Jan P.Hogendijk

This article is devoted to two theorems on tangent circles, which were discovered by the Iranian geometer Abu Sah?l Kuhi (fourth century H.). The two theorems were inspired by the Book of Lemmas (makhudhat) attributed to Archimedes. Kuh?'s original treatise is lost, but the two theorems are found in Nas??r al-D? nTu?s?'s edition of the Lemmas of Archimedes. They then appeared in Latin translations in 1659 in London and again in 1661 in Florence, and in 1695 in a revised Dutch version in Amsterdam. The present article compares the original Arabic version of Kuh?'s theorems (in the presentation of T?us?) with the revised Dutch version.