aneroid barometer
Date: circa 1910
Inventory Number: 5117
Classification: Barometer
Maker: Andrew J. Lloyd Company (fl. 1890 - 1930)
Inventor: Taylor Instrument Companies (1851 - 1992)
User: Department of Geology and Geography, Harvard University (1890 - 1961)
Cultural Region:
Place of Origin:
Dimensions:
9.5 × 6.5 × 2 cm (3 3/4 × 2 9/16 × 13/16 in.)
Description:
Watch pattern aneroid barometer, in a gift case with a knob and loop at the top, and a silvered metal dial, engraved. The glass cover moves with the revolving altitude dial, which is on a raised rim around the inner scale. The scale reads from 20-31 inches, and from 0-12,000 feet.
The face indicates that this instrument is compensated for the effects of temperature on barometric readings, and there is a scale for feet and for inches. A very thin needle indicates the reading.
The face indicates that this instrument is compensated for the effects of temperature on barometric readings, and there is a scale for feet and for inches. A very thin needle indicates the reading.
Signedon face: ANDREW J. LLOYD CO. / BOSTON
Inscribedon face, near needle: COMPENSATED/ "Tycos"
FunctionAneroid barometers were used to measure atmospheric pressure and altitude, and were much more convenient than mercury barometers since they did not use any kind of liquid. Instead, a small, partially evacuated and flexible metal capsule inside the casing, which is kept from collapsing by a small spring, contracts and expands in accordance with the surrounding air pressure. The minute changes in the volume of the capsule are translated through internal clockwork to the dial on the face of the barometer, and can be read against the accompanying scales.
One of the major benefits of this kind of barometer was its portability. They could be made extremely small, and were much more easily transported since they did not contain mercury. The downside of their size, however, was the fact that scales had to be considerably contracted in order to fit on the instrument, but extend far enough to be useful.
One of the major benefits of this kind of barometer was its portability. They could be made extremely small, and were much more easily transported since they did not contain mercury. The downside of their size, however, was the fact that scales had to be considerably contracted in order to fit on the instrument, but extend far enough to be useful.
ProvenanceReceived from R. Novius, Department of Geology, Harvard University.