naṣīr al-dīn al-ṭūsī’s version of the measurement of the circle of archimedes from his revision of the middle books

the mathematical treatises known as ta?r?r al-mutawassi??t, “revision of the middle books”, are a collection of greek and arabic treatises which were re-edited by na??r al-d?n al-??s?. this paper explores the nature of the editorial work ??s? did, showing that it is not a simple rendering of the original text but that it involves major revisions and in fact original additions. for the first time, a collated version of ??s?’s revision on the treatise on the measurement of the circle (by archimedes) is provided. a translation of the arabic text is put side by side with a rendition of the treatise as it was circulated before ??s?’s time. an in-depth analysis of the text elucidates the nature of ??s?’s contributions to the text. this article also provides modest corrections to earlier studies by w. r. knorr and p. luckey.