ASTROLUS, in natural hiftory, a name given by authors to a white and fplendid stone, fmall in fize, and of a roundish figure, refembling the eyes of fishes. ASTROMETEOROLOGIA, the art of foretelling the weather, and its changes, from the afpects and configurations of the moon and planets. This makes a fpecies of aftrology, diftinguithed by fome under the denomination of meteorological aftrology. ASTRONIUM, in botany: A genus of the pentandria order, belonging to the diœcia class of plants. The male calyx confifts of five leaves, and the corolla is quinquepetalous: Of the female the calyx and corolla are the fame as in the male; the ftyli are three, and the feed is tingle. There is but one fpecies, viz. ASTRONIUM GRAVEOLENS, a native of Jamaica. * ASTRONOMER. n. J. [from go, a ftar, and, a rule or law.] One that studies the celettial motions, and the rules by which they are governed.→→The motions of factions under kings, ought to be like the mctions, as the fironomers speak of, in the inferiour orbs. Bacon. * ASTRONOMICAL. ASTRONOMICK. adj. [from afronomy.] Belonging to altronomy.→→ Our forefathers marking certain mutations to hap pen in the fun's progrefs through the zodiaci, they registrate and fet them down in their allo mical canons. Brown. ASTRONOMICAL CALENDAR, an inftrument graved on copper plates, printed on paper, and pafted on a board, with a brass flider carrying hair; it thows by infpection the fun's meridian titude right afcenfion, declination, rifing, lettin amplitude, &c. to a greater degree of exacinos than the common globes. ASTRONOMICAL PLACE of a ftar or planet, its longitude or place in the ecliptic, reckoned from the beginning of Aries in confequentia, cording to the natural order of the highs. ASTRONOMICAL SECTOR, a very feful mate matical inftrument, made by the late ingenio Mr Graham; a description of which is give the courfe of the article ASTRONOMY. ASTRONOMICALS, a name ufed by ka writers for fexagefimal fractions; on account their ufe in attronomical calculations. * ASTRONOMICALLY, adv. [from «fire mical.) In an aftronomical manner. * ASTRONOMICK. See ASTRONOMICAL ASTRONOMICUS RADIUS. See RADIUS ASTRONOM Y. INTRODUCTION. SECT. I. ETYMOLOGY and DEFINITIONS of A STRONOMY. asov, and, a law, or the most fimple, and the most capable of fuffer another point of view it is fublime: the center an increate of numbers without confution! plation of its difcoveries and its usefulmefs, wo (1.) * ASTRONOMY. ». f. [s, from human reafon and its efforts, of the almo rule.] A mixed mathematical fcience, teaching mitable extent, to which that nobleft gift of G the knowledge of the celestial bodies; their mag- to man can be extended. Aftronomy is the nitudes, motions, diftances, periods, eclipfes, and umph of philofophy and of human reason! Is order. Pythagoras taught that the earth and pla- fuperior ufefulnets when compared with the nets turn round the fun, which ftands immoveable fciences can never be oppofed; by it the naviest is conducted through unknown feas with a by it the merchant tranfports the produce (2.) ASTRONOMY comprehends alfo, a know- or relieve the wants of another; in that it furplus of one nation, to increafe the rece ledge of the natural caufes on which all the phe- an intercourie to all the inhabitants of the g nomena of the heavenly bodies depend: and in If, from the folly of mankind, it has forme this view, it is as much a branch of phyfics as of been compelled to effect the tranportation in the centre. To this must be added the un derftanding of the globes, and the principles of geometry and aftronomy. Coavley. mathematics, and comprehends the theory of the whole univerfe. SECT. II. HISTORY of ASTRONOMY. (3.) AS ASTRONOMY is the moft fublime of all freque molity and deftruction, it has more fifted the diffemination of arts and civiliz for thofe ready for fuch recourfes.-That it is oldeft fcience we shall more clearly afcertain, w we trace, as we fhall foon do, its hiftory toro. the Sciences, fo it is alfo the moft ufeful, and we the moft ancient, and its improvements, three may with equal veracity, add, that it is the moft the most modern nations.-If then aftrorcy ancient. How can it be otherwife than fublime, poffeffed of the highest antiquity, the greatell when its object is the ftudy of that theatre which fulness and the utmoft fublimity, it becomes t our merciful creator has vouchsafed to eftablish, as object the moft tranfcendently worthy of the p an unerring teftimony of his exitience and of his power; wherever we turn ourfelves we encounter immenfity of operation, guided by the ftricteft re rations of the HUMAN MIND! er antiquity than aftronomy. From the act (4.) None of the sciences, appears to be of gularity! which ever way we view it, we find re- given by Mofes, of the creation of the cl volutions, intricate and complex, but refolving luminaries, it appears extremely probable, a themselves by laws irrevocably fixed, into