A manuscript of Euclid's \textit{De Speculis}: A Latin text of MS 98. 22 of the Archivo y Biblioteca Capitulares de la Catedral, Toledo (Q2741020)

In 1992, Takahashi published a critical edition of three Medieval Latin versions of Euclid's (or ps-Euclid's) Catoptrica based on 24 manuscripts -- the very literal twelfth-century translation and two paraphrases. The present article contains an edition of a third paraphrase contained in a manuscript from the thirteenth or fourteenth century together with an English translation. A six-page introduction discusses the characteristics of this particular version, which is seen to agree well with what Takahashi following John Murdoch characterizes as the ``didactic concern'' of the epoch. The edition and the translation are not annotated.NEWLINENEWLINENEWLINEThe edition appears to be made with care. The translation contains a few flaws: for instance, the statement of prop. VI should run ``In plane mirrors, every object of sight is seen along a perpendicular drawn from the object'', not ``\dots{} from an object''; in prop. IX, ``manifestum est intellecti'' should be translated ``manifest to the intellect'' (or ``\dots{} to the faculty of understanding''), not ``manifest to an intelligent person''); similarly, in prop. 18 ``intelligenti'' should be ``the one who understand'' or ``the one with insight'', not ``an intelligent person''. In general, however, and in particular for everything that concerns the scientific subject-matter and not the rhetorical dress, the translation is adequate, and it is everywhere very readable. NEWLINENEWLINENEWLINEBeyond what is observed by Takahashi in the introduction it is worth noticing that the writer of the text claims in the end of the last proposition (on kindling fire with a spherically concave mirror) to have performed experiments on burning mirrors; reference to the use of a particular kind of stone suggest that these were alchemical in nature, which may explain that he also got an effect with convex mirrors; the proof itself, problematic in the original text, is ``improved'' into nonsense by means of premisses borrowed from natural philosophy (definitely non-Aristotelian, and identifying rays of light with fire).