Signedmarked on back: F.O. Robert Bötze Leipzig
Inscribedon back: Beckmann'sches Thermometer 1/100° Celsius [and] Normalglas
FunctionThis is a thermometer that the user can fill with different amounts of mercury to use at different temperature ranges. It is very precise but because of this it has a narrow range of 5.4 degrees Celsius. To set it up for use, the thermometer would be placed in contact with a substance a few degrees above the upper required limit of temperature, and enough mercury would then be poured in so that the stem filled up to the s-bend. That way, the thermometer would have a range up to that temperature.