Accession No
2916
Brief Description
portable direct-vision spectroscope, by John Browning, English, 1880 (c)
Origin
England; London; 63 Strand
Maker
Browning, John
Class
optical
Earliest Date
1880
Latest Date
1880
Inscription Date
Material
metal (brass); glass; wood; hide (leather); cloth (velvet)
Dimensions
case length 96mm; breadth 43mm; height 27mm
Special Collection
Provenance
Purchased from Christie’s, South Kensington, London, England, 09/12/1982.
Inscription
‘John Browning
London’ (signed)
‘JOHN BROWNING
63. STRAND
LONDON’ (in box)
Description Notes
Portable direct-vision spectroscope, by John Browning, English, c. 1880
‘Browning’s New Miniature Spectroscope, with Micrometer’ small direct vision spectroscope. Brass. Slit adjustable by milled ring. Sliding-focus eye end with screw-in eyepiece. Eye-end also carries subsidiary tube with micrometer scale on glass (sliding focus) reflected into field of view by prism. Covers for slit & subsidiary tube. Fitted wooden case covered with leather and lined with velvet.
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:44823
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