Early Twentieth Century Negretti & Zambra Barograph Model D9167 Manufactured Under Licence From Short & Mason
A rare and unusual early twentieth century Negretti & Zambra Barograph No D 9167 manufactured under licence from Short & Mason with bevelled glass case and crackle painted metal base.
The barograph contains a 12 chambered aneroid mechanism with a range of 28.5 to 31 inches of atmospheric pressure combined with a drum that has a seven day clockwork mechanism accessed and wound through the top of the drum. Both are in good working order.
The function of the instrument is perhaps best described by Negretti & Zambra’s themselves, the following is an extract from their 1886 catalogue where an earlier model was offered for sale.
“This instrument registers automatically with ink upon a ruled paper chart attached to a vertical cylinder revolved for seven days by means of a clock movement inside it. The fluctuations of atmospheric pressure act upon seven aneroid vacuum chambers connected by an exceedingly simple mechanical contrivance to a long lever arm carrying the pen, by which a magnified diagram is produced upon the paper on the cylinder of the rise and fall or present height of the barometric column. These papers are ruled to represent inches and tenths of the mercurial barometric scale.”
The instrument bears two labels reflecting the following wording:
“Manufactured under licence from Short & Mason Ltd”
“Negretti & Zambra London – R/40058 – Range 28.5/31 ins – Made in England – No D9167”
Inside the drum it also bears a registration stamp of 39846
Both Negretti & Zambra and Short & Mason were leading names in the production of meteorological and scientific instruments and have company histories dating back to the mid nineteenth centuries. Both exhibited at British industrial fairs throughout and Negretti & Zambra became makers to both Queen Victoria and Edward VII.
It is testament to Short & Mason’s competence that a company such as Negretti & Zambra would manufacture to their designs under licence. An unusual circumstance that I have not encountered before and a superb barograph.