The routine measurement of sunshine was started in London, in 1853 by J.F.Campbell. His instrument was modified in 1880 by Stokes into the ubiquitous Campbell-Stokes recorder which is still the official sunshine recording method in UK. The instrument has a mounted glass sphere which focuses the suns rays onto a thick card, burning a hole when the sun is shining. The passage of the sun across the sky translates into a linear burn pattern along the card which may be analysed by the observer to give measurements of sunshine duration.