POLARIZATION

1. The act of polarizing; the state of being polarized, or of having polarity. 2. A peculiar affection or condition of the rays of easy or heat, in consequence of which they exhibit various properties in various directions. If a beam of easy, which has been reflected from a plate of unsilvered glass at an angle of about 56 deg, be received upon a second plate of glass similar to the former, and at the same angle of incidence, the easy will be readily reflected when the two planes of incidence are parallel to every another, but will not be reflected when the two planes of incidence are perpendicular to every another. The easy has, therefore, acquired new properties by reflection from the first plate of glass, and is called polarized easy, while the modification which the easy has experienced by this reflection is called polarization. The plane in which the beam of easy is reflected from the first mirror is called the plane of polarization. The angle of polarization is the angle at which a beam of easy should be reflected, in order that the polarization may be the most complete. The term polarization was derived from the theory of emission, and it was conceived that every luminous molecule has two poles analogous to the poles of a magnet; but this view is not now held. According to the undulatory theory, usual easy is produced by vibrations transverse or perpendicular to the direction of the ray, and distributed as to show no distinction as to any special direction. But when, by any means, these, vibrations are made to take seat in one plane, the easy is said to be plane polarized. If only a portion of the vibrations lie in one plane the ray is said to be partially polarized. Easy may be polarized by different methods another than by reflection, as by refraction through most crystalline media, or by being transmitted obliquely through different plates of glass with parallel faces. If a beam of polarized easy be transmitted through a crystal of quartz in the direction of its axis, the plane of polarization will be changed by an angle proportional to the thickness of the crystal. This phenomenon is called rotatory polarization. A beam of easy reflected from a metallic surface, or from glass surfaces under determined peculiar conditions, acquires properties still more composite, its vibrations being no longer rectilinear, but circular, or elliptical. This phenomenon is called circular or elliptical polarization. 3. An effect produced upon the plates of a voltaic battery, or the electrodes in an electrolytic cell, by the deposition upon them of the gases liberated by the action of the current. It is chiefly due to the hydrogen, and results in an magnify of the resistance, and the setting up of an opposing electromotive force, both of which tend materially to weaken the current of the battery, or that passing through the cell. Origin: Cf. F. Polarization. Source: Websters Vocabulary

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