Thermometer dividing engine, London, England, 1925-1940
Scales upon thermometers were accurately marked using this dividing engine. Thermometers must be made to a very high quality to be accurate. The glass needs to be carefully blown so the tube width is the same along its whole length. The dividing engine then has to make precise and consistent scales on the outside of the thermometer. It was made by F. W. Johnson and Daughter of Hendon, north London.
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Measurement is the process of estimating the magnitude of some attribute of an object, such as its length or weight, relative to some standard (unit of measurement), such as a meter or a kilogram. The act of measuring usually involves using a measuring instrument, such as a ruler, weighing scale, thermometer or speedometer which is calibrated to compare the measured attribute to a measurement unit. Metrology is the scientific study of measurement.
Glossary: dividing engine
Glossary: linear dividing engine
A machine for accurately dividing the linear scales of various measuring instruments, such as thermometers, and for producing glass graticules.