Accession No
2997
Brief Description
spectroscope, Thorp's direct-vision diffraction reading type, by R. and J. Beck Ltd., English, 1930 (c)
Origin
England; London
Maker
R. and J. Beck Ltd.
Class
optical
Earliest Date
1930
Latest Date
1930
Inscription Date
Material
metal (brass, oxidised brass, alloy, silver); glass
Dimensions
length 120mm; breadth 53mm; depth 28mm
Special Collection
Provenance
Purchased from Peter Delehar, London, England, 12/1983.
Inscription
‘THORP’S
D.V. DIFFRACTION READING SPECTROSCOPE
PATENT
R & J BECK LTD’
Description Notes
Portable diffraction spectroscope; brass with oxidised brass parts (worn); slit with metal alloy jaws adjustable by a knurled ring with screw fit cover; push focus; bright line micrometer; side tube provides line push focus moved by screw on opposite side, silvered drum head divided 0-100 by 1; reading glass.
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:44805
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