No. VII. REFLECTIONS ON THE SOLAR SYSTEM. Quid potest esse tam apertum, tamque perspicuum, eum coelum suspeximus, coœlestiaque contemplati sumus, quam esse aliquod Numen præstantissimæ mentis, quo hæc regantur? CICERO, The heavens declare the glory of God, and the firma ment showeth forth his handy work.' DAVID. WHEN Winter extends his desolate domain, and we are deprived of all the beauties of contemplation in the vegetable world, the radiant orbs on high still shine with undiminished splendour, and inspire the religious philosopher with the most awful sentiments of wonder and devotion. Their prodigious magnitude and distances, with the regularity and harmony of their motions, all concur to declare, with the eloquent heathen philosopher and the royal Psalmist above, that, the hand that formed them is divine.' It is no wonder, then, that astronomy is a science of the earliest antiquity, and that it has claimed the admiration of all ages. Poets, philosophers, and historians, have all bestowed upon it the highest encomiums; and even kings' have enriched it with their labours. The poets, in particular, have been lavish in their praises of this Belus, King of Assyria; Atlas, King of Mauritania; and Uratus, King of the country situated on the shore of the Atlantic ocean; are severally recorded, as the persons to whom the world owes this noble science; and among the moderns, Alphonsus, King of Castile, enriched it with those tables that still bear his name. subject'. Of these, however, I shall be content to select a few only from the magnificent effusions of Young, whose sublime muse was more particularly devoted to nocturnal contemplations. How is Night's sable mantle laboured o'er, What wisdom shines! what love! This midnight pomp, The soul of man, His face designed to see, This prospect vast, what is it? - Weighed aright, "Tis nature's system of divinity, And every student of the night inspires, "Tis elder scripture writ by God's own hand. What read we here? -The existence of a God?- Why from yon arch, that infinite of space, Night opes the noblest scenes, and sheds an awe, Manilius, a Roman poet, wrote a poem on Astronomy, of which five books are extant. By what divine enchantment was it raised, Bright legions swarm unseen, and sing, unheard What magnificent ideas of the Creator and his works, indeed, does the starry firmament present! How far superior the subject to the most sublime conceptions of the human mind! Astronomy, indeed, derives from its nature a certain degree of dignity, and upon it, we should recollect that navigation (so important to the interests of this country), geography, and chronology, chiefly depend. By the aid of astronomy, man is enabled to pass the apparently boundless ocean, to penetrate into foreign climates, to become better acquainted with those which he inhabits, and regulate the dates of ages past. The heavens appear to us to be thickly spangled with stars of different magnitudes and degrees of brilliancy: these are called fixed stars and planets. The ancients, who knew so little of the motions of the planets, had no means of investigating the true disposition of their orbits, which is the cause of the variety of opinions formerly held on this subject. Some of their philosophers supposed the earth to be immoveable, as the centre of the universe, and that all the celestial bodies moved round her. Among these was Claudius Ptolemy, the ce lebrated astronomer and mathematician of Pelusium, in Egypt, who lived in the beginning of the second century of the Christian æra. Ptolemy, whose name is attached to this system, endeavours to prove that the earth, T, in the annexed figure, is immoveable in the centre of the uni verse, and he placed the Sun and the other planets in orbits that surrounded the orbit of the Earth in the following order, beginning with those which he thought were next the Earth; the Moon ); Mercury; Venus ; the Sun; Mars 8; Jupiter 24; and Saturn : after which, as the Georgium Sidus, or Herschel planet, was not then known, he comes to the fixed stars. When astronomers observed that the planets Mercury and Venus were sometimes nearer and sometimes farther from the Sun, and that Venus never departs from the Sun more than about 47 degrees, and Mercury about 28 degrees and a half; they soon discovered that the orbits of these planets could not be beyond the orbit of the Earth; because, if that had been the case, they would sometimes have appeared opposite to the Sun, that is, the Earth would sometimes have been between the planets and the Sun, which it never is. Hence the Egyptians thought that these two planets were satellites to the Sun, and turned about him, their orbits being carried with him in his revolution about the Earth. And they supposed the Earth immoveable, as the centre of the system, and that the other celestial bodies revolved about her once in twenty-four hours. Copernicus, with a view of obviating the inconveniences of the imaginary systems that had preceded him, began by assuming the diurnal motion of the Earth, or her motion round her own axis: this being admitted, he showed the necessity of her annual motion round the Sun in the ecliptic in something more than 365 days. With these two motions, he explained, with the utmost facility, the phenomena of the stations and motions of the planets. According to this theory, the Sun' S, is the centre of the planetary system, and the several planets, of which the Earth is one, revolve about him in the following order: Mercury; Venus ♀ ; the Earth 8; Mars &; Jupiter 24; and Saturn. Such was the true theory, and the full extent of it, as was then known; since which, another planet, the Georgium Sidus, has been discovered beyond the bounds of Saturn: and four other small planetary bodies are now known to be perpetually revolving about the Sun, in orbits which are situated See a Philosophical Account of the Sun in No. XLIII. |