This is lovely mid-20th century wall barometer by Negretti & Zambra, London. It is engraved with the serial number R/2001 and the entwined N & Z logo device. The barometer bezel is 180mm in diameter and the highly polished walnut case is 287mm overall diameter.
A nice working instrument by a world renowned manufacturer.
Large 1950s Wall Barometer by Negretti & Zambra