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That branch of physical science which treats of the nature and properties of light, the laws of its modification by opaque and transparent bodies, and the phenomena of vision.

False optics. Spectator.

The art or process of exhibiting luminous images, especially those of external objects, in a darkened room, by arrangements of lenses or mirrors.

That part of optics which treats of the refraction of light; -- commonly called dioptrics. Encyc. Brit.

That part of optics which explants the properties and phenomena of reflected light, and particularly that which is reflected from mirrors or polished bodies; --- formerly caled anacamptics.

Severe; satirical; sharp; as, 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…

The science of colors; that part of optics which treats of the properties of colors.

ed by the action of cold water or air. See Illust. of Steam engine. Achromatic condenser (Optics), an achromatic lens used as a condenser. -- Bull's-eye condenser, or Bull's-eye (Optics), a lens of short focal distance used for concentrating rays of light. -- Injection condenser, a vessel in which steam is condensed…

parallel to the other. -- Conjugate focus (Opt.) See under Focus. -- Conjugate mirrors (Optics), two mirrors so placed that rays from the focus of one are received at the focus of the other, especially two concave mirrors so placed that rays proceeding from the principal focus of one and reflected in a parallel beam…

nt, the critical minute, on which every good work so much depends. South. Critical angle (Optics), that angle of incidence of a luminous ray at which it is wholly reflected, and no portion of it transmitted. The sine of this angle is the reciprocal of the refractive index of the medium. -- Critical philosophy, the met…

by him to a property of light which he called diffraction. Whewell. Diffraction grating. (Optics) See under Grating. -- Diffraction spectrum. (Optics) See under Spectrum.

The science of the refraction of light; that part of geometrical optics which treats of the laws of the refraction of light in passing from one medium into another, or through different mediums, as air, water, or glass, and esp. through different lenses; -- distinguished from catoptrics, which refers to reflected light…

An arrangement of a fleet in a wedge or Encyc. Dict. Echelon lens (Optics), a large lens constructed in several parts or layers, extending in a succession of annular rings beyond the central lens; - - used in lighthouses.

the retinal blood vessels projected in, not merely on, that membrane. -- Virtual image (Optics), a point or system of points, on one side of a mirror or lens, which, if it existed, would emit the system of rays which actually exists on the other side of the mirror or lens. Clerk Maxwell.

state of interfering, or of claiming a right to the same invention. Interference figures (Optics), the figures observed when certain sections of crystallized bodies are viewed in converging polarized light; thus, a section of a uniaxial crystal, cut normal to the vertical axis, shows a series of concentric colored ring…

The organ of sight; an eye. The difference is as great between The optics seeing, as the object seen. Pope.

Relating to the science of optics; as, optical works. Optic angle (Opt.), the angle included between the optic axes of the two eyes when directed to the same point; -- sometimes called binocular parallax. -- Optic axis. (Opt.) (a) A line drawn through the center of the eye perpendicular to its anterior and posterior s…

By optics or sight; with reference to optics. Optically active, Optically inactive (Chem. Physics), terms used of certain metameric substances which, while identical with each other in other respects, differ in this, viz., that they do or do not produce right-handed or left-handed circular polarization of light. -- Op…

One skilled in optics. [R.] A. Smith.

The science of light; -- a general term sometimes employed when optics is restricted to light as a producing vision. Knight.