Aneroid barometer

Aneroid barometer in wooden box (damaged). Box also contains a thermometer with scales in C & F (held in lid). Barometer is circular with three adjustment nuts around edge, labelled: [top] HEIGHT SCALE / FEET [lower right] LOWER STATION / BAR. READING [lower left] PRESSURE SCALE. These adjust three circular scales within the face, labelled: [outer] HEIGHT IN FEET {0-7800} [next] PRESSURE SCALE {23-31} [next] BAROMETER PRESSURE / INCHES {23-31}. In centre of face is a chart headed 'TEMPERATURE SCALE / CENTIGRADE' with 'LAG %' at bottom. This gives temperature ranges for different heights from 1000 to 8000 feet. Barometer is held in box by three thumb screws. Inside lid is a printed table of imperila to metric conversions.
6" diameter.

White metal circular case 6.0" (15.2 cm) dia., containing aneroid barometer. Three knurled knobs project from the side of the case for rotating the scales. Three fixing lugs are attached to the base for securing the instrument in the wooden box by means of brass bolts.
Scales:
1. Fixed pressure scale graduated in tenths from 23 to 31
2. Height scale graduated in 50 ft divisions and marked every 100 ft from 0 to 7800 ft.
3. Fixed temperature scale.
4. Rotating pressure scale graduated in tenths from 23 to 31.
Pointers:
1. Pointer with centre axis to indicate barometric pressure.
2. Moving pointer to indicate lower station barometric reading.
3. Pointer attached to height scale.
Thermometer: (Housed in lid of box)
Centigrade scale from 0 to 57 degrees
Farenheit scale from 2 to 134 degrees

Dimensions: Barometer: 152 (face dia); 200 (max width); 50 (depth); Thermometer: 40 x 180 mm; Box: 218 x 205 x 84 mm
Label inside lid of box show comparative scale of thermometers and Weights and Measures tables.

Object Details

ID: NAV0766
Collection: Astronomical and navigational instruments
Type: Barometer
Display location: Not on display
Creator: Cary Porter Ltd
Date made: circa 1920
Credit: National Maritime Museum, Greenwich, London
Measurements: Overall: 90 mm x 203 mm x 220 mm
Parts: Aneroid barometer