polaryt (poʻlari)

lar.] [ All which acquire a magnetical polary condition, and, being suspended, convert their lower extream unto the North; with the same attracting the Southern point of the needle. Sir T. Browne , Vulg. Err., ii. 2. pol a touche (pol-ä-tösh'), n. [F.] The small flying-squirrel of Europe and Asia, a species of the genus Sciuropterus. Also pal a touche. polaynet, n. Same as poulaine. poldavist, n. Same as poledary. polder (pol'dėr), n. [D.] A boggy or marshy soil; a mora ; specifically, a tract of marshy land in the Netherlands, Flanders, and northern Germany, which has been reclaimed and brought under cultivation. polder-land (pol'dėr-land), n. In the Netherlands and adjoining regions, marshy land which has been reclaimed and brought under cultivation. Thus the privileges of the Abbey of St. Pierre of Ghent of about the year 830 mention the existence of a partner ship of fifty members for the working of some polder - land. W. K. Sullivan , Introd. to O'Curry's Anc. Irish, p. ccxii. larized. - Polarization of a dielectric, or dielectric polarization, a phrase introduced by Faraday to describe the condition of a non-conductor or dielectric, as he con- ceived it, when in a state of strain under the action of two adjacent charges of positive and negative electricity, as, for example, in the condenser. - Polarization of light, a change produced in light by reflection from or trans- mi ion through certain media by which the transverse vibrations of the ether (see light1 ) are limited to a single plane, while in a ray of ordinary light these vibrations take place indifferently in any plane about the line of propagation. Polarization may be effected (1) by reflection dron . from a surface of gla , water, or similar substance, and it is most complete if the angle of incidence has a certain value, depending upon the substance, called the angle of polarization (for gla 54°), the tangent of this angle be- ing equal to the refractive index of the given substance (Brewster's law); (2) by transmi ion through a series of transparent plates of gla placed in parallel position at the proper angle to the incident ray; and (3) by double refraction in any transparent anisotropic crystal (see re- fraction ). In the last case the two rays into which the incident ray is separated upon refraction are polarized in planes at right angles to each other, as, for example, in transparent calcite (Iceland spar), in which this double refraction is most marked. A prism of Iceland spar may be prepared in such a way that one of the two refract- ed rays suffers total reflection and is extinguished; the other ray, which pa es through, is polarized, its vibra- tions taking place in the direction of the shorter diagonal of the cro -section. Such a prism is called a Nicol prism , =