CLEOME'DES, a Greek writer on astronomy. There is some doubt about the age in which he lived ; which is the same thing, whether the manuscripts remaining which bear tho name of Cleomcdes wero all written by one man, or two men at different times. The manu scripts which remain are on astronomy, on the doctrine of the sphere, and on arithmetic. Vossius conjectures that the work on music attributed to Cleonidas belongs to Cleomedes. Riccioli seems to have been one of the first who supposed that there were two of this name, one about the time of Augustus, the other in the reign of Theodosius. The work on astronomy was attributed by Vossius to the latter ; but the principal arguments against so late an anthor lie in his frequent mention of Pythagoras, Eratosthenes, Hipparchus, and Poaidonius, and his entire silence about Ptolemnus. See however the arguments of Letronne, Journal des Sevens,' 1821, p. 713.
We mean by Cleomedea the one of that name who wrote the work nap' KincAucis °caviar pErEctpcur, in two books, On the Circular Theory of the Heavenly Bodies.' It is professedly in several parts taken from a writing, or from the public lectures, of Posideniva, who was certainly the contemporary of Cicero. It is a probable conjecture that Cleo medes was a pupil of Posidonius. The work in question has considerable historical value; it records the measures of the earth by Posidoniva and Eratosthenes, establishes the antiquity of the opinion that the rotation of the moon is equal to her synodical revolution round the earth ;—had it been the sidereal revolution, it would have been correct. It gives various arguments in proof of the rotundity of the
earth, in opposition to the supposition of flat and cubical forms, ite., and from this source the early English writers drew much of what they said on the same subject. It mentions eclipses as having hap pened without having been predicted in the canons; a proof that something answering to an almanac was in common use. It decidedly suggests the possibility of rays of light being bent by the air. Delambre has made it sufficiently apparent that Cleomedes was not acquainted with the writings of Hipparchus, though he freqnently cites opinions and methods which he attributes to him.
The earlier editions of Cleomedes are :-1. The Latin version of George Valle, Venice, 1497 or 1498. 2. In Latin, with Aristotle and Philo, Basal, 1533. 3. The first Greek edition, by Conrad Neobarius, Paris, 1539. 4. In Greek and Latin with Aratus, Proclus, and Diony sius, Basel, 1547 ; again in 1561 ; again in 1585. 5. In Greek and Latin, with a Commentary, by George Balfour, Bordeaux, 4to, 1605. This edition was re-published with additional notes, by Janus Bake, Leipzig, 1820; this also was re-published, with additional notes, by C. C. Theoph. Schmidt, Leipzig, 1831. The most esteemed manuscript is that in the public library at Wittenberg.
(lliccieli, Vossius, Weidler, Heilbronner, Delambre, Hist. .4 gr. Ans. L 218.)