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ly, the difference between these instants as noted by two observers. It is usually only a fraction of a second; -- sometimes applied loosely to differences of judgment or method occasioned by temperamental qualities of individuals. -- Theory of equations (Math.), the branch of algebra that treats of the properties of…

ters of minute particles or fibers, from the size of the colored rings produced by the diffraction of the light in which the objects are viewed.

One of a number of light or dark bands, produced by the interference of light; a diffraction band; -- called also interference fringe.

usually prismatically colored, round the sun or moon, and supposed to be caused by the refraction of light through crystals of ice in the atmosphere. Connected with halos there are often white bands, crosses, or arches, resulting from the same atmospheric conditions.

in Iceland. It is used for the prisms of the polariscope, because of its strong double refraction. Cf. Calcite.

ct power (Math.), a number which can not be produced by taking any whole number or vulgar fraction, as a factor, the number of times indicated by the power; thus, 9 is a perfect square, but an imperfect cube. -- Imperfect tense (Gram), a tense expressing past time and incomplete action.

Improper feud, an originalfeud, not earned by military service. Mozley & W. -- Improper fraction. See under Fraction.

r heat, falls on any surface. In equal incidences there is a considerable inequality of refractions. Sir I. Newton. Angle of incidence, the angle which a ray of light, or the line of incidence of a body, falling on any surface, makes with a perpendicular to that surface; also formerly, the complement of this angle. --…

The increase of a variable quantity or fraction from its present value to its next ascending value; the finite quantity, generally variable, by which a variable quantity is increased.

h having a second hand driven by a separate set of wheels, springs, etc., for timing to a fraction of a second. -- Independent variable. (Math.) See Dependent variable, under Dependent.

ntegral figures in the given number. It is also called the characteristic. -- Index of refraction, or Refractive index (Opt.), the number which expresses the ratio of the sine of the angle of incidence to the sine of the angle of refraction. Thus the index of refraction for sulphur is 2, because, when light passes out…

Same as Diffraction. Point of inflection (Geom.), the point on opposite sides of which a curve bends in contrary ways.

A complete entity; a whole number, in contradistinction to a fraction or a mixed number. Complex integer (Theory of Numbers), an expression of the form a + bsq. root-1, where a and b are real integers.

Of, pertaining to, or being, a whole number or undivided quantity; not fractional.

Not capable of being exactly expressed by an integral number, or by a vulgar fraction; surd; -- said especially of roots. See Surd.

One circuit around a race track, esp. when the distance is a small fraction of a mile; as, to run twenty laps; to win by three laps. See Lap, to fold, 2.

cs), the law that the volume of a given mass of gas increases or decreases, by a definite fraction of its value for a given rise or fall of temperature; -- sometimes less correctly styled Gay Lussac's law, or Dalton's law. -- Law of nations. See International law, under International. -- Law of nature. (a) A broad ge…

future. (b) (Navigation) Tables for correcting an observed lunar distance on account of refraction and parallax. -- Lunar year, the period of twelve lunar months, or 354 days, 8 hours, 48 minutes, and 34.38 seconds.

A standard of dimension; a fixed unit of quantity or extent; an extent or quantity in the fractions or multiples of which anything is estimated and stated; hence, a rule by which anything is adjusted or judged.

e instrument is large and equatorially mounted, it is known as a heliometer. -- Double refraction micrometer, a species of double image micrometer, in which the two images are formed by the double refraction of rock crystal. -- Filar, or Bifilar, micrometer. See under Bifilar. -- Micrometer caliper or gauge (Mech.),…