Mercury stick barometer

Title

Mercury stick barometer

Subject

Astronomy
Weather instrument
Barometer
Measuring instrument

Description

Wood, metal, glass, mercury

Housed in wooden box with glass sides, hinged wood/glass door, case is 9 ¼ x 6 ¼ x 50 ¾ inches. Originally kept in the entrance hall on the west wall, just north of the door to the transit rooms. Glass on front door broken.

Consists of mercury in a glass tube encased by chrome and brass tube. Provided with two scales read with a vernier to 0.002 of an inch and 0.05 mm. Range is 66 mm to 83 mm and 26 in to 32.5 in. Vernier moved by turning an attached wheel. Thermometer mounted on barometer measures temperature of the mercury in Centrigrade. Barometer is 45 inches long. Suspended to Mahogany board by a hanger at the top with steadying screws at the bottom cistern. White opal glass plates attached to board for reading the instruments. Inscribed on cistern with “Henry J. Green, New York,” the number 3603 on thermometer and number 3138 on the mercury scale.

The barometric pressure and the temperature were two important factors in determining the atmosphere’s index of refraction. The index of refraction was necessary for transit observations.

Creator

Henry J. Green & Company, New York

Publisher

Astronomy Department, University of Illinois, Urbana, Illinois

Date

1896

Contributor

Michael Svec

Rights

Copyright Michael Svec

Format

image/jpg

Language

English

Type

physical object

Identifier

University of Illinois Observatory Collection A129
University ID 016673, obs79

Coverage

University of Illinois Observatory, Urbana, Illinois

Files

Green Mercury Stick barometer
DSCN0229.JPG

Collection

Tags

Citation

Henry J. Green & Company, New York, “Mercury stick barometer,” University of Illinois Observatory Collection, accessed September 19, 2017, http://uiobservatory.omeka.net/items/show/15.