Abstract
THE beautiful illustrations of stress in a dielectric in an electric field, due to Dr. Kerr, have been modified and amplified by Messrs. Rücker and Boys, and were shown to a large audience at the Institution of Electrical Engineers on March 22, and again at the soirée of the Royal Society. The dielectric they used was carbon bisulphide (CS2), and the beam of light passed through about four inches of the liquid. The presence and intensity of the electric field was evident to all by the brightness of the screen. They showed experiments to illustrate the fact that the repulsion of similarly electrified bodies may be regarded as an attraction between each of them and surrounding objects. They have devised an experiment visible to a large audience to show that in an electric field the structure of the CS2 becomes crystalline—that is, the optical properties along and transverse to the electric lines of force are different; in other words, the velocities of propagation of light vibrations differ when parallel and perpendicular to the lines of force, contrary to the view formerly held on the Continent that the effect is due to unequal expansion. They were able to increase the stress so that the liquid displayed colours even to the green of the second order; and by observing the spectrum of the light passing through the field, black bands enter at the violet end and traverse its whole length as the potential rises. Faraday's experiments and speculations, Maxwell's mathematics and theories, are rapidly becoming acknowledged facts; and the apparatus of Messrs. Riicker and Boys will materially assist in spreading a knowledge of the confirmation which those theories receive from the work of Kerr and Quincke.
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Our Electrical Column . Nature 38, 161–162 (1888). https://doi.org/10.1038/038161c0
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DOI: https://doi.org/10.1038/038161c0