TONY BUXTON / SCIENCE PHOTO LIBRARY TONY BUXTON / SCIENCE PHOTO LIBRARY
Campbell-Stokes sunshine recorder. This instrument consists of a glass sphere which focuses the sun's rays onto a card underneath it, burning a trace along the card whenever bright sunshine occurs. The length of the trace indicates sunshine duration. As it only records bright sunshine, hazy conditions or early morning or late evening hours are not recorded. No distinction is made between winter and summer sunshine. This particular Campbell-Stokes recorder has been mounted on a wooden support. Photographed in the Hoggar Mountains of Central Sahara, Algeria.
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