Images(3)

solar light source

Date1850-1880

Inventory Number2001

ClassificationLight Source

Subject

User Louis Jules Duboscq French, 1817 - 1886

Maker Department of Physics, Harvard University founded 1884

Cultural Region

Place of Origin

Dimensions55.3 x 31 x 28.4 cm (21 3/4 x 12 3/16 x 11 3/16 in.)

Material

DescriptionLarge circular mirror mounted on a gearing system linked to the drum at the base of the instrument. The gears inside the drum are activated at a distance by means of two rods equipped with Cardan joints (only one joint is showing here, the other one and the rods are missing). The instrument is supported by a heavy tripod stand.

Signedon instrument: J. Duboscq / à Paris

FunctionThis is what Duboscq called a "porte-lumière solaire", a light source created by sunlight. This is not a heliostat. The mirror is oriented by hand at a distance with the help of rods attached to Cardan joints and fixed to the base of the instrument. It could have been used with a heliostat though, as a second mirror made to redirect the sunlight coming from the heliostat.

For a representation of this instrument in one of Duboscq's trade catalogue, see the following website.

ProvenanceFrom the Department of Physics, Jefferson Laboratory, Harvard University.