paths our firit progenitor received fome knowleder their nature and ufes from his Almighty Creator himfelf. The Jewith Rabbins have adopted this opinion: and, indeed, it is natural to think that no vilible objects would more readily excite the curiofity, or appear more worthy of the contemnplation of ADAM in a ftate of innocence than the cæleftial bodies. (5.) Confiftently with this, Jofephus afcribes to SETH and his posterity, a confiderable degree of aftronomical knowledge. He speaks of two pillars, the one of ftone, and the other of brick, called the pillars of Seth, upon which they engraved the principles of the fcience; and he fays that the former was ftill entire in his time. But be this as it may, it is evident that the great length of the antediluvian lives would afford fuch excellent opportunities for obferving the heavenly bodies, that we cannot but fuppofe that the fcience of aftronomy was confiderably advanced before the flood. Jofephus fays, that longevity was bestowed upon them, for the very purpofe of cultivating the fciences of geometry and aftronomy; obferving, that the latter could not be learned in lefs then 600 years; “for that period, he adds, is the grand year." (6.) By this remarkable expreffion, is probably meant, the period in which the fun and moon come again into the fame fituation in which they were at the beginning of it, with regard to the nodes, apogee of the moon, &c. "This period Tays Caffini, of which we find no intimation in any monument of any other nation, is the fineft period that ever was invented; for it brings out the folar year more exactly than that of Hipparchus and Ptolemy; and the lunar month within about one minute of what is determined by modern aftronomers?" If the Antediluvians had fuch a period of 600 years, they must have known the motions of the fun and moon, more exactly, than their defcendants knew them, for many ages after the flood. (7.) Indeed, befides the motives of mere curiofity, which of themselves may be supposed, to have excited people to a contemplation of the glorious celestial canopy, as far as that was pofible, it is eafily to be feen, that fome parts of the science answer fuch effential purposes to mankind, that they could not long be poflibly difpenfed with. And it has been remarked, that traces of this fcience in different degrees of improvement, have been found among all nations. (8.) Upon the building of the Tower of Babel, it is fuppofed that Noah retired with his chidren born after the flood, to the north-eaftern part of Afia, where his defcendants peopled the vaft empire of China. It is faid alfo, that the Jefuit milionaries have found traditional accounts among the Chinese, of their having been taught this fcience, by their first emperer Fo-hi, who is fuppofed to be the fame with Noah; and Kempfer afferte, that Fo-hi difcovered the motions of the heavens, divided time into years and months, and invented the 12 figns, into which they divide the zodiac, and which they diftinguith by the following names; 1, the moufe; 2, the ox or cow; 3, the tiger; 4, the hare; 5, the dragon: 6, the erpent: 7, the horse; 8, the sheep; 9, the mon key; 10, the cock or hen; 11, the dog and 12, the boar. They divide the heavens into 28 conftellations, or claffes of stars, allotting 4 to each of the 7 planets; fo that the year always begins with the fame planet; and their conftellations anfwer to the 28 lunar manfions used by the Arabian aftronomers. (9.) Thefe conftellations, however, they do not mark with the figures of animals, like moft other nations, but by comcting the stars by ftraight lines, and denoting the ftars themselves by fmall circles: fo, for inftance, the great bear would be marked as represented in Plate XXVIII. Fig. 10. (to) The Chinese themfelves have, many records of the high antiquity of their aftronomy: though not without fufpicions of great mistakes. They afcribe the difcovery of the pole itar, the invention of the fphere, and mariner's compass, &c. to their emperor Hong-Ti, the grandion of Noah. But on more certain authority, it is afferted by Gaubil, that at leaft 120 years before Christ, the Chinese had determined by obfervation the number and extent of their conftellations as they now ftand; the situation of the fixed stars with respect to the equinoctial and folftitial points;" and the obliquity of the ecliptic, with the theory of eclipfes; and that they were, long before that, acquainted with the true length of the folar year, the method of obferving meridan altitudes of the fun, by the fhadow of a gnomon, and of deducing from thence his declination, and the height of the pole. (11.) The fame mifionary alfo fays, that the Chinese have yet remaining, fome books of aftronomy, which were written about 200 years before Chrift; from which it appears, that the Chinefe knew the daily motion of the fun and moon, and the time of the revolutions of the planets, many years before that