This composite manuscript from the Basel Dominican Convent, one of several from the estate of Johannes Tagstern, was rebound in 1952 and contains texts on optics and geometry, such as the Dietrich of Freiburg's treatise on rainbows, with several clear, compass-and-ruler-drawn schemata. The first part was written on parchment in the fourteenth century, while the other, newer parts can be dated more precisely on the basis of the watermarks of the paper used to the end of the fourteenth century or to the beginning of the fifteenth century, that is, to the period in which the previous owner, Tagstern, is attested on the last page (f. 157v) as a member of the Dominican Convent. (mag)