Accession No

2332

Brief Description

water prism, French, mid-19th Century

Origin

France

Maker

Class

optical

Earliest Date

1825

Latest Date

1875

Inscription Date

Material

metal (brass); glass

Dimensions

diameter 200mm; height 295mm

Special Collection

Provenance

Purchased from Peter Delehar, London, England, 22/11/1979.

Inscription

Description Notes

Water prism, brass. Two brass plates form the ends of the ‘prism’, the refracting sides being pivoted brass frames, glazed, moving over scales on the side plates, graduated 0 - 40 by 1˚. the top is open. the prism mounted on a brass pillar stand, with a basin for catching water beneath and a flat tripod base with three levelling screws.

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:43407