This is a nice straightforward working barograph in a mahogany case by well known manufacturers, Negretti & Zambra Ltd., London circa 1935. The movement consists of four sets of spun diaphragms mounted on a brass baseplate. The five-glass lid is hinged on the left side with a neat swing clip to secure. 
The instrument was originally offered in weekly or daily clock rotation (this example is weekly)- see picture extracted from the Negretti & Zambra trade catalogue, M2, circa 1930.
A quantity of weekly charts are included together with a fresh bottle of recording ink and a reprinted pamphlet by Negretti & Zambra detailing operating instructions and how to interpret various barometric recordings.
355mm wide x 220mm deep x 195mm high.