tune, that is the distance of the moon's plane from the sun, added to the degrees of the ascendant.

The influences of the heavenly bodies being determined, it remained only, in each separate case, to observe their positions at some required moment; for upon this, and their aspect to each other, the resolution of any question depended. For this purpose the whole circle of the heavens was distributed into twelve parts or houses, by great circles drawn through the intersection of the horizon and meridian, and cutting the equator in so many equal parts. The first house was placed directly east, and the remainder were counted round in order proceeding to the south according to the motion of the planets. To each of these houses was assigned some peculiar government, according to the scheme below.

The remainder of the art consisted in accurately filling the scheme by an observation, and then framing from it an oracular response.

At the revolution astrology declined; and notwithstanding the labors of the immortal Partridge then, and those of Ebenezer Sibley, which in our own days fill two 4to. volumes, the art may now be considered as exploded.

ASTROLOGY, NATURAL, is the predicting of natural effects from natural causes; as, the changes of weather, winds, storms, hurricanes, thunder, floods, earthquakes, &c. This art properly belongs to physiology, or natural philosophy; and is only to be deduced a posteriori, from phenomena and observations.

ASTROLOMA, in botany; from aspov, a star, and Awua, a fringe, alluding to the five tufts of hair which form a star, near the bottom of the tube of the flower, internally. Brown Prodr. Nov. Holl, v. i. 538. Class and order, pentandria monogynia. Nat. ord. Erica Juss. Epacridea, brown.

Gen. ch. CAL. perianth inferior, permanent, double; inner of five elliptic-lanceolate, acute, equal, erect leaves; outer of four or more, much shorter, concave, imbricated scales: COR. of one petal, tubular; tube twice the length of the calyx,

inflated, furnished on the inside, near the base, with five tufts of soft hairs; limb in five deep, spreading, lanceolate, acute, hairy segments, shorter than the tube. Nectary a cup-shaped undivided gland, surrounding the base of the germen: STAM. filaments five, linear, inserted into the tube, and enclosed within it; anthers oblong, in the mouth of the tube: PIST. Germen superior, roundish, of five cells; style capillary, the length of the tube; stigma 'globose, densely downy :' PERIC. drupa globular, slightly juicy: SEED, nut of five cells, hard and solid, not bursting, with a pendulous oblong kernel in each cell. Ess. ch.: outer calyx of several imbricated leaves: corolla tubular: tube swelling, twice as long as the calyx, with five internal tufts of hair at the base: tube shorter, spreading, bearded: filaments linear, within the tube: drupa almost dry, of five cells. This genus is closely related to stenanthera, as well as to melichrus. We might perhaps unite them all to styphelia. Astroloma consists of shrubs, of humble stature, for the most part decumbent: leaves scattered, often ciliated: flowers axillary, erect. There are six species: 1. A. humifusum, diffuse astroloma; stem prostrate, much branched. Found in various parts of New Holland, on the south-west coast, as well as at Port Jackson and in Van Diemen's island. The remaining five species have all been found in the southern part of New Holland, by Mr. Brown, and apparently by no other botanist. We give their names from his work: 2. A. prostratum, prostrate astroloma; 3. A. denticulatum, toothed astroloma; 4. A. pallidum, pale astroloma; 5. A. compactum, compact astroloma; 6. A. tectum, upright astroloma.

ASTROLUS, in natural history, a name given by authors to a white and splendid stone, small in size, and of a roundish figure, resembling the eyes of fishes.

ASTROMETEOROLOGIA, the art of foretelling the weather, and its changes, from the aspects and configurations of the moon and planets. It is a species of astrology, sometimes called meteorological astrology.

ASTRONIUM, in botany, a genus of the pentandria order, and the diccia class of plants. The male calyx consists of five leaves, and the corolla is quinquepetalous. Of the female the calyx and corolla are the same as in the male; the styli are three, and the seed is single. There is but one species, viz. A. graveolens, a native of Jamaica.

