A thermometer that automatically registers the lowest temperature attained during an interval of time. The alcohol-in-glass minimum thermometer contains a dumbbell-shaped index that is kept on the bulb side of the meniscus by surface tension. The thermometer is installed in a horizontal mounting (see Townsend support) so that as the temperature falls, the index is pulled toward the bulb and remains at the minimum point as the temperature rises. A bimetallic thermometer with a circular dial is also used as a minimum thermometer. A free index, mounted concentrically with and driven by the thermometer index, is held by friction at the minimum temperature. Compare maximum thermometer.