Liquid thermometers

Introduction
Thermometers using thermal expansion of liquid' (mercury). The capillary (the air is exhausted from it) expands at the lower end into a cylindrical container filled with mercury.

Mercury thermometers can be used to measure temperatures from −39 to +250 °C. For lower temperatures, thermometers filled with colored "toluene or ethyl alcohol" are used.

Medical Thermometer
It is used to measure body temperature (range 35-42 °C), the mercury level here remains at the highest measured value and must be cellared after use.