half-minute glass

1 definition found

half-minute glass - Collaborative International Dictionary of English v.0.48 :

  Hourglass \Hour"glass`\, n.
     An instrument for measuring time, especially the interval of
     an hour. It consists of a glass vessel having two
     compartments, from the uppermost of which a quantity of sand,
     water, or mercury occupies an hour in running through a small
     aperture unto the lower.
     [1913 Webster]
  
     Note: A similar instrument measuring any other interval of
           time takes its name from the interval measured; as, a
           half-hour glass, a half-minute glass. A
           three-minute glass is sometimes called an egg-glass,
           from being used to time the boiling of eggs.
           [1913 Webster]