period. Du Halde informs us, that Tcheou-cong, the moft skilful d ftronomer that ever China produced, lived more than a thousand years before Chrift: that he palled whole nights in observing the celestial bodies, and arranging them into constellations, &c. At prefent, however, the flate of aftronomy is but very low in that country, although it is cultivated at Peking, by public authority, in like manner as in moft of the capital cities of Europe. This is afcribed, by Dr Long, to a barbarous decree of one of their emperors, to burn all the books in the empire, excepting fuch as related to agriculture and medicine. (12.) Aftronomy, according to Porphyry, muft have been of very ancient ftanding in the Eat. He informs us that when Babylon was taken by Alexander, there were brought from thence, celeftial obfervations for the pace of 1903 years; which therefore must have commenced within 115 years after the flood, or within 15 years atter building of Babel. Epigenes, according to Pliny, affirmed that the Babylonians had obfervations of 720 years, engraven on bricks. (13.) Achilles Tatius afcribes the invention of aftronomy to the Egyptians; and adds that their knowledge of that Rience was engraven on pillars, and by that means tranfmitted to pofterity BATULY, in his elaborate rhiftory of ancient and modern Antronomy, ensicavours to trace the ori gin of this science among the Chaldeans, Egyptians, Persians, Indians, and Chinese, to a very early period. And thence he maintains, that it was cultivated in Egypt and Chaldea, 2800 years before Chrift; in Perfia, 3209: in India, 3101; and in China, 2952 years before that æra. He alfo apprehends, that aftronomy had been ftudied even long before this liftant period, and that we are only to date its revival from thence. (14.) M. BAILLY, in investigating the antiquity and progrefs of aftronomy among the Indians, examines and compares four fets of aftronomical Tables of the Indian philofophers, viz. that of the Siamefe, explained by M. Caflini in 1689; that brought from India, by M. le Gentil, of the Academy of Sciences; and two other manufcript tables, found among the papers of M. de Life: all of which agree together, and refer to the me. ridan of Benares. It appears, that the fundamental epoch of the Indian aftronomy, is a conjunction of the fun and moon, which took place at the diftance of 3102 A. A. C. And M. Bailly computes that fuch a conjunction really then happened. (15.) He farther obferves, that, at prefent, the Indians calculate eclipfes, from obfervations made 5000 years ago; the accuracy of which, with regard to the folar motion, far exceeds that of the beft Grecian aftronomers. The lunar motions have been computed from the space through which that luminary passes in 1,600,984 days.They alfo ufe the cycle of 19 years, the fame as that afcribed by the Greeks to Meton. Their theory of the planets is better than that of Ptolemy, as they do not fuppofe the earth in the centre of the celeftial motions, and believe that Venus and Mercury move round the fun. Their aftronomy alfo agrees with the most modern difcoveries, with regard to the obliquity of the ecliptic, and the acceleration of the equinoctial points, &c. The inhabitants of Japan, of Siam, and of the Mogul's 'empire, have alfo been acquainted with aftronomy, from time immemorial; and the celebrated obfervatory at Benares, is a monument both of the ingenuity of the Hindoos, and of their skill in that fcience. (16) In the Tranfactions of the Royal Society of Edinburgh, vol. ii. Profeffor PLAYFAIR has given a learned and ingenious differtation on the aftronomy of the Bramins, in which the great accuracy and high antiquity of the fcience among them is rendered extremely probable. It hence appears, that their tables and rules of computation have peculiar reference to an epoch, and to obfervations 3000 or 4000 years A. C. Other inftances are there given of the very confiderable degree of mathematical knowledge, employed in their precepts and calculations. But amongst all thefe precepts and thofe calculations, perhaps none will ftrike the mind of the reader with greater force than the two following; in the firft of which we fhall find, without plucking a leaf from the never fading laurels of Sir 1. Newton, that that immortal principle which he developed to the Weftern world, was difcovered by the Philofophers of the Eaftern, thousands of years before he exifted; and in the fecond the ring of Saturn is ex hibited to us by them, perhaps about the fame time, anterior to its discovery by Huygens. Ot the first we have a remarkable paffage, tranflated by Sir W. Jones form the Poem of Shirin and Fer had: "there is," fays the author of that poem "a trong propenfity which dances through every atom and attracts the minuteft particle to fome p culiar object; from fuch propenfity arifes every motion perceived in heavenly or terreftrial bodies; it is a difpofition to be attracted