For sale a pocket weather forecasting barometer by Negretti & Zambra. This extraordinarily rare collectors piece is comprised of two inch dial pocket barometer with scale reading for 28 to 31 inches of barometric pressure and an extremely fine blue steel pointing hand. The dial is intricately designed with three concentric rings, the fixed main dial running around the outer circumference bears the barometric pressure reading and a separate scale at the base for indicating the direction of the wind at the time the reading is taken. The middle dial is operated by turning the fine knurled brass bezel and allows the user to set the needle against the correct wind direction at on the base scale. In turn this movement adjusts the letters engraved under the central dial in order to prepare for the barometer reading.
The central dial has a small scale at the top which is used to align it with the current barometer reading. This is executed by turning the pocket watch winder mechanism contained within the hanging loop. This action in turn reveals a series of letters through three square cut outs which can be read in conjunction with the superbly engraved key on the back of the pocket barometer. It also has another serial no: R/1558 below with Negretti & Zambra engraved in full. The three cut out sections on the central dial engraved, Rise, Steady & Fall relating to the movement of the barometer pressure at the time of the reading, this ensures that the observer uses the correct letter to read the forecast.
The three quarter inch deep case is engraved with an altitude in feet scale around the circumference which is operated by twisting a bezel at the back of the case allowing the barometer hand to be adjusted to the appropriate height above sea level thus providing accurate measurement in the given area of the country in which it is being operated. The hinged case is covered with morocco leather with push clasp at the side, the interior is further provided with a green silk velvet lining to ensure that the barometer is protected. The lid is also fitted with an ivorine Negretti patent weather forecasting key which allows the observer to take readings without the need to remove the barometer from the case to observe the back, a feature that shows the amount of thought that went into the design of this fine instrument. The barometer retains almost all of its original gilt lacquer and remains in perfect working order.Negretti & Zambras patent weather forecasting instruments were a revelation in their time, the helpful yet somewhat confusing barometer indications produced by Admiral Fitzroy some years earlier had helped to domesticate the barometer into the family home but unless some knowledge and regular discipline in reading the instrument was exerted, the barometer was only ever a current reading of barometric pressure. With this simple yet highly effective tool, the weather could be forecast with a good deal of accuracy in seconds. This pocket barometer represented one of the most luxurious offering by the company during the period and effectively provided the same features as its larger cased counterpart but in a size that could be carried in the waistcoat pocket. They are rarely seen today and even more seldom seen in this condition. Negretti & Zambra were a leading name in the production and retailing of meteorological and scientific instruments and had a company history dating back to 1850 although their parents were amongst those Italian emigres that bolstered the British meteorological instrument making industry at the turn of the century. Throughout their long and esteemed history they exhibited at British and international industrial fairs and became makers to both Queen Victoria and Edward VII. Owing to changes in the business, the firm ceased the public retailing of scientific instruments sometime around the late 1960s and continued with a focus on the aviation industry in numerous guises until its eventual liquidation in the year 2000. They are today perhaps the most collected of the scientific instrument firms which bears testament to the quality of their work.
Jason Clarke Antiques are happy to discuss carriage, condition or for any other queries, alternatively, you can also message us and we will endeavour to come back to you as soon as possible. The item "POCKET WEATHER FORECASTING ANEROID BAROMETER BY NEGRETTI & ZAMBRA LONDON" is in sale since Tuesday, May 11, 2021. This item is in the category "Antiques\Science/Medicine\Scientific Instruments".
The seller is "jason750_1" and is located in newbury, Berkshire. This item can be shipped to United Kingdom.