles to the horizon; that is, all these bodies rise from the horizon, and descend to it, at right angles, and are just as long above, as they are below it; and the days and nights are always equal.

The poles are in a Parallel Sphere, because here, the plane of the equator is parallel to the plane of the horizon; the poles are in the zenith and nadir; all the apparent circles of motion of the heavenly bodies are parallel to the horizon, that is, they all revolve round without setting or without rising: those stars above the horizon never set, and

A

those below it never rise: the sun revolves parallel to the horizon without setting for six months; and then revolves in the same manner as long below it, without rising, making but one day and one night, of six months each, in the year. At the summer solstice the sun is highest above the horizon, his altitude being always equal to his declination. At the equinoxes the sun is in the horizon for more than 30 hours, revolving with his lower limb below, and his upper limb above the horizon.

All places between the poles and the equator are in an Oblique Sphere, because the plane of the equator is oblique to the plane of the horizon; the pole is between the zenith and the horizon; the apparent circles of motion of the heavenly bodies are oblique to the horizon, that is, these bodies rise and go down obliquely to the horizon; all at a distance from the equator, are not the same time above, that they are below the horizon; and the days and nights are never equal except when the sun is in the equator.

Note-The elevation of the pole above the horizon at any place is always as many degrees as the place is from the equator; that is, the altitude of the pole is always equal to the latitule of the place.

The earth is 95 millions of iniles from the sun, and besides revolving round its own axis once a day, the earth moves round the sun once a year, similar to a top that leans a little sideways and spins round itself, or its axis, and at the same time moves in a circle round a nail or pin on the floor.

This leaning of the earth's axis, 23° 23' from an erect position, causes the different seasons and the different length of the days and nights. If the earth's axis were perpendicular to the plane of the ecliptic, that is, if the earth moved round the sun with its axis upright, similar to a top that stands erect and spins round itself or its axis, and at the same time moves round a nail or pin on the floor, there would be no difference of seasons, and the days and nights would always be equal, 12 hours.cach.

This may be made plain by taking a small artificial globe, or any ball, with a wire through it, to represent the axis and poles of the earth, and carrying the ball which represents the earth round a light which represents the sun; thus, if you have no globe or other ball, take a common ball of yarn 2 or 3 inches in diameter, or larger, or smaller than this; take a straight wire, as long, or longer than the diameter of the ball: pass the wire through the ball, so that the centre of the wire shall be in the centre of the ball; tie a string round the ball so that every part of the string shall be equally distant from the ends of the wire. Now call the ball the earth; the wire its axis and poles; and the string the equator call the flame of a candle on a table the sun: place the south pole of the earth on or over the table 2 or 3 feet south of the sun, (the centre of the earth being just as much above the table as the centre of the sun is,) let the axis or the north pole lean a little, (that is, 23° 28') from a perpendicular line towards the north. The earth will now be shown at the Summer Solstice, that is, at June 21st; keeping the axis in this position, turn the earth round its axis, turning the part next the sun from east to west; that is, turn the earth contrary to the way the hands of a watch move; to all the places the sun shines on, it is day; and to all the places the sun does not shine on, it is night; as the places come into the light of the sun, the sun rises to those places, and as they go out of the light of the sun into the dark, the sun sets to them. As the earth turns on its axis, it .will be seen that all places north of the equator are longer in the light than they are in the dark; therefore the days at those places are longer than the nights; and at the pole there will be no night, as the sun shines on the earth beyond the pole and places near the pole, as the earth turns on its axis, will not go into the dark at all, but have constant day; and places near the south pole will have constant night. Now remove the earth, and place it 2 or 3 feet east of the sun, keeping the axis leaning in the same manner to the north, and the earth will be shown at the Autumnal Equinox, Sept. 23d. Again, place the earth 2 or 3 feet north of the sun, and it will be represented at the Winter Solstice, Dec. 21st.; and if it be placed west of the sun, it will be shown at the Vernal Equinox, March 21st.

The earth's axis always keeps its parallelism; that is, the axis in any one part of its orbit, is always parallel to what it was in any other part; or the axis always leans towards the same part of space, or the heavens; or the variation is so little that it cannot be perceived in many years.

3 On one side of the sun, the north pole leans towards the sun; and when the earth has moved half round the sun, or half through its orbit to the other side of the sun, the north pole leans from the sun. When the earth is on one side of the sun, and the north pole leans towards the sun and the south pole leans from the sun, the north pole is enlightened by the sun and the south pole is in the dark; and when the earth is on the other side of the sun, and the south pole leans towards the sun and the north pole leans from it, the south pole is enlightened by the sun and the north pole is in the dark.