which taugh hard steel to rush from its place, and rivet itki on the magnet, it is the fame difponition whic impels the light ftraw to attach itfelf firmly ca amber." As to the Ring of Saturn, their Go Sani, who reprefents that planet surrounded by ferpent, is too confpicuous not to be immediate recognized. (17.) We fhall conclude this part of the Hi of Aliatic difcoveries in the words of Profe Playfair. "That obfervations made in India when all Europe was barbarous or uninhabited, inveftigations into the most subtle effects of gravita tion, made in Europe near five thousand years terwards, thould thus come in mutual fupport one another, is perhaps the moft ftriking example of the progrefs and vifficitude of Science, which the Hiftory of mankind has yet exhibited." (18.) It appears too, that aftronomy was t unknown to the Americans; though in their d vifion of time, they made ufe only of the fola, and not of the lunar motions. The Mexicans, in particular, had a strange predilection for the number 13: their fhorteft periods confifted of 1: days; their cycle of 13 months, each containing 20 days; and their century of 4 periods of 1 years each: this exceffive veneration for the nu ber 13, arofe, according to Siguenza, from its be ing the number of their greater gods. Claviers alfo afferts it as a fact, that, having difcovered the excess of a few hours in the folar, above the lunar year, they made use of intercalary days, ta bring them to an equality, as was done by Ja us Cæfar in the Roman calendar; but with this difference, that inftead of one day every 4 years they interpofed 13 days every 32 years. (19.) Thus have we introduced a people who pretenfions to priority of difcovery may wa difpute with thofe of the Chaldeans and Egyp ans; but we will ftate the claims of the two af, and let our readers judge for themfelves. Amo the Ancients we find the name of Chaldean tes often for aftronomer or aftrologer. Indeed bu thefe nations pretended to a very high antiqui and claimed the honour of producing the firical tivators of this fcience. The Chaldeans boards their temple or tower of Belus, and of Zoroates, whom they placed scoo years before the dre tion of Troy; while the Fgyptians boased f their colleges of priests, where aftronomy wa taught, and of the monument of Olyandyas, which, it is faid, there was a golden circle of cubits in circumference, and one cubit thick, vided into 365 equal parts, according to the days of the year, &c. It is indeed evident that by Chaldea and Egypt were countries very prop for aftronomical obfervations, on account of th extended flatnefs of the country, and the p and ferenity of the air. The tower of Belus, or of Babel itfelf, was probably an aftronomical obfrvatory; and the pyramids of Egypt, whatever they were originally defigned for, might perhaps antiver the fame purpose; at least they flew the kill of this people in practical attronomy, as they are all placed with their four fronts exactly facing the cardinal points of the compaís. (10.) The Chaldeans began to make obferva tions foon after the confufion of languages, as appears from the obfervations found there on the taking of Babylon by Alexander; and it is probable they began much earlier. They determined, with tolerable exactncis, the length both of a periodical and fynedical month. They difcovered, that the motion of the moon was not uniform; and they even attempted to affan thofe parts of the orbit in which the motion is quicker or flower. We are affured by Ptolemy that they were not unacquainted with the motion of the moon's apogee and nodes, the latter of which they fupp fed mude a complete revolution in 6583 days, or a little more than 18 years, and contained 223 comp'te lunations, which period is called the Chaldean SAROS. (11.) PrOLI MY alfo gives us from Hipparchus, feveral obfervations of lunar ecliples made at Babylon above 720 years A. C. and Ariftotle informs us, that they had many occultations of the planets and fixed fars by the moon; a circumftance which led them to conceive that eclipfes of the fun were to be attributed to the fame caufe. They had alfo no inconfiderable fhare in arranging the tors into conftellations, and the comets did not cape their obfervation. Dialling was alfo practifed among them long before the Greeks were acquainted with that feience. (22.) The Egyptians were much of the fame ftanding in Aftronomy with the Chaldeans. Herodotus afcribes their knowledge in the feience to Seioftris; but probably not the fame whom Newton makes cotemporary with Solomon, as they were acquainted with aftronomy at leaft many hundred years before that æra. We learn, from the teftimony of fome ancient authors, that they believed the figure of the earth was fpherical; That the moon was eclipfed by paffing through the earth's fhadow, though it does not certainly appear that they had any knowledge of the true fyftem of the univerfe; that they attempted to measure the