Johannes Fontana als Verfasser der Speculi almukefi compositio und sein Exkurs über den Stahl (ca. 1430)

Abstract

The anonymously transmitted Speculi almukefi compositio is one of the most original works that the Middle Ages brought out on conic sections and construction of parabolic mirrors. The author is suspected to have been an unknown monk of the 13th/14th century. Based on source documents that were previously left unconsidered, this article assigns the tract to the Venetian Johannes Fontana. The diversely interested doctor of arts and medicine practiced as a physician in Udine in the 1430s, a time during which he wrote about geometric subjects. The close relationship to practical application is typical for the scientist Fontana. It is expressed in an excursion on the conditions of a good steel. The rich text, still to be evaluated from a technical-historical point of view, is published here in a German translation for the first time.