- Any chemical laboratory will have a variety of mercury thermometers for monitoring and controlling temperatures. I have selected a two high grade precision laboratory thermometers from the HSU Chemistry Department's collection because of their interest or special qualities: one was N.B.S. Certified, the other came in a wood case (and thus I suspect it is actually from the1940's or 1950'). The thermometers are listed below:
- The department purchased a 0 - 100 °C laboratory thermometer
from Fisher Scientific Company (serial number: 4A2693) with a
National Bureau of Standards certificate (front,
back) of accuracy
in 1961. There is a lightly engraved mark on the back: NBS 53,
it is otherwise undistinguished.
- A quality 0 - 100 °C laboratory thermometer from Braun-Knecht-Heiman
in a wooden case.
- Until precision (constant)-bore tubing became available around
1970, thermometrs had to be made individually. The early references
by Minor and Duff below describe thermometer making and calibration
prior to constant bore tubing. The modern standardization of
thermometers began in the 1880's with the constant-volume hydrogen
scale acepted as the standard over the liquid water range in
1887. In 1927 it was replaced by the International Scale using
a platinum resistance thermometer for common laboratory temperature
ranges. This scale was replaced, after a couple of revisions,
in 1990 by ITS-90, a series of four overlapping scales. The normal
range of laboratory tempreatures still being based on a platinum
- Some early descriptions of the thermometer, its calibration
and use, are provided below:
- Burnett, John in Bud, Robert and Deborah Jean Warner,
eds. Instruments of Science: An Historical Encyclopedia.
Garland Publishing, Inc. New York (1998) pp 615-8.
- Middleton, W. E. Knowles. A History of the Thermometer
and Its Uses In Meteorology. Johns Hopkins Press (1966)
- © R. Paselk
- Last modified 13 August 2010