magnitude of the earth and fun, though their methods of afcertaining the latter Were very erroneous; and that they even pretendel to foretel the appearance of comets, as well as Garthquakes and inundations. This feience, how ever, gradually decayed, and in the time of AuLuftus it was entirely extinct among them. (23.) Aftronomy paffed from Chaldea and Egypt to the Phoenicians, and was applied by that commerical people, to the purpofs of navigation, fcering their courfe by the north polar ftar. They became adventrous in their voyages, and quit ting the fhores, fteered their courfe by one of the fats in the urfa minor or little Bear, which being nereft to that point in the Heavens called the pole, is the guide of the prefent navigator. Other nations attracted by brilliancy rather than by ufefulLefs, reckoned their courfe by the urfa major or VOL. II. PART II. great Bear, which from its changeablenefs could not direct them in long voyages; and from this caufe they never ventured from Land." Thus the Phoenicians became mafters of the fea, and of almost all the commerce in the world. The Greeks, it is probable, derived their attronomical knowledge chicily from the Egyptians and Phoenicians, by means of feveral of their countrymen whovffits ed thefe nations, for the purpose of learning the different iciences. Newton fuppofes that the divilion into conftellations was made about the time of the Argonautic expedition; but it is more probable that they were, at leaft moft part of them, of a much older dite, and derived from other nations, though clothed in fables of their own invention or application. (24.) The fable of ATLAS fupporting the heaveus upon his fhoulders, flows that fome Mauri tanian menarch of that name had made confiderable advances in aftronomical knowledge; and his difcoveries had probably been communicated to the Greeks. Several of the conftellations are mentioned by Heliod and Homer, who lived about A. A. C. 87c. Their knowledge in this fcience however was greatly improved by Thales the Milefian, and other Greeks, who travelled into Egypt, and brought from thence the chief principles of the fcience. Thales was born about A. A. C. 640, and he was the first among the Grecks, who obferved the ftars, the folftices, and predicted the eclipfes of the fun and moon. (25.) The fcience was farther cultivated and extended by his fucceffors Anaximander, Anaximenes, and Anaxagoras; but efpecially by Pythagoras, who, about A. A. C. 577, brought from Egypt the learning of thefe people, taught it in Greece and Italy, and founded the fect of the Pythagorears. He taught that the fun was in the centre of the univerfe; that the earth was round; that there were antipedes; that the moon reflected the rays of the fun, and was inhabited like the earth; that comets were a kind of wandering ftars, difappearing in the further parts of their orbits; that the white colour of the milky way was owing to the united brightnefs of a great multitude of fmall ftars; and he fuppofed that the diftances of the moon and planets from the carth, were in certain harmonic proportions to one another. (16.) PHILOLAUS, a Pythagorean, who florrifled about A. A. C. 450, and allerted the annual motion of the earth on her own axis, was taught by licetas, a Syracufan. About the fame time Meton and Euftemon, flourished at Athens, where they obferved the fummer folftice, A. A. C. 432. with the rifings and fettings of the ftare, and what feafons they aufwered to. Meton alfo invented the cycle of 19 years, which it bears his name. (27.) EUDOXU's, of Chides, lived about A. A. C. 370, and was one of the moft skilful aftronomers and geometricians of antiquity, and the inventor of many of the propofitions in Euclid's Elements. He introduced geometry into the fcience of aftronomy, and travelled into Afia, 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 alfo the periodical time. of the planets, and made other important difcoMmm m veries veries and obfervations. Calippus flourished foon after Eudoxus, and his celeftial fphere is mention ed by Ariftotle; but he is better known by a period of 76 years which he invented, containing 4 corrected Metonic periods, and which commenced at the fummer solstice, A. A. C. 330. About this time the knowledge of the Pythagorean fyftem was carried into Italy, Gaul, and Egypt, by certain colonies of Greeks. (28.) VITRUVIUS, however, reprefents the introduction of aftronomy into Greece, in a manner fomewhat different. Ile maintains, that Berofus, a Babylonian, brought it immediately from Babylon itfelf, and opened an aftronomical school in the ifle of Cos. And Pliny fays, that in confideration of his wonderful predictions, the Athenians erected a ftatue to him in the gymnafium, with a gilded tongue. But if this Berofus be the fame with the author of the Chaldaic hiftories, he must have lived before Alexander. About this time, or rather earlier, the Greeks having begun to plant