When the earth has moved from either of these sides or points of its orbit one quarter round the sun, or through one quarter of its orbit, neither pole leans towards or from the sun, but the axis and poles lean sideways to the sun, and both poles are enlightened. While the earth is moving through one half of its orbit, the north pole is constantly enhtened by the sun, and the south pole is in the dark; and in all places in north latitude, or north of the equator, the days are longer than the nights; and in all places

south of the equator, or in south latitude, the days are shorter than the nights: and while the earth is moving through the other half of its orbit, the south pole is constantly enlightened by the sun, and the north pole is in the dark; and in all places south of the equator the days are longer than the nights; and in all places north of the equator, the days are shorter than the nights.

When the earth is at either equinox, both poles are just in the edge of the light, and the days and nights are equal all over the world.

As regards a spectator at the sun, the earth moves round the sun from the right hand to the left. It is generally said the earth moves from west to east; but it is evident that if in one part of its orbit, it moves from west to east, in the opposite part it moves from east to west, as regards space, or the heavens. And as regards a spectator at the sun, as the earth moves round its axis, the side of the earth next the sun moves from the left hand towards the right, and consequently the side opposite the sun moves from the right hand to the left: that is, the diurnal motion of the side of the earth next the sun, is in an opposite direction to the annual motion of the earth in its orbit round the sun; and the diurnal motion of the side of the earth opposite the sun is in the same direction as the motion of the earth in its orbit.

The annual motion of the earth round the sun, makes the sun appear to move round the earth once a year. And the diurnal motion of the earth round its axis, makes the Sun and other heavenly bodies appear to move round the earth once a day.

We say the diurnal motion of the earth is from west to east, because the apparent motion of the sun and moon from rising till setting is from east to west; but it is evident that when one side of any globe or ball that turns round its axis, is moving from west to east, the opposite side, in turning round the axis, is moving from east to west: but we are as insensible of this with regard to our own motion as we are that the direction of our feet at six o'clock in the morning is opposite to their direction at six o'clock in the evening. So if we should set out from any place, and travel directly forward without turning either to the right or to the left, we should in time travel entirely round the earth, and arrive at the place we started from; and this would be the case, in whatever direction we started. When at half the distance round the earth, up, to us, would be exactly the opposite direction it was when we started; and we should be travelling towards the opposite part of the heavens to that we were when we started; but we should not be sensible of this, but should think we were always travelling towards the same part of the heavens, and that up was always in the same direction.

East and west are only relative, or local terms; at the poles, there is no such thing as east or west, but every direction from the north pole, is south; and every direction from the south pole, is north. When it is said that the earth moves in its orbit from west to east, the meaning is, that it moves from right hand to left as seen from the sun. And when it is said that the earth revolves round its axis from west to east, the meaning is, that as seen from the sun, the side of the earth next the sun, moves from left hand to right, and the side opposite the sun moves from right hand to left; but the motions of the earth have already been explained with a ball representing the earth, and a light representing the sun; by carrying the ball round the light from south to east and north, &c.

Though the earth is a globe, yet seen from the sun or moon, or from a distant point between us and the sun or moon, it appears like a flat round surface, as the sun or moon appears to us. This appearance is called the earth's disk.

By the motion of the earth round its axis, places on its surface describe, in 24 hours, circles or paths parallel to the equator. These circles or paths, are the parallels of Jatitude of those places. As seen from the sun, these paths or parallels on the earth's disk, appear different; they vary with the sun's declination. When the sun is in the plane of the equator, all the parallels of latitude on the earth appear to a spectator at the sun to be straight lines across the carth's disk, because the earth appears so small that the spectator may be considered in the plane of each parallel. But when the sun is not in the plane of the equator, that is, when he has north or south declination, the spectator at the sun being not in the planes of the parallels, they appear to him to be curve lines or ellipses on the earth's disk. As seen from the sun from sunrise till sunset, or from 6 in the morning till 6 afternoon, places on the earth describe paths from west to east across its disk. These paths are the parts of the parallels of latitude of the places which are described in the daytime.

The sun appears to rise from behind the eastern part of the earth, and to set behind the western; because we look towards the east to see the sun rise, and towards the west, to see it set: but it is only from behind the eastern part of that very small portion of the earth which we can see, that the sun rises from behind; and it sets behind the western part of the same small portion. The diameter of the earth's disk is nearly 8000 miles, that is, it is nearly 8000 miles from the eastern to the western part of the earth. The earth being round, we can see only that part of it which is within a few miles of us. At sunset, near the equator the whole portion of the earth which we can see, together with what the sun sets behind, is nearly 8000 miles east of the western part of the earth: for by the motion of the earth on its axis from sunrise till

sunset, we have been carried nearly 8000 miles from west to east. The sun, therefore, in reality, rises from behind the western part of the earth, and sets behind the eastern; for we can see that part of the earth which the sun sets behind, and we can see only the part where we are, or within a few miles of us.