ASTRONOMICAL CALENDAR, an instrument engraved on copper plates, printed on paper, and pasted on a board, with a brass slider carrying a hair: it shows by inspection the sun's meridian altitude, right ascension, declination, rising, setting, amplitude, &c. to a greater degree of exactness than the common globes.

ASTRONOMICAL PLACE of a star, or planet, is its longitude, or place in the ecliptic, reckoned from the beginning of Aries in consequentia, or according to the natural order of the signs.

ASTRONOMICALS, a name used by some writers for sexagesimal fractions; on account of their use in astronomical calculations.

ASTRONOMY, ASTRO NOMICK, ASTRONOM'ICAL, ASTRONO MICALLY, ASTRONOMER, ASTRONOMIZE.

From aσrno, a star, and νομος, a law.

Images astronomically framed under certain constellations to preserve from several inconveniences, as under the sign of the Lion the figure of a lion made in gold, against melancholic fancies, dropsie, plague, fevers. Bp. Hall's Cases of Conscience. Our forefathers, marking certain mutations to happen in the sun's progress through the zodiack, they registrate and set them down in their astronoBrown's Vulgar Errors. The old ascetick Christians found a paradise in a desert, and with little converse on earth, held a conversation in heaven; thus they astronomized in caves; and though they beheld not the stars, had the glory

mical canons.

of heaven before them.

Brown. Chris. Mor. ii. 9.

Astronomers no longer doubt of the motion of the planets about the sun. Locke.

The old and new astronomers in vain
Attempt the heav'nly motions to explain.

Blackmore.

Can he not pass an astronomick line, Or dreads the sun th' imaginary sign; That he should ne'er advance, to either pole? Id. To this must be added the understanding of the globes, and the principles of geometry and astronomy Cowley.

INTRODUCTION.

SECT. I. ETYMOLOGY AND DEFINITION OF
ASTRONOMY.

1. ASTRONOMY, a mixed mathematical science, teaching the knowledge of the celestial bodies; their magnitudes, distances, motions, revolutions, and eclipses: and it comprehends also a knowledge of the natural causes on which all celestial phenomena depend. Hence it is as much a branch of physics as of mathematics, and comprehends the theory of the universe.

SECT. II. HISTORY OF ASTRONOMY. 2. As Astronomy is the most sublime of all the sciences, so it is also the most useful, the most ancient, and, we may add, the most perfect. How can it be otherwise than sublime, when its object is the study of that theatre which our merciful Creator has vouchsafed to establish as an unerring testimony of his existence and his power. Wherever we turn we perceive immensity of operation, guided by the strictest regularity. We find revolutions, intricate and complex, but resolving themselves, by laws irrevocably fixed, into paths the most simple, and the most capable of suffering an increase of numbers without confusion. In another point of view it is sublime: the contemplation of its discoveries and its usefulness would convince the dreary-minded bigot, who sneers at human reason and its efforts, of the amazing extent to which that noblest gift of God to man can be extended. Astronomy is the proudest triumph of philosophy and of human reason. Its superior usefulness when compared with the other sciences can never be opposed by it the navigator is conducted through

unknown seas with safety; and the merchant transports the produce or the surplus of one nation to increase the comforts or relieve the wants of another; in short, it affords the means of intercourse to all the inhabitants of the globe. If, from the folly of mankind, it has sometimes been compelled to effect the transportation of animosity and destruction, it has more frequently assisted the dissemination of arts, civilisation, and happiness. That it is the oldest science we shall more clearly ascertain when we trace, as we shall soon do, its history through the most ancient, and its improvements through the most modern, nations. If then astronomy is possessed of the highest antiquity, the greatest usefulness, and the utmost sublimity, it is an object of the most transcendant worth that can occupy the attention of the human mind.

