artificial horizon
Date1850-1900
Inventory Number5327a
ClassificationArtificial Horizon
Subject
Maker
English
?
User
Department of Geology and Geography, Harvard University
1890 - 1961
Cultural Region
Dimensions1.4 x 12.9 x 12.9 cm (9/16 x 5 1/16 x 5 1/16 in.)
storage: 1.5 x 13 x 13 cm (9/16 x 5 1/8 x 5 1/8 in.)
storage: 1.5 x 13 x 13 cm (9/16 x 5 1/8 x 5 1/8 in.)
Material
Accessoriesmercury jar (5327b)
DescriptionA shallow trough consisting of two wooden disc sections that turn together, with the lower portion hollowed out and covered with metal foil.
Signedunsigned
Inscribedwritten with pencil on both discs: 3
FunctionThis is a portable device that replaces the horizon when taking measurements with a sextant on land.
Instead of measuring angles from the height of a celestial body to the horizon as one would do on the ocean, what was done on land is to measure the angle between the celestial body and its reflection on a horizontal surface, which will give twice the angle to the horizon. One of the most used means as a horizontal reflecting surface was a mercury trough.
This model is highly portable and comes with a bottle of mercury with a protective wooden shell (5327b).
Instead of measuring angles from the height of a celestial body to the horizon as one would do on the ocean, what was done on land is to measure the angle between the celestial body and its reflection on a horizontal surface, which will give twice the angle to the horizon. One of the most used means as a horizontal reflecting surface was a mercury trough.
This model is highly portable and comes with a bottle of mercury with a protective wooden shell (5327b).
ProvenanceFrom the Department of Geology and Geography, Harvard University.
L. Casella
Date: late 19th century
Accessories: brown leather case with belt and buckle closure
Object number: 5322
American
Date: late 19th century
Accessories: mahogany box with brass hinges, handle, lock, hooks; iron bottle filled with mercury
Object number: 5257
L. Casella
Date: circa 1860
Accessories: two brass spirit levels on legs; mahogany case
Object number: 5255
American
Date: late 19th century
Accessories: mahogany box
Object number: 5325
George Whitbread
Date: circa 1850
Accessories: article containing description and operating instruments (in instrument file)
Object number: 5323
Ziegler Electric Company
Date: 1890-1930
Accessories: part of a series of four Leyden jars that comes in a box with 4 holes cut in and knob. The series includes an extra lid and a two photographs of the jar 1997-1-0677a with their negative (in Kodak safety film)
Object number: 1997-1-0677d
C. F. Casella & Co. Ltd.
Date: circa 1910
Accessories: lens cap, moving jar containing mercury (do not open), one other item
Object number: 5139
L. E. Knott Apparatus Company
Date: 1900-1930
Accessories: part of a series of four Leyden jars that comes in a box with 4 holes cut in and knob. The series includes an extra lid and a two photographs of the jar 1997-1-0677a with their negative (in Kodak safety film)
Object number: 1997-1-0677c
American
Date: 1850-1900
Accessories: part of a series of four Leyden jars that comes in a box with 4 holes cut in and knob. The series includes an extra lid and a two photographs of the jar 1997-1-0677a with their negative (in Kodak safety film)
Object number: 1997-1-0677a
American
Date: 1850-1900
Accessories: part of a series of four Leyden jars that comes in a box with 4 holes cut in and knob. The series includes an extra lid and a two photographs of the jar 1997-1-0677a with their negative (in Kodak safety film)
Object number: 1997-1-0677b
See also/See also