colonies in Italy, Gaul, and Egypt, thefe became acquainted with the Pythagorean fyftem, and the notions of the ancient Druids concerning aftrono. my. Julius Cæfar informs us that the latter were fkilled in this fcience; and that the Gauls in general were able failors, which at that time they could not be without a competent knowledge of aftronomy: and it is related of PYTHOAS, who lived at Marseilles in the time of Alexander the Great, that he obferved the altitude of the fun at the fummer folftice by means of a guomon. He is alfo faid to have travelled as far as Thule to fettle the climates. (29., After Alexander's death, the fciences flourished chiefly in Egypt, under the aufpices of Ptolemy Philadelphus, and his fucceffors. He founded a school there, which continued till the invasion of the Saracens, A. A. C. 650. From the founding of that fehool, the fcience of aftronomy advanced confiderab y. Ariftarchus, about A. A. C. 270, ftrenuously alerted the Pythagorean fyftem, and gave a method of determining the fun's diftance by the dichotomy of the moon.-Eratof thenes, 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 fet up for that prince thofe armillary fpheres, which Hipparchus and Ptolemy the aftronomer afterwards employed to fuccefsfully in obferving the heavens. He alfo 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′3 (30.) The celebrated ARCHIMEDES, too, cultivated aftronomy, as well as geometry and mechanics; determined the distances of the planets from one another; and constructed a kind of planetarium or errery, to reprefent the pheonniena and motions of the heavenly bodies. (31.) Not to mention many others of the ancients, who cultivated attronomy, HIPPARCHUS, who flourished about A. A C. 145, was the first who app ied himself to the ftudy of every branch of that science. Ptolemy fays, he made great inprovements in it; he ditcovered that the orbits of the planets are eccentric, that the moon moved flower in her apogee than in her perigee, and th there was a motion of anticipation of the moon nodes: he conftructed tables of the motions of the fun and moon, colle&ted accounts of fuch :clipfes, &c. as had been made by the Egyptia and Chaldeans, and calculated all that wer happen for 600 years: he discovered that the f. ed itars changed their places, having a flow me tion of their own from W. to E. he corrected : Calippic period, and pointed out some errors Eratofthenes's method for meafuring the circum rence of the earth; he computed the fun's diftan more accurately than his predeceffors: but beft work is a catalogue of the fixed stars, to t number of 1022, with their longitudes, latitudes and apparent magnitudes; which, with mot e his other obfervations, are preferved by Ptole in his Almageft. (་་ (32) From the time of Hipparchus, till that Ptolemy, little progrefs was made in aftronor He was born at Pelufium in Egypt, in the century, and made the greatest part of his obfer vations at the celebrated school of Alex indr that country. Profiting by thofe of Hippard. and other ancient aftronomers, he formed tem of his own, which, though erroneous, was implicitly followed for many ages by all natiers He compiled a great work, called the Alma which contained the obfervations and collect of his predeceffors in aftronomy. This work w preferved from the conflagration of the Al drian library by the Saracens, and tranflated Arabic, A. D. 827, and into Latina 1230. The Greek original was not known in Europe til o beginning of the 15th century, when it brought from Conftantinople, then taken by Turks, by George, a monk of Trapezord, be whom it was tranflated into Latin; and vant other editions have been fince made. (33.) From A. D. 8co, till the beginning of t 14th century, the western parts of Europe with immerfed in grofs ignorance, while the Arab profiting by the books they had preserved for the wreck of the Alexandrian library, cultivat and improved all the fciences, and particu. 2* that of aftronomy, in which they had many profeffors and authors. The caliph AL MANSUR first introduced a tafte for the fciences into ! empire. His grandfon AL MAMUN, who c ed the throne in 8:4, was a great encourager improver of the fciences, efpecially of aftrural Having conftructed proper inftruments, he ma many obfervations; determined the obliquis f the ecliptic to be 23° 35'; and under his aut a degree of the circie of the earth was meafired fecond time in the plain of Singar, on the bud of the Red Sea. (34) About this time ALFERGANUS WHOĆE CAN ments of aftronomy; and Albategnius, whole thed about the year 380, greatly reformed n, ! comparing his own obfervations with the Ptolemy. Hence he computed the motion os 12fur's apogee from Ptolemy's time to his os fettled the preceflion of the equinoxes at cnc de gree in 70 years; and fixed the obliquity o ecliptic at 23° 35'. The tables which he comp fed, for the meridian of Araćta, were long efter ed by the Arabians. |