Accession No
3782
Brief Description
Kew-pattern magnetometer, c. 1900
Origin
Maker
Class
magnetism; earth sciences
Earliest Date
1875
Latest Date
1925
Inscription Date
Material
metal; brass; wood; mahogany; glass; ivorine; leather; lacquer; felt
Dimensions
box length 500mm; breadth 262mm; height 262mm
Special Collection
Provenance
Donated, 19/04/1991. Initially from the sale of ‘The property of The Norman Lockyer Observatory Corporation’, Christie’s South Kensington, London, England, lot 145, 19/11/1987.
Inscription
No L-3950
Description Notes
Kew-pattern magnetometer, c. 1900
Enameled and lacquered brass Kew magnetometer. The main body tube with finder teleecope, two shades and level. Also with lower telescope with lateral ivorine scale, graduated 0 - 40, numbered by 10, graduated to 0.1. Centre with mahogany slides, box, shield and mounting for glass tube. Further arranged with a small specular mirror adjusted for azimuth and elevation by tangent screw with bubble level and located by two clamps. The whole mounted in a horizontal circle engraved with the number with chamfered silvered scale with twin verniers and magnifiers, on adjustable tripod stand. Accessories incomplete. Fitted mahogany case lined with blue felt with leather carrying strap.
Condition good; incomplete
References
Events
Description
The Kew-pattern magnetometer is a precision instrument used to accurately determine the absolute intensity of the earth’s magnetic field, in terms of units of mass, length, and time. Its design is based upon the experimental set-up devised by Carl Friedrich Gauss in the 1830s. Gauss’s experiments were conducted in a laboratory, but the increasing number of regional and national magnetic surveys in the early Victorian era created a demand for a lightweight, robust instrument that could make the same kind of accurate measurements in the field. As the name implies, the instrument was developed at Kew Observatory, first by Francis Ronalds and then by his successor as superintendant, John Welsh.
As well as being used in the field, the Kew magnetometer was also a popular instrument for use in astronomical observatories, where systematic, long-term measurement of the earth’s magnetic field was considered a standard part of observatory work. This particular instrument was used at the Norman Lockyer Observatory in Devon.
14/01/2015
Created by: Joshua Nall on 14/01/2015
FM:40574
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