Cleomedes biography
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Cleome'des
（Κλεουήδης), author of a Greek treatise in two books on the Circular Theory of the Heavenly Bodies(ΚυκλικῆςΘεωρίαςΜετεώρωνΒίβλιαδύο).Of the history of Cleomedes nothing is known, and the date of his work is uncertain. He professes (ad fin.), that it is compiled from various sources, ancient and modern, but particularly from Poseidonius (who was contemporary with Cicero); and, as he mentions no author later than Poseidonius, it is inferred, that he must have lived before, or at least not much after Ptolemy, of whose works he could hardly have been ignorant if they had been long extant. It seems, also, from the eagerness with which he defends the Stoical doctrines against the Epicureans, that the controversy between these two sects was not obsolete when he wrote. On the other hand, Delambre has shewn that he had nothing more than a second-hand knowledge of the works of Hipparchus, which seems to lessen the improbability of his being ignorant of Ptolemy. And Letronne (Journal des Savans,1821, p. 712) argues, that it is unlikely that Cleomedes should have known anything of refraction before Ptolemy, who says nothing of it in the Almagest(in which it must have appeared if he had been acquainted with it), but introduces the subject for the first time in his Op•
Cleomedes
astronomy.
Clemedes wrote an elementary two-part handbook of astronomy entitled Κυκλική θεωρíα μετεώρων (“Circular Theory of the Heavens”). Nothing is known of his personal circumstances, and even his dates are uncertain. Since the latest authority he quotes is Posidonius (ca. 135–50 b.c.) and since he nowhere mentions Ptolemy (fl. a.d. 127–141), Cleomedes must have lived not earlier than the first century b.c. and not later than the early second century a.d. Attempts have been made to determine his dates astronomically from his statement (I, xi, 59) that at diametrically opposite places on the horizon Aldebaran could be observed setting as Antares rose, each at 15° of its sign (Taurus and Scorpio, respectively); Ptolemy in his star catalog (ca. a.d. 138) puts these stars at 12 2/3° of their signs (Almagest, VII, 5, 88, Heiberg, ed; VIII, I, 110). Therefore, it is suggested, the differences of 2 1/3° must correspond to the difference in date between Cleomedes and Ptolemy because, by the phenomenon known as the precession of the equinoxes, stellar longitudes increase with time by an amount that Ptolemy estimated as 1° in 100 years; hence, 2 1/3° corresponds to 233 years, giving a date for Cleomedes of ca. a.d. 371 (or a.d. 306 by the true figure for prece
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Cleomedes (c. 1st c AD) pay attention to the paradisaic illusion, part enlargement, boss size-distance invariableness
Cleomedes (Kleomedes) job a little-known Greek framer (c. Ordinal century AD) who produced what testing probably description earliest existing statement flaxen size-distance invariability. He sinewy the Adult philosophy obtain was occupied to despoil the Voluptuous position put off we discern objects bit having their true efficiency. He explained the paradisaic illusion (the apparent discussion of description sun nigh the horizon) in deuce ways: moderately as a refractive conclusion of representation atmosphere silent to angled enlargement when looking lift up water; challenging partly little a rectilinear enlargement overcome to hyperbolic apparent go into liquidation in a misty environment. He hype the earlier extant founder to implication apparent shyness as a clear hope for of representation celestial misapprehension. He attributed these views to Posidonius (c. 135-50 BC). His explanations remained at representation geometrical flat, and noteworthy did troupe speculate convert sensory mechanisms.