Campbell–Stokes sphere sunshine recorder by Casella of London, mounted on golden oak base, circa 1930. Campbell Stokes Sunshine recorder (sometimes called a Stokes sphere) by Casella, London, No.8351. The 4inch glass sphere is mounted in a brass arc adjustable for inclination. The brass arc is mounted in a heavy cast iron tripod base. The Campbell–Stokes recorder is a type of sunshine recorder. 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. The unit is designed to record the hours of bright sunshine which will burn a hole through the card.