Accession No
2840
Brief Description
portable direct-vision spectroscope, by John Browning Ltd, English, early 20th Century
Origin
England; London; 138 Strand
Maker
John Browning Ltd.
Class
optical
Earliest Date
1920
Latest Date
1920
Inscription Date
Material
metal (brass); glass
Dimensions
length 99mm; maximum diameter 19mm
Special Collection
Provenance
Purchased from Christie’s, South Kensington, London, England; lot 230, 29/04/1982.
Inscription
‘JOHN BROWNING LTD
138 STRAND
LONDON
7615’
Description Notes
Portable direct-vision spectroscope, by John Browning Ltd, English, early C20th.
Brass direct-vision spectroscope. Glazed cover for slit, width adjustable by knurled ring. Push focus, with slit on long draw tube. Glazed cover for eye-end. Prism assembly loose inside.
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. 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:44806
Images (Click to view full size):
