pyrheliometer
Date: mid 19th-early 20th Century
Inventory Number: 1998-1-0809
Classification: Pyrheliometer
Subject:
Maker: Eugène Ducretet (1844 - 1915)
User: Blue Hill Meteorological Observatory (1885-present)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
largest component: 8.5 × 49.7 × 7 cm (3 3/8 × 19 9/16 × 2 3/4 in.)
case: 8.5 × 50.5 × 13.2 cm (3 3/8 × 19 7/8 × 5 3/16 in.)
Accessories: Includes a hinged, lined case, with latch closures, and a leather strap coiled and attatched to case.
Description:
A pyrheliometer, or instrument for measuring solar radiation on a surface, housed in an instrument case. This instrument, known as a "normal incidence pyrheliometer" was used at the Blue Hill Meterological Observatory in Milton, Massachusetts.
The base consists of a pair of metal disks, separated by spacers, supporting a dark polished metal column (on which "E Ducretet a Paris No 50" is engraved in script). The column is connected to a spherical element, and the whole supports a slender metal tube, with openings on two sides, topped by another metal disk.
The instrument is stored in a long, flat, leather-covered wooden box, hinged on one edge, with a pair of latches on the other. The inside of the box is lined with red fabric and has indentations designed to securely hold the instrument parts. In addition to the base described above, the case contains another style of base and a separate glass and mercury thermometer. The case is stamped, "HAUT" and "BAS."
The base consists of a pair of metal disks, separated by spacers, supporting a dark polished metal column (on which "E Ducretet a Paris No 50" is engraved in script). The column is connected to a spherical element, and the whole supports a slender metal tube, with openings on two sides, topped by another metal disk.
The instrument is stored in a long, flat, leather-covered wooden box, hinged on one edge, with a pair of latches on the other. The inside of the box is lined with red fabric and has indentations designed to securely hold the instrument parts. In addition to the base described above, the case contains another style of base and a separate glass and mercury thermometer. The case is stamped, "HAUT" and "BAS."
Signedengraved in script on base: E Ducretet / a Paris / No 50
Inscribedlabel in case: A / actin. / P[erased]aisse;
stamped on case: HAUT and BAS;
stamped on case: HAUT and BAS;
FunctionPyrheliometers measure the total radiation on a horizontal surface, allowing calculations on atmospheric dustiness, and approximations of atmospheric water vapor content.
Curatorial RemarksBlue Hill 68(27).
Fabric coming off of wooden case, fabric distressed and water stained.
Fabric coming off of wooden case, fabric distressed and water stained.
Published ReferencesThe Blue Hill Meteorological Observatory: The First 100 Years - 1885-1985, John H. Conover, American Meteorological Society, 1990, Appendix B, p.438, No. 68. Also see p. 163-165 for a general discussion of several pyrheliometers.