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Tending to disperse. Dispersive power (Opt.), the relative effect of a material in separating the different rays of light by refraction, as when the substance is formed into a prism. -- Dis*pers"ive*ness, n.

two separate lenses, a convex and concave, of substances having different refractive and dispersive powers, as crown and flint glass, with the curvatures so adjusted that the chromatic aberration produced by the one is corrected by other, and light emerges from the compound lens undecomposed. -- Achromatic prism. See…

of crown glass is corrected by a smaller concave lens, or combination of lenses, of high dispersive power, placed at a distance in the narrower part of the converging cone of rays, usually near the middle of the tube.

or tableware, and for optical instruments, as prisms, its density giving a high degree of dispersive power; -- so called, because formerly the silica was obtained from pulverized flints. Called also crystal glass. Cf. Glass.

ism composed usually of two prisms of different transparent substances which have unequal dispersive powers, as two different kinds of glass, especially flint glass and crown glass, the difference of dispersive power being compensated by giving them different refracting angles, so that, when placed together so as to ha…