Accession No
2998
Brief Description
prism, 2nd 1/2 18th C
Origin
Maker
Class
optical
Earliest Date
1750
Latest Date
1800
Inscription Date
Material
glass; metal (brass)
Dimensions
length 210mm; breadth 38mm; depth 15mm
Special Collection
Provenance
Purchased from Peter Delehar, London, England, 1983.
Inscription
Description Notes
105˚ glass prism; brass mounts at either end with turned brass handles.
Condition
References
Events
Description
Prism
A prism consists of a translucent piece of glass or crystal, usually triangular in cross section, which is used to separate light into a spectrum of its separate colours.
The instrument works because different wavelengths of light are refracted (bent) by different amounts as they enter and leave the prism; the shorter wavelengths (towards the blue end of the spectrum) are refracted by the greatest amount, and the longer wavelengths (towards the red end) are refracted the least. This spreads out normal white light, which is a mixture of all the different colours, into its constituent parts and produces the rainbow effect of a spectrum.
18/10/2002
Created by: Saffron Clackson on 18/10/2002
FM:43409
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