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46

eratosthenes;

stadium was employed* If we assume'the Olym­pic stadium (202£ yards), the degree of Eratos­thenes is more than 79 miles, upwards of 10 miles* too great. Nothing is known of any Egyptian stadium. Plirty (I. c.) asserts that Hipparchus, but for what reason he does not say, wanted to add 25,000 stadia to the circumference as found by Eratosthenes.

According to Plutarch (de Plac. Phil. ii. 31), Era­tosthenes made the sun to be 804 millions of stadia from the earth, and the moon 780,000; according to Macrobius (in Somn. Scip. i. 20), he made the diameter of the sun to be 27 times that of the earth. (Weidler, Hist. Astron.; Fabric. Bibl. Graec. vol. iv. p. 117, &c. ; Delambre, Hist, de VAstron.Anc.; Petavius, Uranologion.} [A.dem.]

With regard to the other merits of Eratosthenes, we must first of all mention what he did for geo­graphy, which was closely connected with his ma­thematical pursuits. It was Eratosthenes who raised geography to the rank of a science; for, pre­vious to his time, it seems to have consisted, more or less, of a mass of information scattered in books of travel, descriptions of particular countries, and the like. All these treasures were accessible to Eratosthenes in the libraries of Alexandria ; and he made the most profitable use of them, by collecting .the scattered materials, and uniting them into an organic system of geography in his comprehensive work entitled Fewypa^/ea, or as it is sometimes, but erroneously, called, yewypa^o^eva or yewypct-<j>la. (Strab. i. p. 29, ii. p. 67, xv.p. 688; Schol. ad Apollon. Rhod. iv. 259, 284, 310.) It consisted of three books, the first of which, forming a sort of introduction, contained a critical review of the la­bours of his predecessors from the earliest to his own times, and investigations concerning the form and nature of the earth, which, according to him, was an immovable globe, on the surface of which traces of a series of great revolutions were still visible. He conceived that in one of these revolu­tions the Mediterranean had acquired its present form; for, according to him, it was at one time .a large lake covering portions of the adjacent coun­tries of Asia and Libya, until a passage was forced open by which it entered into communication with the ocean in the west. The second book contained what is now called mathematical geography. His attempt to measure the magnitude of the earth has been spoken of above. The third book contained the political geography, and gave descriptions of the various countries, derived from the \$orks of earlier travellers and geographers. In order to be able to determine the accurate site of each place, he drew a line parallel with the equator, running from the! pillars of Heracles to the extreme east of Asia, and dividing the whole of the inhabited earth into two halves. Connected with this work was a new map of the earth, in which towns, mountains, rivers, lakes, and climates were marked according to his own improved measurements. This impor­tant work of Eratosthenes forms an epoch in the history of ancient geography; but unfortunately it is lost, and all that has survived consists in frag-

* This is not so much as the error of FernePs measure, which so many historians, by assuming him, contrary to his own statement, to have used the Parisian foot, have supposed to have been, ac­cidentally, very correct. See the Penny Cyclo­paedia, Art. "Weights and .Measures/'

ERATOSTHENES

{ ments quoted by later geographers and historians, such as Polybius, Strabo, Marcianus, Pliny, and others, who often judge of him unfavourably, and controvert his statements; while it can be proved that, in a great many passages, they adopt his opi­nions without mentioning his name. Marcianus charges Eratosthenes With having copied the sub­stance of the work of Timosthenes on Ports (ir€pl AifjLsvcov), to which he added but very little of his own. This charge may be well-founded, but can­not have diminished the value of the work of Era­tosthenes, in which that of Timosthenes can have formed only a very small portion. It seems to have been the very overwhelming importance of the geography of Eratosthenes that called forth a number of opponents, among whom we meet with the names of Polemon, Hipparclms, Polybius, Serapion, and Marcjanus of Heracleia. The fragr ments of this work were first collected by L. Ancher, Diatribe in Fragm. GeograpTi. Eratosth.) Gbttingen, 1770, 4to., and afterwards by G. C. F. Seidel, Eratostli. Geograph. Fragm. Gb'ttingen, 1789, 8vo. The best collection is that of Bernhardy in his Eratosfkenica.

Another work of a somewhat similar nature, en­titled 'Ep/jrfs (perhaps the same as theKaTaorepKr/W mentioned above), was written in verse and treated of the form of the earth, its temperature, the diffe­rent zones, the constellations, and the like. (Bern-hardy, Eratosth. p. 110, &c.) Another poenij 'Hpi7oj/>7, is mentioned with great commendation by Longinus. (De Sullim. 33. 5 ; comp. Schol. ad Horn. 11. x. 29; Bernhardy, I.e. p. 150^ &c.) ;

Eratosthenes distinguished himself also as a phi-* losopher, historian, and grammarian. His acquire­ments as a philosopher are attested by the works which are attributed to him, though we may not believe that all the philosophical works which bore his name were really his productions. It is, how­ever, certain that he wrote on subjects of moral philosophy, e. g. a work Tlepl 'AyaOoav Kal ko.kuv (Harpocrat. s. v. dpftocrrat; Clem. Alex. Slrom. iv. p. 496), another ilepl TI\ovrov Kal Tlevias (Diog. Laert. ix. 66 ; Plut. Tliemist. 27), which some be­lieve to have been only a portion of the preceding work, just as a third TIspl 'AAvrr/ay, which is men­tioned by Suidas. Some other works, on the other hand, such as Tlepl t&v tcard «£(Aocro<p£az/ Afpecrewy, MeAera/, and Aid\oyoi9 are believed to have been erroneously attributed to him. Athenaeus men­tions a work of Eratosthenes entitled 'Aptnwfy (vii. p. 276), Epistles (x. p. 418), one Epistle ad­dressed to the Lacedaemonian Agetor (xi. p. 482)^ and lastly, a work called 'Ap/trrwr, after his teacher in philosophy, (vii. p. 281.)

His historical productions are closely connected with his mathematical pursuits. He is said to have written on the expedition of Alexander the Great (Plut. Alex. 3, 31, &c.; Arrian, Andb. v. 5. § 3) ; but the statements quoted from it belonged in all probability to his geographical or chronolo­gical work. Another on the history of the Gala-tians (raAari/ca), of which the 33rd book is quoted by Stephanus of Byzantium (s. v. c/Y5p?]Aa), was undoubtedly the work of another Eratosthenes. (Schmidt, de Gall. Exped. p. 15, &c.; Bernhardy, /. c. p. 243, &c.) There was, however, a very im­portant chronological work, entitled Xpovoypatyia, or XpovoypaQiw, which was unquestionably the production of our Eratosthenes. In it the author endeavoured to fix the dates of all the important