This is the commonly used barograph at synoptic weather stations. Made by Casella, this particular instrument is the updated version which uses the cantilever movement. The mechanical magnification provided by the lever transmission is more than twice that of a standard barograph and the drum diameter is also larger than average so that the time scale is expanded. This enables the observer to record minor but significant atmospheric pressure movements, particularly during thunderstorms and even certain volcanic disturbances. 
The moving parts are mounted on a substatial aluminium alloy base casting with a stove enamel finish. A lift-off cover of transparent acrylic fits over the base and allows maximum visibility of the chart.
A quantity of special charts is included together with
a fresh bottle of special blue or red recording ink and a reprinted
pamphlet by Negretti & Zambra describing operating
instructions and how to interpret typical chart recordings.
 
332mm wide x 174mm deep x 240mm high