[TRACTATO DELI CREPUSCOLI E DELE ASCENSIONI DELE NUVOLE]

Abstracttitle SUMMARY /title This short treatise by the eleventh century Spanish Muslim, Ibn Mu'dh, presents a unique method for determining the altitude of the atmosphere. The Arabic original is not extant, but the text survives in three medieval versions. Two of them were translated directly from the Arabic: a Latin version possibly by Gerard of Cremona in the late twelfth century, and a Hebrew version by Samuel ben Judah of Marseilles in the fourteenth century. The third is an anonymous Italian version, translated from Latin, preserved uniquely in a fourteenth century manuscript. The Hebrew and Italian versions are edited here.