He also wrote Lives of Poets. We hear of books on Alcaeus and on Homer, in which latter he is said to have made the startling remark that the poems 'should be pronounced in the Aeolic dialect'. Whatever this remark exactly meant, and we cannot tell without the context, it seems an extraordinary anticipation of modern philological discoveries. He wrote on the Hypotheses—i. e. the subject matter—of Sophocles and Euripides; also on Musical Contests, περὶ Μουσικῶν ἀγώνων, carrying further Aristotle's own collection of the Didascaliae, or official notices of the production of Tragedies in Athens. The book dealt both with dates and with customs; it told how Skolia were sung, with a laurel or myrtle twig in the hand, how Sophocles introduced a third actor, and the like.
In philosophy proper he wrote On the Soul, περὶ ψυχῆς. His first book, the Corinthiacus, proved that the Soul was a 'harmony' or 'right blending' of the four elements, and was identical with the force of the living body. The second, the Lesbiacus, drew the conclusion that, if a compound, it was destructible. (Hence a great controversy with his master.)
He wrote περὶ φθορᾶς ἀνθρώπων, on the Perishing of Mankind; i. e. on the way in which large masses of men have perished off the earth, through famine, pestilence, wild beasts, war, and the like. He decides that man's most destructive enemy is Man. (The subject may have been suggested to him by a fine imaginative passage in Aristotle's Meteorology (i. 14, 7) dealing with the vast changes that have taken place on the earth's surface and the unrecorded perishings of races and communities.)
He wrote a treatise against Divination, and a (satirical?) Descent to the Cave of Trophonius. He seems, however, to have allowed some importance to dreams and to the phenomena of 'possession'.
And, with all this, we have not touched on his greatest work, which was in the sphere of geography. He wrote a Περίοδος γῆς, a Journey Round the Earth, accompanied with a map. He used for this map the greatly increased stores of knowledge gained by the Macedonian expeditions over all Asia as far as the Ganges. He also seems to have devised the method of denoting the position of a place by means of two co-ordinates, the method soon after developed by Eratosthenes into Latitude and Longitude. He attempted calculations of the measurements of large geographic distances, for which of course both his data and his instruments were inadequate. Nevertheless his measurements remained a well-known standard; we find them quoted and criticized by Strabo and Polybius. And, lastly, he published Measurements of the Heights of Mountains in the Peloponnese; but the title seems to have been unduly modest, for we find in the fragments statements about mountains far outside that area; about Pelion and Olympus in Thessaly and of Atabyrion in Rhodes. He had a subvention, Pliny tells us (N. H. ii. 162, 'regum cura permensus montes'), from the king of Macedon, probably either Cassander or, as one would like to believe, the philosophic Antigonus Gonatas. And he calculated the heights, so we are told, by trigonometry, using the δίοπτρα, an instrument of hollow reeds without lenses which served for his primitive theodolite. It is an extraordinary record, and illustrates the true Peripatetic spirit.
FOOTNOTES:
[79:1] Hellen. ii. 2, 3.
[80:1] Cf. Tarn, Antigonus Gonatas, p. 52, and authorities there quoted.
[81:1] Lysias, xxxiii.