Written by the 11th-century Spanish Arab, Abh Muhammad ibn MucnOn Twilight and the Rising of Cloudsdh's value of around 52 miles remained standard until the 17th century, when it was revised sharply downward in consideration of atmospheric refraction and barometric studies. The treatise itself survives in a single Hebrew exemplar, 25 Latin exemplars, and an Italian exemplar derived from the Latin. At the heart of this present study is a critical text based on a fullscale comparative transcription of 22 of (...) the Latin manuscripts, ranging in date from the 13th to the 17th century. (shrink)