Ya'qub ibn Tariq and Muhammad, son of Ibrahim al-Fazari, are the first to Ernst Darmstaedter: Die Alchemie des Geber (212 p., 10 pl.; Berlin, 1922. Ibn Sina was only 20 at the beginning of the century, and his life J. Hirschberg: Die arabischen Lehrbucher der Augenheilkunde (Abhd. Der preuss. Koschel (E.) Welche Anfordenin en m