Measurement and Control: items 43, 46, 71, 90, 77, 81
The measurement of temperature by thermometer readings was an essential monitoring technique for both investigative and preparative work. Items 43, 71 and 90 show typical standard thermometers and thermometers with protective housings for special applications.
A long forgotten technique for the estimation of oxygen in air and other gas mixtures is Eudiometry, widely practiced in the 18th century. The technique effectively measured the decrease in volume of a gas with the reaction and removal of the reactive component, by means of the graduated tubes shown, item 77. See Cavendish, “An account of a new Eudiometer”, Phil Trans. Roy. Soc. Lond. 73 (1783) 106.
The hydrometer (Item 46) measured the density of a liquid and was particularly important in the operations of the excise acts on the production and sale of alcoholic spirits. It was the subject of extensive investigation and development during the 18th century, important historical figures such as Baume, Lavoisier, Homburg and Fahrenheit being involved. The expression “proof” in relation to the strength of spirits is related to the standard density of 50% alcohol in water at 60 degrees F, which is given the designation “100% proof”
The saccharimeter (item 81) is a variation on the hydrometer principle, applied to the strength of sugars in solution, and much used by Brewers.