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INTRODUCTION.

As, introductory remarks, it may not be uninteresting or unprofitable, to present some of the claims of Astronomy, and glance at its history.

The fears which superstition has originated, and by which it has agitated our race, are greatly diminished by recent advances in this science. Either luminary may have its light obscured by Eclipses; the Comet's luminous train

may stretch itself one fourth across the horizon; the Aurora Borealis may crimson the sky or span the heavens with an arch, and no terrors be felt, where this science is understood.

The husbandman is benefitted, both in seed-time and in harvest, by the light this science has thrown around him. The mariner, by its moonlight, to discern his longitude, traverses fearlessly the bosoms of oceans, five thousand miles from those shores, of which he dared not before to lose the sight. The merchant now cominits to winds and waves his treasures, and expects them safely returned with large increase.

Geography has received a new continent from the confidence of Columbus, that the earth was spherical. History and chronology have had their facts confirmed, or their errors corrected, by astronomical calculations carried backward. It may be safely said, that all the arts and sciences, all the business and employments of man, have been highly benefitted by the advances made in this science.

But its intellectual and moral influence, renders it of inestimable value. With a field of immeasurable extent to be explored, with magnitudes, distances, and motions, vast and astonishing; the intellect becomes expanded, and the imagination enriched by every acquisition hore made. And the moral sensibility which can disceru.

and appreciate infinity of excellence, will find all its energies elevated and inflamed, by the ennobling and sublime discoveries it every where makes of the Creator's perfections.

HISTORY. Within a few centuries subsequent to the Deluge, Astronomical observations were made in China, in Hindostan, at Nineveh, at Babylon, and in Egypt.' But the Greeks first gave method, and body, and form to this science. It is even believed, that Pythagoras five hun dred years before the Christian era, discovered and taught the outlines of the true theory of the solar system. If so, 2000 years rolled away before it was again revived.

About 130 years after the birth of Christ, Ptolemy, an Egyptian Astronomer, published and defended the theory, which bears the name of Ptolemaic, but which was a mere accommodation of the science to the popular prejudices of the illiterate multitude. It supposed the Earth at rest in the centre of the Universe, with all the other material worlds revolving around it from east to west in 24 hours, while the Moon, the planets, and the Sun had other motions of less regularity, but all acknowledging Earth as their centre.

Other Egyptian Astronomers soon discovered, that the motions of Mercury and Venus, could not be reconciled with the Ptolemaic theory. They therefore concluded these two planets revolved around the Sun, as their centre. This theory is denominated the Egyptian.

About the commencement of the 16th century, Copernicus taught that the Sun is the centre of all the planetary motions.

Galileo, Kepler, Newton, and La Place, by their inventions and discoveries, have since established this theory on an immoveable basis. The ephemeral hypothesis of Tycho Brahe, appears to have been invented more to allay the fears of superstition, than to subserve the interests of science.

ELEMENTS OF ASTRONOMY.

CHAPTER I.

GENERAL VIEW.-THE SUN. ASTRONOMY is that sublime and useful SCIENCE, which treats of material worlds, and is divided into Descriptivé, Physical, and Practical, Astronomy.

Descriptive Astronomy teaches the magnitudes, densities, distances, and diversified motions of the Sun, the PLANETS, COMETS, and FIXED Stars, with their interesting vicissitudes of day and night, summer and winter); and other sublime PHENOMENA in their circumstances.

Physical Astronomy developes the laws of motion, or the uniformity, in which the irresistible energies of their Author govern the mighty movements of material worlds.

Practical Astronomy relates to Astronomical Instruments and Observations, and will be omitted in this elementary treatise.

Among the celestial bodies, the Sun and Moon are termed luminaries; the others are called stars. Stars are also distinguished into planets and fixed stars.

The PLANETS, though they appear like the fixed stars, are all opaque, or dark bodies, moving in a regular order round the Sun, from west to east, receiving light from that luminary, and shinin only by reflected light.

What is ASTRONOMY? How may it be divided ? What is descriptire astronomy? What is physical astronomy? What is practical astronomy ? What are called luminaries ? Are all apparent stars, fixed stars ? What are plancts ?

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