A course of six lectures on the various forces of matter and their relations to each other / by Michael Faraday ; edited by William Crookes.

  • Michael Faraday
Date:
1860
Catalogue details

Licence: Public Domain Mark

Credit: A course of six lectures on the various forces of matter and their relations to each other / by Michael Faraday ; edited by William Crookes. Source: Wellcome Collection.

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    between particle and particle. Whether you have this mechanical power of straining, or whether we take other means, we get the same result, and, indeed, I will show you by another experiment that if we heat the glass in one part it will alter its internal structure, and produce a similar effect. Here is a piece of common glass, and if I insert this in the path of the polarised ray, I believe it will do nothing. There is the common glass [introducing it] —■ no light passes through—the screen remains quite dark; but I am going to warm this glass in the lamp, and you know yourselves that when you pour warm water upon glass you put a strain upon it sufficient to break it sometimes —something; like there was in the case of the Prince Eupert's drops. [The glass was warmed in the spirit lamp, and again placed across the ray of light.] Now you see how beautifully the light goes through those parts which are hot, making dark and light lines just as the crystal did, and all because of the alteration I have effected in its internal condition; for these dark and light parts are a proof of the presence of forces acting and dragging in different directions within the solid mass
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