Editing Library of Alexandria (section)

===Later scholarship and expansion===
The third head librarian, [[Eratosthenes of Cyrene]] (lived {{circa}} 280–{{circa}} 194 BC), is best known today for his scientific works, but he was also a literary scholar.{{sfn|Staikos|2000|page=66}}{{sfn|Montana|2015|page=114}}{{sfn|MacLeod|2000|page=6}} Eratosthenes' most important work was his treatise ''Geographika'', which was originally in three volumes.{{sfn|Montana|2015|page=115}} The work itself has not survived, but many fragments of it are preserved through quotation in the writings of the later geographer [[Strabo]].{{sfn|Montana|2015|page=115}} Eratosthenes was the first scholar to apply mathematics to geography and map-making{{sfn|Montana|2015|page=116}} and, in his treatise ''Concerning the Measurement of the Earth'', he calculated the circumference of the earth and was only off by less than a few hundred kilometers.{{sfn|Montana|2015|page=116}}{{sfn|MacLeod|2000|page=6}}{{sfn|Casson|2001|page=41}} Eratosthenes also produced a map of the entire known world, which incorporated information taken from sources held in the Library, including accounts of [[Indian campaign of Alexander the Great|Alexander the Great's campaigns in India]] and reports written by members of Ptolemaic elephant-hunting expeditions along the coast of [[East Africa]].{{sfn|Casson|2001|page=41}}

Eratosthenes was the first person to advance geography towards becoming a scientific discipline.{{sfn|Montana|2015|pages=116–117}} Eratosthenes believed that the setting of the Homeric poems was purely imaginary and argued that the purpose of poetry was "to capture the soul", rather than to give a historically accurate account of actual events.{{sfn|Montana|2015|page=115}} Strabo quotes him as having sarcastically commented, "a man might find the places of Odysseus' wanderings if the day were to come when he would find the leatherworker who stitched the goatskin of the winds."{{sfn|Montana|2015|page=115}} Meanwhile, scholars at the Library of Alexandria displayed interest in other scientific subjects.{{sfn|Montana|2015|page=117}}{{sfn|MacLeod|2000|pages=6–7}} [[Bacchius of Tanagra]], a contemporary of Eratosthenes, edited and commented on the medical writings of the [[Hippocratic Corpus]].{{sfn|Montana|2015|page=117}} The doctors [[Herophilos|Herophilus]] (lived {{circa}} 335–{{circa}} 280 BC) and [[Erasistratus]] ({{circa}} 304–{{circa}} 250 BC) studied [[human anatomy]], but their studies were hindered by protests against the [[dissection]] of human corpses, which was seen as immoral.{{sfn|MacLeod|2000|page=7}}

According to Galen, around this time, Ptolemy III requested permission from the Athenians to borrow the original manuscripts of [[Aeschylus]], [[Sophocles]], and [[Euripides]], for which the Athenians demanded the enormous amount of fifteen [[Talent (measurement)|talents]] ({{convert|1000|lbs|kg|abbr=on|disp=semicolon}}) of a precious metal as guarantee that he would return them.<ref name="Galenxviia">[[Galen]], xvii.a, [http://www.attalus.org/translate/extracts.html#17a.605 p. 607]</ref>{{sfn|MacLeod|2000|page=4}}{{sfn|Casson|2001|page=35}}{{sfn|McKeown|2013|pages=147–148}} Ptolemy III had expensive copies of the plays made on the highest quality papyrus and sent the Athenians the copies, keeping the original manuscripts for the library {{sfn|Phillips|2010}} and telling the Athenians they could keep the talents.<ref name="Galenxviia"/>{{sfn|MacLeod|2000|page=4}}{{sfn|Casson|2001|page=35}}{{sfn|McKeown|2013|pages=147–148}} This story may also be construed erroneously to show the power of Alexandria over Athens during the [[Ptolemaic dynasty]]. This detail arises from the fact that Alexandria was a man-made bidirectional port between the mainland and the [[Lighthouse of Alexandria|Pharos]] island, welcoming trade from the East and West, and soon found itself to be an international hub for trade, the leading producer of papyrus and, soon enough, books.{{sfn|Trumble|MacIntyre Marshall|2003}} As the Library expanded, it ran out of space to house the scrolls in its collection, so, during the reign of Ptolemy III Euergetes, it opened a satellite collection in the [[Serapeum of Alexandria]], a temple to the Greco-Egyptian god [[Serapis]] located near the royal palace.{{sfn|MacLeod|2000|page=5}}{{sfn|Casson|2001|page=34}}{{sfn|Haughton|2011}}