3. None of the sciences appear to be of higher antiquity than astronomy. From the account given by Moses of the creation of the celestial luminaries, it appears extremely probable that our first progenitor received some knowledge of their nature and uses from his Almighty Creator himself. The Jewish rabbins natural to think that no visible objects would have adopted this opinion: and, indeed, it is more readily excite the curiosity, or appear more worthy of the contemplation of Adam in a state of innocence, than the celestial bodies.

4. Consistently with this, Josephus ascribes to Seth and his posterity a considerable degree of astronomical knowledge. He speaks of two pillars, the one of stone and the other of brick, called the pillars of Seth, upon which were engraved the principles of the science; and he says that the former was still entire in his time. But, be this as it may, it is evident that the great length of the antediluvian lives would afford such excellent opportunities for observing the heavenly bodies, that we cannot but suppose that the science of astronomy must have been considerably advanced before the flood. Josephus says, that longevity was bestowed upon them for the very purpose of cultivating the sciences of geometry and astronomy; observing, that the latter could not be learned in less than 600 years; for that period (he adds) is the grand year.'

6

5. By this remarkable expression is probably meant the period in which the sun and moon come again into the same situation in which they were at the beginning of it, with regard to the nodes, apogee of the moon, &c. This period (says Cassini), of which we find no intimation in any monument of any other nation, is the finest period that ever was invented; for it brings out the solar year more exactly than that of Hipparchus and Ptolemy; and the lunar month within about one minute of what is determined by modern astronomers.' If the antediluvians had such a period of 600 years they must have known the motions of the sun and moon more exactly than their descendants knew them for many ages after the flood. That remarkable expression in the book of Job, in which

equinoctial points, &c. The inhabitants of Japan, of Siam, and of the Mogul's empire, have also been acquainted with astronomy from time immemorial; and the celebrated observatory at Benares is a monument both of the ingenuity of the Hindoos, and of their skill in that science.

15. In the Transactions of the Royal Society of Edinburgh, vol. ii, professor Playfair has given a learned and ingenious dissertation on the astronomy of the Brahmins, in which the great accuracy and high antiquity of the science among them is rendered extremely probable. It appears that their tables and rules of computation have peculiar reference to an epoch, and to observations 3000 or 4000 years A. C. It appears, too, that very considerable mathematical knowledge had been employed in their precepts and calculations. But amongst all these precepts and those calculations, perhaps none will strike the mind of the reader with greater force than the following, from which we shall find, without plucking a leaf from the never-fading laurels of Sir Isaac Newton, that the principle which he developed to the western world, was discovered by the philosophers of the eastern, thousands of years before he existed: of the truth of this the following remarkable passage, translated by Sir William Jones, from the poem of Shirin and Ferhad: there is,' says the author of that poem, " a strong propensity which dances through every atom and attracts the minutest particle to some peculiar object; from such propensity arises every motion perceived in heavenly or terrestrial bodies. It is a disposition to be attracted which taught hard steel to rush from its place and rivet itself on the magnet; it is the same disposition which impels the light straw to attach itself firmly on amber.'

16. We shall conclude this part of the history of Asiatic discoveries in the words of professor Playfair: That observations made in India, when all Europe was barbarous or unininhabited, and investigations into the most subtle effects of gravitation made in Europe near five thousand years afterwards, should thus come in mutual support of one another, is perhaps the most striking example of the progress and vicissitudes of science, which the history of mankind has yet exhibited.'

17. It appears too, that astronomy was not unknown to the Americans; though in their division of time they made use only of the solar and not of the lunar motions. The Mexicans, in particular, had a strange predilection for the number thirteen: their shortest periods consisted of thirteen days; their cycle of thirteen months, each containing twenty days; and their epoch of four periods of thirteen years each. This excessive veneration for the number thirteen arose, according to Siguenza, from its being the number of their greater gods. Clavigero also asserts it as a fact, that having discovered the excess of a few hours in the solar above the lunar year, they made use of intercalary days to bring them to an equality, as was done by Julius Cæsar in the Roman calendar-but with this difference, that instead of one day every four years, they interposed thirteen days every tifty-two years.

