Accession No

1900

Brief Description

three-element wedge prism, 2nd half 18th Century

Origin

Maker

Class

optical

Earliest Date

1750

Latest Date

1800

Inscription Date

Material

glass; metal (brass); cloth (velvet); hide; wood

Dimensions

case length 97mm; breadth 46mm; thickness 22mm

Special Collection

Cavendish collection

Provenance

Transferred from the Cavendish Laboratory, University of Cambridge in 1974.

Inscription

Description Notes

3-element multiple wedge prism. Each element in brass mount connected by brass screws. Brass rod mount with connecting rod held by screw clamp. In fitted black skin-covered, green velvet-lined box.

Condition: fair (lid of box detached); 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:43183