Campbell-Stokes burning glass sunshine duration recorder
Date: circa 1886
Inventory Number: 1998-1-0836a,b
Classification: Sunshine recorder
Subject:
Maker: L. Casella (1860 - 1905)
Maker: C. F. Casella & Co. Ltd. (founded 1905)
User: Blue Hill Meteorological Observatory (1885-present)
User: Institute of Geographical Exploration (1929 - 1952)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
29.6 × 20.3 × 28 cm (11 5/8 × 8 × 11 in.)
Accessories: metal 3/4 of a circle (1998-1-0836b); holds a cardboard strip with calibrations marked on it
Description:
A clear glass sphere, designed to focus the sun's rays, is mounted in an adjustable brass stand, which can be positioned at various angles. A semicircular mount at the rear of the globe holds a cardboard strip marked with a time scale which records the sunshine throughout the day. When the sunshine is bright, a line is burned on the card. The brass stand has an angle indicator with the engraved markings. The brass stand is fixed to a square base.
An indicator points to two engraved scales on a rounded plate mounted on the side of the instrument. One scale indicates time of year, in months. The other scale indiates the stand's angle on a semicircular scale which has zero in the center of the scale and goes to 80 in either direction.
An indicator points to two engraved scales on a rounded plate mounted on the side of the instrument. One scale indicates time of year, in months. The other scale indiates the stand's angle on a semicircular scale which has zero in the center of the scale and goes to 80 in either direction.
In Collection(s)
Signedengraved inside: CASELLA LONDON
InscribedThe instrument has a side card with the stamp: SCHOOL OF GEOGRAPHY HARVARD UNIVERSITY CAMPBELL-STOKES/ BURNING-GLASS SUNSHINE DURATION RECORDER/ Universal Type
FunctionA globe of glass acts as a burning-glass, focusing sunshine on a sheet of cardboard mounted on a holder at the rear. A semicircular mount at the rear of the globe holds the cardboard strip,which is marked with a time scale, and records the sunshine throughout the day. When the sunshine is bright, a line is burned on the card. The extent of the charring gives a rough measure of the of full or strong sunshine during the day.
Historical AttributesBlue Hill Number: BH99
Curatorial Remarks1996-1-0191 may be part of this object.
ProvenanceWas used at the Institute of Geographical Exploration, Harvard University. Previously used at the Blue Hill Meteorological Observatory. Blue Hill Number BH99 (see published references).
Published ReferencesThe Blue Hill Meteorological Observatory: The First 100 Years - 1885-1985, John H. Conover, American Meteorological Society, 1990, pg 27, Figure 11. Also see Appendix B, p.439, No. 99.