Accession No
2842
Brief Description
portable direct-vision spectroscope, by John Browning, English, c. 1890
Origin
England; London
Maker
Browning, John
Class
optical
Earliest Date
1890
Latest Date
1890
Inscription Date
Material
metal (brass); glass
Dimensions
case length 93mm; diameter 21mm
Special Collection
Provenance
Purchased from Christie’s, South Kensington, London, England; lot 222, 29/04/1982.
Inscription
‘John Browning,
London’
Description Notes
Portable direct-vision spectroscope, by John Browning, English, c. 1890.
Brass direct-vision spectroscope, slit brass jaws, width adjustable by knurled ring on barrel. Sliding cover for slit. Push focus with slit on long draw tube. Screw-in eyestop. Slip case.
References
Events
Description
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. Direct vision spectroscopes consist of a series of prisms of different refractive indices arranged to produce dispersion of light without deviation.
18/10/2002
Created by: Saffron Clackson on 18/10/2002
FM:44822
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