Hostname: page-component-586b7cd67f-g8jcs Total loading time: 0 Render date: 2024-11-24T16:40:57.748Z Has data issue: false hasContentIssue false

2. On the Optical Properties of Greenockite, by Sir David Brewster, in a letter to Lord Greenock

Published online by Cambridge University Press:  16 March 2015

Get access

Extract

Greenockite has the form of a regular six-sided prism, with pyramidal summits, the faces of the pyramid being inclined 36° 20′ to their base. The pyramids are sometimes truncated on their summit.

The crystallization is often composite.

The index of refraction of Greenockite is 2.6882, corresponding to the middle of the green space, and to the ordinary ray. Hence Greenockite exceeds the Diamond in refractive power, and also chromate of lead, which I had found to surpass the diamond in this respect.

The double refraction of Greenockite is comparatively small, which is not usual in substances of a high refractive power. It is so small, indeed, that owing to its great dispersive power it is exceedingly difficult to separate the two images.

Type
Proceedings 1840–41
Copyright
Copyright © Royal Society of Edinburgh 1844

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)