Accession No
0120
Brief Description
triple prism, English, 1800 (c)
Origin
England
Maker
Class
optical
Earliest Date
1800
Latest Date
1800
Inscription Date
Material
glass; metal (brass)
Dimensions
length 128mm; breadth 36mm; thickness 22mm
Special Collection
Robert Whipple collection (?)
Provenance
This object was found uncatalogued in the collection, and hence its association with Robert Whipple is uncertain. Initially assigned the number U187, a note in the accession register, initialled DJB, 06/1975, records its reassignment to this number.
Inscription
Description Notes
Triple or achromatic multiple prism. Three hinged elements, each in brass frames, outer two of green-tinged crown glass, central of white-tinged flint glass. Outer prisms each have knurled clamping screw.
Condition: good/fair; complete.
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:42673
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