ANAEROID BAROMETER SIX`S MAXIMUM AND MINIMUM THERMOMETER
SIX`S MAXIMUM AND MINIMUM THERMOMETER MERCURY BAROMETER
ANEMOMETER RAIN GAUGE
Six's thermometer is a thermometer which can measure the maximum and minimum temperatures reached over a period of time, usually during a day. It is commonly used wherever a simple way is needed to measure the extremes of temperature at a location, for instance in meteorology and horticulture.
It is also commonly known as a maximum minimum thermometer, of which it is the earliest practical design and the most common type used.
It gives three readings: the current temperature, the highest temperature reached since it was last reset, and the lowest temperature reached since it was last reset.
It was invented by Englishman James Six in 1782, and named after him. The same basic design remains in use today.
This describes the traditional construction. Modern designs may substitute materials for less toxic ones but operate in the same way.
It consists of a U-shaped glass tube with two separate temperature scales set along each arm of the U. One of these is for recording the maximum temperature encountered and the other for the minimum temperature. The arms of the U-shaped tube terminate in sealed glass bulbs. The bulb at the top of the minimum reading scale arm is full of alcohol, the other contains a vacuum (or low pressure alcohol vapour).
In the bend of the U is a section of mercury, a metal which is liquid at normal temperatures. This is pushed around the tube by...