18. Among the ancients we find the name of Chaldean used often for astronomer or astrologer. Indeed both these nations pretended to a very high antiquity, and claimed the honor of producing the first cultivators of this science. The Chaldeans boasted of their temple or tower of Belus, and of Zoroaster, whom they placed 5000 years before the destruction of Troy; while the Egyptians boasted of their colleges of priests, where astronomy was taught, and of the monument of Osymandias, in which, it is said, there was a golden circle of 365 cubits in circumference, and one cubit thick, divided into 365 equal parts, according to the days of the year, &c. It is indeed evident that both Chaldea and Egypt were countries very proper for astronomical observations, on account of the extended flatness of the country, and the purity and serenity of the air. The tower of Belus, or of Babel itself, was probably an astronomical observatory; and the pyramids of Egypt, whatever they were originally designed for, might perhaps answer the same purpose; at least they show the skill of this people in practical astronomy, as they are all placed with their four fronts exactly facing the cardinal points of the compass.

19. The Chaldeans began to make observations soon after the confusion of languages, as appears from the observations found by Alexander on the taking of Babylon; and it is probable they began much earlier. They determined, with tolerable exactness, the length both of a periodical and synodical month. They discovered that the motion of the moon was not uniform; and they even attempted to assign those parts of the orbit in which the motion is quicker or slower. We are assured by Ptolemy that they were not unacquainted with the motion of the moon's apogee and nodes, the latter of which they supposed made a complete revolution in 65854 days, or a little more than eighteen years, and contained 223 complete lunations, which period is called the Chaldean Saros.

20. Ptolemy also gives us from Hipparchus several observations of lunar eclipses made at Babylon above 720 years A. A. C.; and Aristotle informs us that they had many occultations of the planets and fixed stars by the moon; a circumstance which led them to conceive that eclipses of the sun were to be attributed to the same cause. They had also no inconsiderable share in arranging the stars into constellations, and the comets did not escape their observation. Dialling was also practised among them long before the Greeks were acquainted with that science.

21. The Egyptians were much of the same standing in astronomy with the Chaldeans. Herodotus ascribes their knowledge in the science to Sesostris; but probably not the same whom Newton makes contemporary with Solomon, as they were acquainted with astronomy at least many hundred years before that era. We learn from the testimony of some ancient authors, that they believed the figure of the earth was spherical; that the moon was eclipsed by passing through the earth's shadow, though it does not certainly appear that they had any knowledge of the true system of the universe; that they attempted to measure the magnitude of the earth and sun,

though their methods of ascertaining the latter were very erroneous; and that they even pretended to foretel the appearance of comets, as well as earthquakes and inundations. This science, however, gradually decayed, and in the time of Augustus it was entirely extinct among them.

22. Astronomy passed from Chaldea and Egypt to the Phoenicians, and was applied by that commercial people to the purposes of navigation; and they, in consequence, became masters of the sea, and of almost all the commerce in the world. The Greeks, it is probable, derived their astronomical knowledge chiefly from the Egyptians and Phoenicians, by means of several of their countrymen who visited these nations for the purpose of learning the different sciences. Newton supposes that the division into constellations was made about the time of the Argonautic expedition; but it is probable that most of them were of a much older date, and derived from other nations, though clothed in fables of their own invention.

23. The fable of Atlas supporting the heavens upon his shoulders, shows that some Mauritanian monarch of that name had made considerable advances in astronomical knowledge; and his discoveries had probably been communicated to the Greeks. Several of the constellations are mentioned by Hesiod and Homer, who lived about A. A. C. 870. Their knowledge in this science however, was greatly improved by Thales the Milesian, and other Greeks, who travelled into Egypt, and brought from thence the chief principles of the science. Thales was born about A. A. C. 640, and he was the first among the Greeks who observed the stars, the solstices, and predicted the eclipses of the sun and moon.

