black bulb thermometer
Date1890-1910
Inventory Number1998-1-1250
ClassificationThermometer
Subject
Maker
Henry J. Green
fl. 1885 - 1910
User
Blue Hill Meteorological Observatory
1885-present
Cultural Region
Place of Origin
Place of Use
Dimensions46 x 6.5 x 6.5 cm (18 1/8 x 2 9/16 x 2 9/16 in.)
Material
DescriptionA thermometer consisting of a thin glass tube with a capillary that has a scale. Its mercury bulb is painted completely black and is in the shape of a sphere at the end of a cylindrical stem. The whole thermometer is kept inside a clear glass vessel with a large spherical bulb surrounding the thermometer's mercury bulb such that it is exactly at its center.
Signedon stem opposite scale: Henry J. Green N.Y. No.3680
FunctionThis is a thermometer for determining the amount of heat radiation (infrared light) in the environment at a certain moment. Its mercury bulb is isolated from contact with the ambient temperature by an evacuated glass vessel, and it is painted completely black so it will absorb the maximum possible heat radiation.
Heat radiation is an important meteorological reading as an indication of cloudiness and contributes to the subjective perception of ambient temperature in addition to the temperature of air.
Heat radiation is an important meteorological reading as an indication of cloudiness and contributes to the subjective perception of ambient temperature in addition to the temperature of air.
ProvenanceFrom the Blue Hill Meteorological Observatory.
Henry J. Green
Date: 1890-1910
Accessories: cardboard box
Object number: 1998-1-1271b
Henry J. Green
Date: 1890-1910
Accessories: cardboard box
Object number: 1998-1-1271a
Alvergniat Frères
Date: circa 1890
Accessories: inside an old wooden box with space for two thermometers of this kind, but with only this one present. Other contents and inscriptions of box described in Inscriptions.
Object number: 1998-1-0420