The sun, the source of light and heat to the earth, and other planets, and their centre of motion, and centre of gravity, is an immense globe, more than a million of times larger than this world. The moon is of itself, a dark body, and shines only by reflecting the light of the sun. It is a globe 2180 miles in diameter, being about 49 times smaller than the earth, and 240,000 miles distant from the earth.

The moon is a satellite to the earth, its centre of motion, and centre of gravity. The moon moves round the earth from the sun to the sun again once in about 29 days; and is carried with the earth round the sun once a year. The motion of the moon round the earth once in 29 days, is in the same direction, and nearly in the same plane, in which the sun appears to move round the earth once a year.

The bright part of the moon, that is, the part visible, is what the sun shines on. At Full moon, the sun being on one side of the earth, and the moon nearly on the other, we see nearly all that part which the sun shines on, the enlightened part being towards us.

At new moon, the moon being nearly between the earth and the sun, the enlightened part is wholly turned from us, we can see no part that the sun shines on, and of course we can see no part of the moon, it is entirely invisible.

At the Quarters, or Quadratures, we can see only half of what the sun shines on. Note.-When the moon, or any other planet, is said to be in the ecliptic or in the equator, &c. the meaning is, that it is in the plane of the ecliptic, or in the plane of the equator, &c.

The moon is eclipsed when the sun does not shine on it. An eclipse of the moon, which can only happen at the full moon, when the sun is on one side of the earth, and the moon on the opposite side, is caused by the moon's being in the earth's shadow; that is, the earth being directly between the sun and moon, prevents the sun from shining on the moon.

An eclipse of the sun, which can happen only at the time of new moon, is caused by the moon's coming between the earth and the sun, and hiding the whole, or a part of the sun, from those parts of the earth to which the sun is eclipsed: that is, the moon's shadow falls upon those parts of the earth to which the sun is eclipsed.

If the moon's orbit coincided exactly with the plane of the ecliptic, that is, if the moon moved in this plane, she would be eclipsed at every full, and the sun would be eclipsed at every new moon. But the plane of the moon's orbit makes an angle with the plane of the ecliptic of about 50; one half of the moon's orbit being elevated about 50 above the plane of the ecliptic, and the other half depressed as much below it. The plane of the ecliptic, therefore, cuts or intersects the moon's orbit in two points diametrically opposite to each other: these points are called the moon's nodes. The moon is never in the ecliptic, or in a right line with the earth and sun, except when she is in one of her nodes; consequently she can never be eclipsed, or eclipse the sun, but when she is in or near one of her nodes. That node from which the moon ascends northward, or above the plane of the ecliptic in north latitude, is called the Ascending Node; and the other the Descending Node, because the moon, when she passes it, descends below the ecliptic to the south.

These things may be made plain, by taking a small ball, as a small marble or bullet about half an inch in diameter, for the earth; a smaller ball, as a pea or a buck shot, for the moon, and the flame of a candle for the sun.

As the sun is so much larger than the earth, to give these their proper proportions as to size and distance, if the flame representing the sun, is 2 inches long, or 2 inches in diameter, the ball to represent the earth should not be the lundredth part of an inch in diameter, or it would not be as large as a mustard seed; and the ball to represent the moon would be 49 times less. The distance of the earth from the sun would be about 17 feet, and the distance of the moon from the earth would be about half an inch. But we cannot well preserve the just proportion in representing the sun, moon, and earth, by machinery.

Place the earth 2 or 3 feet north of the sun, on a level with the sun; place the moon 4 or 5 inches east of the earth, on a level with the earth and sun; carry the moon round the earth, keeping it at about the same distance from the earth, carrying it from east to north, then to west, and then to south, &c. but not keeping it on a level, or in the same plane with the earth and sun; when the moon is north of the earth, and in this case in opposition to the sun, let it be above the level, or plane, in which the earth and sun are, and 3 or 4 times its diameter above the earth's shadow: when it is south of the earth, and in this case in conjunction with the sun, and nearly between the earth and sun, let it be below the level or plane in which the earth and sun are, so that its shadow may fall 3 or 4 times its diameter below the earth. This is the manner in which the moon moves round the earth, and in this case it is plain, there could be no eclipse either at the new or full moon. When the moon is on a level with the sun and earth, that is, when it is in the same plane, or in the plane of the ecliptic, it is in one of its nodes. In this case, it was in its ascending node when it was east of the earth; and in its descending node when it was west of the earth; it was in the highest part of its orbit when it was north, and in the lowest part, when it was south of the earth. The nodes, or places in its orbit, where the moon is, when it is on a level with the earth and sun, are continually moving at the rate of about 19o in a year contrary to the way the moon moves in her orbit.