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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