a geometrician, famous on account of the invention of the curve called conchoid, which is equally useful in resolving the two problems of doubling the cube and trisecting the angle. It appears that he lived soon after Eratosthenes, for he rallied that philosopher on the mechanism of his mesolabe. Geminas, who lived in the second century before Jesus Christ, has written on the conchoid, though Nicomedes was always esteemed the inventor of it. Those who place him four or five centuries after Jesus Christ must be ignorant of these facts, by which we are enabled to ascertain pretty nearly the time in which he lived.