HERO, the name of two celebrated Greek mathema-
Herod. ticians; the one called the older and the other the younger Hero. The latter was a disciple of Ctesibius. They are known by two works translated into Latin by Barochius; Spiralium liber, by Hero the elder; and Tractat. Artis et Machin. Militar. by Hero the younger. They flourished about 130 and 100 B. C.