Six's thermometer

A maximum–minimum thermometer. The scales are Fahrenheit on the inside of the U and Celsius on the outside. The current temperature is 23 degrees Celsius, the maximum recorded is 25, and the minimum is 15; both read from the base of the small markers in each arm of the U tube. The bulbs are hidden by a plastic housing.

Six's maximum and minimum thermometer is a registering thermometer that can record the maximum and minimum temperatures reached over a period of time, for example 24 hours. It is used to record the extremes of temperature at a location, for instance in meteorology and horticulture. It was invented by the British scientist James Six, in 1780;[1] the same basic design remains in use.

It is also commonly known as a maximum–minimum, minimum–maximum, maxima–minima or minima–maxima thermometer, of which it is the earliest practical design.

The thermometer indicates the current temperature, and the highest and lowest temperatures since the last reset.

  1. ^ Synonyms Monthly Meteorological Magazine. H.M. Stationery Office. 1869.