Figure 14. Negretti and Zambra thermometers, older models. These were
reversing thermometers completely protected by an outer glass casing. This type
of thermometer was manufactured from 1878 until 1912. The scales were graduate
d in degrees and half-degree centigrade. Length of these thermometers was about
24 cm, diameter of reservoir about 1.1 cm, and diameter of tube about 1.3 cm.