world is of especial interest, both for his own views and for those he criticises.[334] Strabo lived about B.C. 60 to A.D. 24. The works of Marinus of Tyre having perished, the next important geographical work in Greek is the world-renowned _Geography_ of Ptolemaeus, who wrote in the second half of the second century A.D. Despite the peculiar merits and history of this work, it is not so important for our purpose as the work of Strabo, though it exercised infinitely more influence on the Middle Ages and on early modern geography.[335] The astronomical writers are also of importance. Eudoxus of Cnidus, said to have first adduced the change in the altitude of stars accompanying a change of latitude as proof of the sphericity of the earth, wrote works now known only in the poems of Aratus, who flourished in the latter half of the third century B.C.[336] Geminus (circ. B.C. 50),[337] and Cleomedes,[338] whose work is famous for having preserved the method by which Eratosthenes measured the circumference of the earth, were authors of brief popular compilations of astronomical science. Of vast importance in the history of learning was the astronomical work of Ptolemy, _ἡ μεγάλη σύνταξις τῆς ἀστρονομίας_, which was so honored by the Arabs that it is best known to us as the _Almagest_, from _Tabric al Magisthri_, the title of the Arabic translation which was made in 827. It has been edited and translated by Halma (Paris, 1813, 1816). Much is to be learned from the _Scholia_ attached in early times to the works of Hesiod, Homer, Pindar, the _Argonautica_ of Apollonius Rhodius (B.C. 276-193?), and to the works of Aristotle, Plato, etc. In some cases these are printed with the works commented upon; in other cases, the _Scholia_ have been printed separately. The commentary of Proclus (A.D. 412-485) upon the _Timaeus_ of Plato is of great importance in the Atlantis myth.[339] Much interest attaches to the dialogue entitled _On the face appearing in the orb of the moon_, which appears among the _Moralia_ of Plutarch. Really a contribution to the question of life after death, this work also throws light upon geographical and astronomical knowledge of its time. Among the Romans we find much the same succession of sources. The poets, Virgil, Horace, Ovid, Tibullus, Lucretius, Lucan, Seneca, touch on geographical or astronomical points and reflect the opinion of their day.[340]