reformIst

[Eng. reform; -ist.] 1. One who belongs to the reformed religion; a protestant. "We had a visible conspicuous church, to whom all other reformists gave the upper hand."- Howell : Letters, bk. iv., let. 36. 2. One who promotes or favors political reform; fracted ray takes the direction Cd. In the first place, the refracted ray will be found to be in the same plane as the inw cident ray. In the second place, if the medium below ww be the denser, the refracted ray will be bent toward the perpendicular, and the reverse in the con IMG:content-0361.png:[blocks in formation] refractive law. Draw Ds and ds normal to the perpendicular, then the lines Ds and ds will represent geometrically the sines of the arcs A Dand d B, and if the radius C A be unity, the numbers expre ings Dand ds will be the sines of the angles. The sines D will have a certain ratio to the sineds. And now if any other incident ray, E C, be taken, its sine found in the same way will be found to bear the same ratio to the sine of the refracted ray. This ratio of the sines is therefore invariable for all incidences for the same homogeneous substance. Such ratio is called its refractive index. And it will be readily seen how, the index of any substance-as some kind of optical gla -being once found by some simple experiment, the course of every refracted ray incident at any angle on the curved surface of a lens can be foreseen, and thus its focus and other properties calculated, or the curves calculated for a given focns, which is simply the point to which refracted rays converge. (1) Astronomical, atmospheric, or celestial re fraction: Astron., .: The alteration of the direction of a luminous ray proceeding from a heavenly body to the eye of a spectator on the earth. It is caused by the pa age of the ray from space or the rarer air high in the atmosphere to the denser medium near the surface of the earth. It produces the greatest effect when the heavenly body is on the horizon, and is non-existent when it is in the zenith. It makes a heavenly body appear higher than it is, or even visible before it has really risen. Allowance must be made for refraction in all observations of altitude. The amount of refraction at a certain elevation above the horizon, for a certain temperature of the air, and a certain height of the barometer, may be approximately determined, but minute variations in it make the corrected places of the stars occasionally wrong by a second or more. ( Ball .) (2) Axis of double refraction: [Axis.] (3) Axis of refraction: [AXIS.] (4) Conical refraction : Optics: The refraction of a ray of light into a number of other rays forming a hollow cone. It arises when a ray of light pa es through biaxial crystals [ Polarization of Light ) in a particular direction, nearly coinciding with the optic axis. When the ray, leaving the crystal, forms a cone with the apex at the point of emergence, it is called external conical refraction; when the cone is formed by the ray on entering the crystal, and it emerges in a hollow cylinder, it is called internal conical refraction. It was first reasoned out by Sir William R. Hamilton, and subsequently demonstrated experimentally by Lloyd. (5) Double refraction : Optics: Many crystals are not homogeneous, but have different properties of elasticity, ., in dif. ferent directions. The effect of such a constitution is, that unle a ray of light enters the crystal in some particular directions, it is not merely refracted in the manner described under Refraction, but divided into two rays. In this case the refracted ray or rays are not always in the same plane as the incident ray. [ Polarization of Light .] (6) Index of refraction : [INDEX, 8., (4).] (1) Plane of refraction : The plane pa ing through the normal or perpendicular to the refracting surface, at the point of incidence and the refracted ray. (8) Point of refraction : [POINT, 8., 14.] (9) Refraction of altitude and declination , of ascension and descension , of latitude and longitude : The change in the altitude, declination, ., of a heavenly body, due to the effect of atmospheric refraction. (10) Refraction of sound: Physics: The change of direction which takes place when waves of sound pa from one medium to another. It follows the same law as light. It was discovered by Sondhau . (11) Terrestrial refraction : Optics: Refraction making terrestrial bodies such as distant buildings or hills, ., look higher than they really are. The principle is the same as in Astronomical Refraction. [(1).] rě-frăc-tive, adj . [Fr. réfract if .] [REFRACT.] Pertaining or relating to refraction; tending or serving to refract or deflect from a direct course. "Transmitted through a variety of refractive surfaces." -Bp. Horsley: Sermons, vol. ii., ser. 17. refractive-index, subst. The same as Index of Refraction. [INDEX, 8., refractive-power, s. (4).] Optics: A comparative term practically synonymous with optical density, and specifying the degree in which a body refracts light (or heat, .). [REFRACTION.]