Mercury-in-glass thermometer Mercury-in-glass thermometer The mercury-in-glass or mercury thermometer was invented by physicist Daniel Gabriel Fahrenheit in Amsterdam (1714). It consists of a bulb containing mercury attached to a glass tube of narrow diameter; the volume of mercury in the tube is much less than the volume in the bulb. The volume of mercury changes slightly with temperature; the small change in volume drives the narrow mercury column a relatively long way up the tube. The space above the mercury may be filled with nitrogen gas or it may be at less than atmospheric pressure, a partial vacuum. In order to calibrate
Reversing thermometer They are usually read to 0.01°C, and after the proper corrections have been applied, their readings are considered reliable to 0.02°C. Reversing thermometer Unlike most conventional mercury thermometers, a reversing thermometer is able to record a given temperature to be viewed at a later time. If the thermometer is flipped upside down, the current temperature will be shown until it is turned upright again. This was the primary device used by oceanographers to determine water temperatures below the surface of the ocean from around 1900 to 1970. It consists of a conventional bulb connected to a capillary in which a