The treatise in question is ascribed by Goethe to Theophrastus, but it is included in most editions of Aristotle, and even attributed to him in those which contain the works of both philosophers; for instance, in the Aldine Princeps edition, 1496. Calcagnini says, the treatise is made up of two separate works on the subject, both by Aristotle.
His authority seems to have been equally great on subjects connected with the phenomena of vision; the Italian translator of a Latin treatise, by Portius, on the structure and colours of the eye, thus opens his dedication to the Cardinal Ercole Gonzaga, of Mantua:—"Grande anzi quasi infinito è l'obligo che ha il mondo con quel più divino che umano spirito di Aristotile."
In a letter to Ziegler the mathematician, Calcagnini speaks of Raphael as "the first of painters in the theory as well as in the practice of his art." This expression may, however, have had reference to a remarkable circumstance mentioned in the same letter, namely, that Raphael entertained the learned Fabius of Ravenna as a constant guest, and employed him to translate Vitruvius into Italian. This MS. translation, with marginal notes, written by Raphael, is now in the library at Munich. "Passavant, Rafael von Urbino."