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ion, sphere, cube, etc., and terminated by the opposite boundaries; a straight line which bisects a system of parallel chords drawn in a curve.

meter; diametrical. Diametral curve, Diametral surface (Geom.), any line or surface which bisects a system of parallel chords drawn in a curve or surface. -- Diametral planes (Crystal.), planes in which two of the axes lie.

To cut into two parts; to part into two divisions; to divide into pairs; to bisect. [R.] The apostolical benediction dichotomizes all good things into grace and peace. Bp. Hall.

That phase of the moon in which it appears bisected, or shows only half its disk, as at the quadratures.

ilateral shell (Zoöl.), one in which a transverse line drawn through the apex of the umbo bisects the valve, or divides it into two equal and symmetrical parts. -- Mutually equilateral, applied to two figures, when every side of the one has its equal among the sides of the other.

oup of birds characterized by having long slender bills, as the sandpipers, curlews, and ibises. It is now regarded as an artificial division.

ed also, especially by European writers, mean error. -- Mean line. (Crystallog.) Same as Bisectrix. -- Mean noon, noon as determined by mean time. -- Mean proportional (between two numbers) (Math.), the square root of their product. -- Mean sun, a fictitious sun supposed to move uniformly in the equator so as to be…

in which two images of an object are formed in the field, usually by the two halves of a bisected lens which are movable along their line of section by a screw, and distances are determined by the number of screw revolutions necessary to bring the points to be measured into optical coincidence. When the two images are…

ngle of a miter. -- Miter joint, a joint formed by pieces matched and united upon a line bisecting the angle of junction, as by the beveled ends of two pieces of molding or brass rule, etc. The term is used especially when the pieces form a right angle. See Miter, 2. -- Miter shell (Zoöl.), any one of numerous specie…

of a quadric (Geom.), three planes each of which is at right angles to the other two, and bisects all chords of the quadric perpendicular to the plane, as in an ellipsoid. -- Principal point (Persp.), the projection of the point of sight upon the plane of projection. -- Principal ray (Persp.), the line drawn through…

nt for experiments in polarization, consisting of a rhomb of Iceland spar, which has been bisected obliquely at a certain angle, and the two parts again joined with transparent cement, so that the ordinary image produced by double refraction is thrown out of the field by total reflection from the internal cemented surf…

Anything which is required to be done; as, in geometry, to bisect a line, to draw a perpendicular; or, in algebra, to find an unknown quantity.

ght; a biaxial crystal is similarly designated when the same relation holds for the acute bisectrix. -- Index of refraction. See under Index. -- Refraction circle (Opt.), an instrument provided with a graduated circle for the measurement of refraction. -- Refraction of latitude, longitude, declination, right ascensi…

A half column; a column bisected longitudinally, or along its axis.

A genus of wading birds comprising the wood ibises. Tantalus's cup (Physics), a philosophical toy, consisting of a cup, within which is the figure of a man, and within the figure a siphon, the longer arm of which passes down through the bottom of the cup, and allows the escape of any liquid that may be poured in, when…

animals in which the sexes are in separate individuals; dioecious; -- distinguished from bisexual, or hermaphrodite. See Dioecious.