Images(4)

hydrometer with thermometer

Datecirca 1850

Inventory NumberDW0792

ClassificationHydrometer

Subject

Maker R. G. Greiner

Owner Schlagintweit Brothers 1854 - 1858

Cultural Region

Place of Origin

Dimensions29 x 3 x 3 cm (11 7/16 x 1 3/16 x 1 3/16 in.)
case: 40.6 x 9 x 9 cm (16 x 3 9/16 x 3 9/16 in.)

Material

Accessoriesblack cylindrical cardboard case

DescriptionA hydrometer consisting of a glass tube with a spherical air-filled chamber connected by a long neck to a pair of bulbs at its bottom, one filled with mercury that also acts as a thermometer's reservoir, and a second larger bulb underneath also partially filled with mercury. On its other end the air-filled bulb is connected to a long stem that contains a paper scale wrapped inside. A thin glass tube inside the hydrometer extends from the mercury reservoir to the stem above where it is marked with a thermometer scale.

The instrument has two scales, one for the hydrometer going from 1000 to 0.650 degrees Baumé, and one for the thermometer going from 8 to 30 degrees Réaumur. Additional density scale: 0 to -90 Beck.

Signedmarked on scale: R.G. Greiner München

Curatorial RemarksStored with DW0790, DW0791 and DW0793.

FunctionThis is an instrument that functions as a hydrometer for liquids lighter than or equal in density to water, and also as a thermometer. One lets the hydrometer float on the liquid and then one takes a density reading at the height indicated by the liquid's surface. The mercury bulb will be submerged during its use so the thermometer indicates the liquid's temperature as well.

ProvenanceAcquired with other instruments from the Schlaginweit Expedition in Germany, 1959 (Object 35). Donated to CHSI August 17, 1988.

Historical AttributesThis instrument appears to have been to the Schlaginweit Expedition to Central Asia between 1854 and 1858.