This open scale barograph was the standard pressure recording instrument used at synoptic weather stations throughout the UK and Commonwealth from the late 1930s for a further over 40 years. Made by Negretti & Zambra to a British Meteorological Office design it has a higher magnification so that its sensitivity is more than double that of the standard pattern.
This particular barograph can be dated to circa 1965.
The sensing unit, of the belows type, is compensated for temperature. Its expansion and contraction is transmitted to the pen through a system of levers with a magnification in the order of 1:70. The sensing unit, lever system and recorder clock are mounted on a specially chromed metal base. The all-glass metal framed lift off lid has had the similar recent chromed treatment creating an exceptional contemporary instrument with highly sensitive and accurate recording which would grace any office or home environment. A quantity of  Met Office recording charts together with a fresh bottle of recording ink will be supplied. An extract from the Met Office Weather Instruments reference book describing this instrument in great detail will be also be included.
370mm wide x 265mm high x 225mm deep.
(Please note, the curious marks across the chromework in the pictures are simply reflections!)