A fine scarce lacquered brass five glass mahogany cased combination barograph and barometer with thermometer by Negretti & Zambra c1915

Drum Barograph and Barometer by Negretti & Zambra c1915


Image of Negretti & Zambra Barograph with Dial c1915Antique barograph having 3½” x 3⅝” drum with seven day duration, platform escapement, captive key, hinged paper clip, top nut keeper and lid. The barometer section raised on four turned pillars, blued screws and pivots, polished cross shafts, eight cell pressure sensor, polished recording arm.

Fusee driven barometer with 4⅜” open centre dial, the upper part marked “Stormy, Rain, Change, Fair, Very Dry” and calibrated in inches of mercury with a range from 28–31″, divided to 10ths and 50ths, the lower portion with curved thermometer calibrated in degrees Fahrenheit and Centigrade with ranges 0–140 & -10–60 respectively, blued steel pointer.

The long lacquered brass chassis with adjustment knob and arrestor bar. Mahogany case with base mounted ink station, original bottle and dipper, frieze drawer. The lid with five bevelled glasses.

We have yet to aquire a barograph that did not require a total overhaul – these are very delicate instruments. The very nature of a barograph – essentially a mechanical amplifier – demands that all aspects are set to optimum in order to obtain good results. This barograph has been the subject of a complete rebuild, cleaned, conserved, reset and realigned, pressure tested to full scale deflection. New Vavasseur Antiques recording arm and nib.

At first glance most of these instruments appear to be very similar, and the differences that might set one instrument as very good and another as poor are subtle. This is a first quality piece, manufactured at a time when the maker was at the top of its game. Working on these fine instruments is a privilege and a pleasure.

As a first quality instrument, it has an eight cell pressure sensor, the rare benefit of a curved thermometer set to the barometer dial, and is housed in a fine quality case. As the chart below demonstrates, its accuracy is absolutely spot on.

Though unsigned, it would be hard to find a better example of these increasingly difficult to find instruments.

Dimensions: 14¾” wide x 8 ¾” high x 9″ deep

Stock No: BG0970

Price £ 1750

Image of Negretti & Zambra Barograph with Dial c1915 Test Results

 

Image of Negretti & Zambra Barograph with Dial c1915
Image of Negretti & Zambra Barograph with Dial c1915
Image of Negretti & Zambra Barograph with Dial c1915
Image of Negretti & Zambra Barograph with Dial c1915
Image of Negretti & Zambra Barograph with Dial c1915
Image of Negretti & Zambra Barograph with Dial c1915
Image of Negretti & Zambra Barograph with Dial c1915
Image of Negretti & Zambra Barograph with Dial c1915

Image of Negretti & Zambra Barograph with Dial c1915
Image of Negretti & Zambra Barograph with Dial c1915
Image of Negretti & Zambra Barograph with Dial c1915
Image of Negretti & Zambra Barograph with Dial c1915





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