A declinometer measures the horizontal angle between the geographic and magnetic poles of the earth (also known as the declination, or variation, of the magnetic needle). This particular form was introduced by H. P. Gambey of Paris in the 1830s and remained popular in France throughout the century. This example was purchased in France and was probably produced there as well. It consists of a heavy stone base, a bar magnet supported by a thread, and microscopes at either end to read the magnet's position.
Ref: E. Mascart, Traite; de Magnetism Terrestre (Paris, 1900), p. 189-190.
Currently not on view
Object Name
Date made
ca 1830-1845
Gambey, Henri Prudence
Physical Description
metal (overall material)
marble (base material)
overall: 19 1/4 in; x 48.895 cm
Place Made
France: Île-de-France, Paris
ID Number
accession number
catalog number
Measuring & Mapping
Science & Scientific Instruments
See more items in
Medicine and Science: Physical Sciences
Data Source
National Museum of American History, Kenneth E. Behring Center

Visitor Comments

Add a comment about this object

**Please read before submitting the form**

Have a comment or question about this object to share with the community? Please use the form below. Selected comments will appear on this page and may receive a museum response (but we can't promise). Please note that we generally cannot answer questions about the history, rarity, or value of your personal artifacts.

Have a question about anything else, or would you prefer a personal response? Please visit our FAQ or contact page.

Personal information will not be shared or result in unsolicited e-mail. See our privacy policy.

Enter the characters shown in the image.