On some properties of light. By David Brewster, LL. D. F. R. S. Edin. In a letter to Sir Humphry Davy, F. R. S

• Published in: Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 1832
• Subjects: Brewster; Malus; Iceland
• Online Access: http://dx.doi.org/10.1098/rspl.1800.0268; https://royalsocietypublishing.org/doi/pdf/10.1098/rspl.1800.0268

The author, having been for some time past engaged in a course of experiments on the refractive and dispersive powers of different substances, the details of which are intended for future publication in a separate work, confines himself, at present, to a relation of such of his results as have most of novelty or importance. After repeating the experiments that have been made by others on the properties that light acquires by transmission through Iceland-spar, and upon the corresponding properties of reflected light originally discovered by Malus, and by him termed polarization, Dr. Brewster observed a singular appearance of colour on each side of a luminous object, viewed through a thin slice of laminated agate. Upon examination of these coloured images through a prism of Iceland-spar, this light was found to be similarly polarized, so as to appear or disappear accordingly as the laminae of the agate were parallel or transverse to the principal section of the spar. He found also that the colourless light transmitted directly through the agate, and from which the coloured rays had been separated, was polarized as well as the coloured rays, appearing and disappearing alternately with them during the revolution of the spar. And accordingly when light previously polarized by reflection was received upon the agate, its transmission or reflection depended on the relative position of the laminae of the agate to the plane of reflection; for when these were at right angles to each other, no light whatever was transmitted. In the same manner light polarized by transmission through the laminated agate, manifested the usual properties of light so affected by other means.