Six lectures on light [electronic resource] : delivered in the United States in 1872-1873 (1882)
Tyndall, John, 1820-1893, Parsons, John Herbert, Sir, 1868-1957, donor, University College, London. Library Services, University College, London. Library Services · London : Longmans, Green, and Co. · leaf 132
in the propagation of any ray is the elasticity at right angles to the direction of propagation. In Iceland spar there is one direction round which the crystalline molecules are symmetrically built. This direction is called the axis of the crystal. In consequence of this symmetry the elasticity is… … at right angles to it. Consider, then, a system of waves crossing the crystal in a direction perpendicular to the axis. Two directions of vibration are open to such waves: the ether particles can vibrate parallel to the axis or perpendicular to it. They do loth, and hence immediately divide…
Boyle, Robert, 1627-1691 · Young, Thomas, 1773-1829 · Arago, F. (François), 1786-1853 · Light · Wave theory of light · Optical illusions · Gravitation · Vision
Internet Archive · UCL Library Services, University College London (UCL) · Public domain (published before 1931). Free to use for anything.
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