On the Arabic Translations of Eutocius’ Commentary on Book II of Archimedes’ Sphere and Cylinder

In the 9th century, parts of Eutocius’ commentary on Book II of Archimedes’ Sphere and Cylinder were translated into Arabic. Most extant manuscripts of these trans- lations contain only fragments. However, one manuscript, Escorial, Árabe 960, contains the longest known Arabic text of Eutocius’ commentary, at 41 folios long. Comparison with the Greek text reveals that the Arabic text in Escorial 960 is composed of the translations of two disjoint parts of Eutocius’ commentary, on Sphere and Cylinder II.1 and II.4. A comparison of various mathematical terms used in the two parts, which I call Text A and Text B, shows that they differ systematically, and were therefore probably translated by different individuals, in different scholarly contexts.