HERON'S INEXHAUSTIBLE GOBLET

Moshe F Rubinstein, Patterns of Problem Solving, Prentice-Hall, 1975

Heron (also known as Hero), who lived in Alexandria in the first century A.D. was one of the early contributors to feedback control. In one of his creations, a float valve was employed to maintain a constant level of wine in an "Inexhaustible Goblet," as shown [at right].