Paul Kollsman

Born: 1900

Altimeter. Prior to 1928, there was no reliable or accurate way for airplane pilots to know how far above the ground they were. The barometric altimeter, accurate within 20 feet, measured altitude by assessing barometric pressure and enabled pilots to fly “blind.”

Died: 1982

Willem J. KolffThe National Inventors Hall of FameWilliam J. Kroll