24. The science was farther cultivated and extended by his successors Anaximander, Anaximenes, and Anaxagoras; but especially by Pythagoras, who, about A. A. C. 577, brought from Egypt the learning of these people, taught it in Greece and Italy, and founded the sect of the Pythagoreans. He taught that the sun was in the centre of the universe; that the earth was round; that there were antipodes; that the moon reflected the rays of the sun, and was inhabited like the earth; that comets were a kind of wandering stars, disappearing in the further parts of their orbits; that the white color of the milky way was owing to the united brightness of a great multitude of small stars; and he supposed that the distances of the moon and planets from the earth, were in certain harmonic proportions to one another.

25. Philolaus, a Pythagorean, who flourished about A. A. C. 450, and asserted the diurnal motion of the earth on its own axis, was taught by Hicetas, a Syracusan. About the same time Meton and Euctemon flourished at Athens, where they observed the summer solstice, A. A. C. 432, with the risings and settings of the stars, and what seasons they answered to. Meton also invented the cycle of nineteen years, which still bears his name.

26. Eudoxus, of Cnidos, lived about A. A. C. 370, and was one of the most skilful astronomers and geometricians of antiquity, and the supposed inventor of many of the propositions in Euclid's

Elements. He introduced geometry into the science of astronomy, and travelled into Asia, Africa, Sicily, and Italy, to improve it: and we are informed by Pliny, that he determined the annual year to contain 365 days 6 hours, and also the periodical time of the planets, and made other important discoveries and observations. Calippus flourished soon after Eudoxus, and his celestial sphere is mentioned by Aristotle; but he is better known by a period of seventy-six years which he invented, containing four corrected Metonic periods, and which commenced at the summer solstice, A. A. C. 330. About this time the knowledge of the Pythagorean system was carried into Italy, Gaul, and Egypt, by certain colonies of Greeks.

27. Vitruvius, however, represents the introduction of astronomy into Greece, in a manner somewhat different. He maintains that Berosus, a Babylonian, brought it immediately from Babylon itself, and opened an astronomical school in the isle of Cos. And Pliny says, that, in consideration of his wonderful predictions, the Athenians erected a statue to him in the gymnasium, with a gilded tongue. But if this Berosus be the same with the author of the Chaldaic histories, he must have lived before Alexander. About this time, or rather earlier, the Greeks having begun to plant colonies in Italy, Gaul, and Egypt, became acquainted with the Pythagorean system, and the notions of the ancient druids concerning astronomy. Julius Cæsar informs us that the latter were skilled in this science; and that the Gauls in general were able sailors, which they could not be without a competent knowledge of astronomy; and it is related of Pytheas, who lived at Marseilles in the time of Alexander the Great, that he observed the altitude of the sun at the summer solstices by means of a gnomon. He is also said to have travelled as far as Thule to settle the climates.

28. After Alexander's death the sciences flourished chiefly in Egypt, under the auspices of Ptolemy Philadelphus, and his successors. He founded a school there, which continued till the invasion of the Saracens, A. A. C. 650. From the founding of that school, the science of astronomy advanced considerably. Aristarchus, about A. A. C. 270, strenuously asserted the Pythagorean system, and gave a method of determining the sun's distance by the dichotomy of the moon.-Eratosthenes, who was born at Cyrene A. A. C. 271, measured the circumference of the earth by a gnomon; and being invited to Alexandria, from Athens, by Ptolemy Euergetes, and made keeper of the royal library there, he set up for that prince those armillary spheres, which Hipparchus and Ptolemy the astronomer afterwards employed so successfully in observing the heavens. He also determined the distance between the tropics to be of the whole meridian circle, which makes the obliquity of the ecliptic in his time to be 23° 51′.

29. The celebrated Archimedes, too, cultivated astronomy, as well as geometry and mechanics, determined the distances of the planets from one another; and constructed a kind of planetarium or orrery, to represent the phenomena and motions of the heavenly bodies.