This is a photographic sunshine recorder invented by Mr J B Jordan in 1885 & manufactured under license by Negretti & Zambra. This is an early example – number 905. The instrument works by the sun’s rays ‘falling upon a specially sensitized chart’ placed inside the drum thereby making a record in a photographic manner. See the N & Z catalogue extract circa 1912. I also have a small quantity of the special charts & other models by Negretti & Zambra. Please contact me for more details.