aneroid barometer
Date: circa 1900
Inventory Number: 5105
Classification: Barometer
Subject:
Maker: T. Cooke & Sons (1837 - 1922)
User: Nathaniel Southgate Shaler (1841 - 1906)
Donor: Jay Backus Woodworth (1865 - 1925)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
6.5 × 6.5 × 2.5 cm (2 9/16 × 2 9/16 × 1 in.)
case: 7.5 × 7.5 × 3.5 cm (2 15/16 × 2 15/16 × 1 3/8 in.)
Accessories: cylindrical case
Description:
Aneroid barometer consisting of a brass disc with a glass face. The face is inscribed with the makers information, and also includes an altitude scale extending to 8,000 feet, in 20 foot divisions, as well as a pressure scale numbered from 23-31 inches. It has a knob and loop at the top.
Signedon face: T Cooke & Sons / Patent / 31 Southampton St. / STRAND / LONDON / 232 / Compensated
Inscribedon face: pressure scale from 23-31 inches, in 1/5 inch increments
on face: altitude scale to 8,000 feet, in 20 foot increments
on face: altitude scale to 8,000 feet, in 20 foot increments
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.
This particular barometer can be called an altimeter as one of its scales is in feet (of altitude above sea level).
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.
This particular barometer can be called an altimeter as one of its scales is in feet (of altitude above sea level).
ProvenanceNote on inside cover: Professor Shaler's Aneroid Barometer Donated by Professor J.B. Woodworth.