In Minimum thermometer, material used is

In the minimum thermometer, the material used is Alcohol.
The minimum thermometer is one that automatically registers the lowest temperature attained during an interval of time. The alcohol in the 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 so that as the temperature falls, the index is pulled toward the bulb and remains at the minimum point as the temperature rises.