Antique Negretti and Zambra Precision Pressure Gauge. England, Circa 1930

Antique big-sized Negretti & Zambra manometer, made in England circa 1930 and in very good condition. This delicate and amazing instrument was used to measure small gaseous pressures in confined spaces such as ducts, wind tunnels or chimneys. The fluid could be water, oil or mercury. The tube must have a slight incline when used, which can be established leveling the instrument with the help of the bubble level mounted inside the case. The manometer that we can see in the images is composed of a long rectangular case, made of solid oak wood and disposed horizontally on a wooden plank with two small adjustable brass pillars. The box mounts a front glass door so it looks like a showcase; screwed to the back of the case we can see the glass tube. Its left end is connected to a fluid reservoir, and the right one ends at the top of the case. At the top of the manometer we can see two brass ports connected to both ends of the tube. This is also attached to a brass graduated scale with the engraved manufacturers name: NEGRETTI & ZAMBRA LONDON. To the left of the manometer we can also see a brass plate with an engraved and black-enameled inscription in capital letters. It warns the user not to ever disturb the setting of the spirit level, and says that in the event of breakage the instrument must be sent back to the manufacturers for its recalibration. All the component parts that make up the manometer are in fine condition the wood shows off its gorgeous golden shade and dark veneer, the glass parts are original and the brass pieces are finely preserved too. Decorative and nostalgic, this big-sized Negretti & Zambra antique precision manometer is bound to shine in any stylish space. Measurements: Base: Width: 20 in / 50 cm. Depth: 5.8 in / 14 cm. Case: Width: 30.4 in / 76 cm. Height: 6.4 in / 16 cm. Depth: 2.8 in / 7 cm. Manometers Height: 10 in /25 cm.Negretti & Zambra History Negretti & Zambra was founded in 1850 by Henry Negretti (1818-1879) and Joseph Zambra (1822-1897), both born in Italy, to manufacture scientific (philosophical) and optical instrument. The business was located in London and it also included a photo studio. The company created by Negretti and Zambra would eventually be appointed official opticians and scientific instrument makers to Her Majesty Queen Victoria and Prince Albert, and later to King Edward VII. They also made instruments for the Royal Observatory and the British Admiralty. The company also commissioned different photographers to document relevant events such as the Opium War which confronted China and Great Britain from 1839 and 1942.