Harry Thurston Peck, Harpers Dictionary of Classical Antiquities (1898) alphabetic letter D Pursuing the steps of his brother, who amplified the theory of conic sections, Dinostratus is said to have made many mathematical discoveries; but he is particularly distinguished as the inventor of the quadratrix, though there is some reason for ascribing the original invention of this curve to Hippias of Elea (Proclus, Comment. in Eucl. (19.67)