Accession No
3425
Brief Description
four-prism train table spectroscope, by John Browning, English, c. 1880
Origin
England; London; 63 Strand
Maker
Browning, John
Class
optical
Earliest Date
1880
Latest Date
1880
Inscription Date
Material
wood (mahogany and two others); metal (brass, oxidised brass, at least one white metal); glass; cloth (baize)
Dimensions
maximum length 830mm; breadth 330mm; height 335mm box breadth 390mm; height 435mm; depth 350mm
Special Collection
Provenance
Purchased from Phillips, London, England; lot 141, 10/09/1986. Purchased with the assistance of Grant in Aid from the PRISM Fund.
Inscription
‘John Browning,
62, Strand,
London.’ (prism plate)
Description Notes
Four-prism train table spectroscope, by John Browning, English, c. 1880.
Four-prism train table spectroscope in brass, oxidised brass, white metal and glass. Tribrach base set on mahogany stand; central brass pillar supports oxidised brass circular plate with silvered scale divided [0] - 360˚, numbered by 10˚, subdivided to 15´; vernier reading to 15´´, with reading microscope. Moving on radial arms around the milled rim of this plate are the brass telescope, collimator and micrometer. The collimator has a slit, adjustable by screw with micrometer divided 0 - [10], numbered by 1, subdivided to 10´. The micrometer has a frosted glass screen with scale divided 0 - [3], numbered by 1. Telescope with screwfit eyeend with pushfit eyepiece, screwfit objective, crosshairs and knurled brass screw for adjusting focus; movement of the telescope around the circle is adjusted by a clamp and tangent screw with a drumhead micrometer divided 0 - [100], numbered by 10, subdivided to 1. Mounted on an oxidised brass circle above the main plate is the double prism train, with reflecting prisms at the two ends.
Two spare eye-ends. The telescope and collimator can be removed for storage.
Mahogany box with brass hinges hook fastener and lock (no key); brass and wood carrying handles. The wooden base of the spectroscope slides into the base of the box.
Condition good; complete.
References
Events
Description
Spectroscope
In 1814 Joseph von Fraunhofer noticed that the sun’s spectrum, when dispersed by a glass prism, is crossed by hundreds of fine dark lines. These lines could be used to determine the chemical composition of the sun, stars and many other substances by spectral analysis. The first photograph of the spectrum of a star (Vega) was made by Henry Draper using a spectroscope in 1872.
There are various different forms of spectroscope, but all use a slit and collimator to make a parallel beam of light, a prism for dispersing different wavelengths and a telescope to observe the dispersed spectrum.
18/10/2002
Created by: Saffron Clackson on 18/10/2002
FM:44777
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