As to the Indians and Chinese, there is no doubt but that they cultivated astronomy at a I very early period, and that the Brahmins of the former people, being altogether devoted to. speculative sciences, made advances in that of astronomy equal to any of the nations of an tiquity. M. Bailly informs us, in his history, that he examined and compared four different sets of astronomical tables of the Indian phi. losophers, namely, that of the Siamese explain ed by M. Cassini in 1689 ; that brought from India by M. le Gentil, of the Academy of Sci ences, and two other manuscript tables, found among the papers of the late M. de Lisle ; all of which he found to accord with one another, referring to the meridian of Be,nares. It ap pears that the Indians date their astronomy from a remarkable conjunction of the sun and moon, which took place at the distance of 302 years before Christ ; and M. Bouilly concludes that, from our most accurate astronomical ta bles, such a conjunction did take place. The Indians calculate eclipses by the mean motions of the sun and moon, commencing at a period five thousand years distant ; but, without giv ing them credit for an antiquity which is at variance with all historical documents, sacred and profane, it suffices here to observe that they have adopted the cycle of nineteen years, and that their astronomy agrees with modern discoveries in many particulars, as to the obli quity of the ecliptic, and an acceleration of the motion of the equinoctial points. They also assign inequalities to the motions of the planets, answering very well to the annual parallax, and the equation of the centre.
The Greeks, without doubt, derived their astronomical knowledge from the Egyptians and Phoenicians by means of several of their countrymen, particularly Tildes the Milesiany who, about 640 years before Christ, travelled into Egypt, and brought from thence the chief principles of the science. lie was the first among the Greeks who observed the stars, the solstices, the eclipses of the sun and moon, and proceeded so far as to predict an eclipse of the sun. It appears, however, that, before his time, many of the constellations were known, for we find mention of them in Hesiod and Homer, two of their earliest writers. After Thales, Anaximander, Anaximenes, Anaxago ras, but above all, Pythagoras, distinguished themselves among the number of those who cultivated astronomy. The latter, after having resided a long time in Egypt and other foreign parts, established a sect of philosophers in his owe country, known by the name of cans. He taught, among other things, that the sum was in the centre of the universe and immoveable; that the earth was round, and .he inhabitants were antipodes to each other ; that the moon reamted the rays of the sun, and was inhabited like the earth ; that comets were wandering stars ; that the milky way was an assemblage of which derived its wbute colour foam the brightness of their fight, be sides a numbs. of other particulars, some ol which are admitted in the present day. Phi Jokes, a Pythagorean, the dadrine of the mash's motion round the sun, 450 years before Christ, and Ricotta, a Syraeosan, taught, a hundred. years after, the diurnal mo tion of the earth on its own axis ; also Moon, the inventor of the hietonic cycle, and Eucto mon, observed the summer solstice 432 years before Christ, besides the risings and the stars, and what seasons they answered to. The same subject was treated of at large by Anuses in his poem entitled Phenomena. Eratastheaes, a Cyrenian, who was born in 271 a. c. measured the circumference of the
earth ; and, being invited to the court of Ptole my Evergetes at Alexandria, he was made keeper of the royal library, and set up there the armillary which Hipparchus and Ptolemy afterwards toed so effectually. He also determined the distance between the tra! pica to be 11-S3 of the whole meridian circle, which makes the obliquity of the ecliptic in his time to be 23 degrees 51 minims and one third. Archimedes is said to have constructed a planetarium to represent the and motions of the heavenly bodies ; and many others added to the stock of astronomical knowledge, but none ao much as Hipparchris, who flourished about 140 years a. c. and sur passed all that had gone before him in the ex tent of his researches. lie showed that the or bits of the planets were eccentric, and that the moon moved slewer-in her than in her perigee. He constructed of the motions of the sun and moon; collated accountsofeclip. errs that had been computed by the Clialdems and Fey, ptians ; andcalculadea such as would happen for six hundred years to come; beside correcting the errors of Eratosthems in his measurement of the earth's circumference, and computing the sun's distance tore accurately. He is, however, most thstingoished by his catalogue of the fixed stars to the neater of a thousand and twenty-two, with their latitudes and longitudes, and apparent magnitudes. These, and mom other of his observations, are preserved by his illnotriout successor Ptolemy. Prom the time of Hipparchus to that of Ptolemy, an interval of upwards of two cen turies, few or no advances were made in troncany. Claudius Ptolemy, who was bona at Pelle:him in Egypt, in the first century of the Christian era, is well known as the thor of a great work on asuunemy, entitled his Almagen, which contains a complete spa ' tem of astronomy drawn from 'heel-serration of all preceding astronomers in union with his own. He maintained the generally received opinion of the sun's motion, which combined to be universally held until the time of Coper . Mots. The work of Ptolemy being preserr ed front the ' conflagration that coo . sumecl the ion library during the • ravages of the Saracens, was translated out of r the Creel; into the Arabic, a- a 827 ; and, by the help of this translation, the Arabian; who : now addicted themselves to the study of as tronomy, cultivated it with great advantage under the patronage of the caliphs, particular ly Al Manion, who was himself an astronomer, and made many accurate vans ate the help of instruments, which he himself con structed. He determined the obliquity of the ecliptic in his time to be 23 degrees 35 min utes. Among the Arabian authors of this period was Alfragan, who wrote his Elements of Astronomy, and Albeanius, who flourish ed about SSO. This latter compared his own observations with those of Ptolemy, and com puted the motion of the san's apogee from Ptolemy's time to his own. He also compos. ed tables for the meridian of Arabia, which were much esteemed by his countrymen. Af ter this, din Yeamis, astronomer to the ca liph of Egypt, observed some eclipses, by means of which the quantity of the moon's acceleration since that time has ben determin ed ; also Arzechel„ a moor of Spain, observed the obliquity of the ecliptic ; and Alhazen his contemporary, wrote on the twilight, the height of the clouds, and the phenomena of the horizontal moon. Ile likewise first an. ployed the optical science in astronomical ob serrations, and showed the importance of the theory of refraction in astronomy.