Description:
Maximum registering pocket thermometer, mercury filled. Total immersion thermometer made from white back glass. 160mm (6.3") length. Open aluminum case. Designed for maximum temperature measurement. Bore constriction permits the mercury column to rise and hold at maximum temperature. When removed from heat source, mercury will break at constriction and remain at that temperature until shaken down. These are also known as “bottom hole” thermometers used by oil well logging companies to measure temperatures in wells.