Object Description
A mid twentieth century Campbell–Stokes sunshine recorder, by Casella & Co, London.
Pattern: Mk III C 45- 65 (latitudes 45° – 65°, North or South). 4 inch glass sphere.
Serial number: 6218
Marked: CASELLA LONDON MADE IN ENGLAND 6218
Height: 24 cm.
Width: 19.5 cm.
Depth: 18 cm.
Weight: 5.35 kilos.
For similar Casella sunshine recorders see the collections of:
Science Museum, London. OBJECT NUMBER:1995-820.
The National Museum of the Royal New Zealand Navy, Torpedo Bay, New Zealand.
The Campbell–Stokes sphere is used to record sunshine. It was invented by John Francis Campbell in 1853 and modified in 1879 by Sir George Gabriel Stokes.
The original design by Campbell consisted of a glass sphere set into a wooden bowl with the sun burning a trace on the bowl.
Stokes’s refinement was to make the housing out of metal and to have a card holder set behind the sphere.