Note 22 — Chapter VI · PLATONIC CANON, AS RECOGNISED BY THRASYLLUS.
Reading edition
About the number of books, or more properly of rolls (volumina), in the Alexandrine library, see the enquiries of Parthey, Das Alexandrinische Museum, p. 76-84. Various statements are made by ancient authors, some of them with very large numbers; and no certainty is attainable. Many rolls would go to form one book. Parthey considers the statement made by Epiphanius not improbable — 54,800 rolls in the library under Ptolemy Philadelphus (p. 83).
The magnitude of the library at Alexandria in the time of Eratosthenes, and the multitude of writings which he consulted in his valuable geographical works, was admitted by his opponent Hipparchus (Strabo, ii. 69).