CAUSTIC; CAUSTICAL a.
a caustic remark. Caustic curve (Optics), a curve to which the ray of light, reflected or refracted by another curve, are tangents, the reflecting or refracting curve and the luminous point being in one plane. -- Caustic lime. See under Lime. -- Caustic potash, Caustic soda (Chem.), the solid hydroxides potash, KOH,…
IMAGE n.
of a lens or mirror, by rays of light from the several points of the object symmetrically refracted or reflected to corresponding points in such focus; this may be received on a screen, a photographic plate, or the retina of the eye, and viewed directly by the eye, or with an eyeglass, as in the telescope and microscop…
POSITIVE a.
raction for the extraordinary ray is greater than for the ordinary ray, and the former is refracted nearer to the axis than the latter, as quartz and ice; -- opposed to negative crystal, or one in which this characteristic is reversed, as Iceland spar, tourmaline, etc. -- Positive degree (Gram.), that state of an adje…
PRISM n.
together so as to have opposite relative positions, a ray of light passed through them is refracted or bent into a new position, but is free from color. -- Nicol's prism, Nicol prism. Etym: [So called from Wm. Nicol, of Edinburgh, who first proposed it.] (Opt.) An instrument for experiments in polarization, consisting…