Six's thermometer is a registering thermometer which can record the maximum and minimum temperatures reached over a period of time, for example 24 hours.
The thermometer indicates the current temperature and the highest and lowest temperatures since last reset.
Our thermometer consists of a U-shaped glass tube with two separate temperature scales set along each arm of the U. One for recording the maximum temperature and the other for the minimum temperature.
The range of the thermometer is -30° to +60°C x 1°C and -20° to +140°F x 2°F.
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 spirit.
In the bend of the U, is a section of mercury, which is the indicator liquid.
The movement of mercury in the U-bend as a result of the expansion and contraction of spirit in both the limbs, forces the respective steel indices to move up along the column.
Readings are taken at the lower end of the indices, whose position can be reset by a magnet supplied along with the thermometer.
The entire set up is mounted on a plastic base.