Part 298

Di`o*phan"tine (?), a. Originated or taught by Diophantus, the Greek writer on algebra.

Diophantine analysis (Alg.), that branch of indeterminate analysis which has for its object the discovery of rational values that satisfy given equations containing squares or cubes; as, for example, to find values of x and y which make x2 + y2 an exact square.

Di*op"side (?), n. [Gr. di- = di`s- twice + &?; a sight, fr. the root of &?; I shall see: cf. F. diopside.] (Min.) A crystallized variety of pyroxene, of a clear, grayish green color; mussite.

Di*op"tase (?), n. [Gr. &?; = dia` through + &?; to see: cf. F. dioptase.] (Min.) A hydrous silicate of copper, occurring in emerald-green crystals.

{ Di*op"ter (?), ||Di*op"tra (?), } n. [L. dioptra, fr. Gr. &?;. See 2d Dioptric.] An optical instrument, invented by Hipparchus, for taking altitudes, leveling, etc.

||Di*op"tre (?), n. [F. See 2d Dioptric.] (Optics) A unit employed by oculists in numbering glasses according to the metric system; a refractive power equal to that of a glass whose principal focal distance is one meter.

Di*op"tric (?), a. (Optics) Of or pertaining to the dioptre, or to the metric system of numbering glasses. -- n. A dioptre. See Dioptre.

{ Di*op"tric (?), Di*op"tric*al (?), } a. [Gr. &?; belonging to the use of the &?;; &?; = dia` through + the root of &?; I shall see: cf. F. dioptrique.] Of or pertaining to dioptrics; assisting vision by means of the refraction of light; refractive; as, the dioptric system; a dioptric glass or telescope. "Dioptrical principles." Nichol.

Dioptric curve (Geom.), a Cartesian oval. See under Cartesian.

Di*op"trics (?), n. [Gr. &?; &?;: cf. F. dioptrique.] (Optics) 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.

Di*op"try (?), n. (Optics) A dioptre.

Di`o*ra"ma (?), n. [Gr. &?; to see through; &?; = dia` through + &?; to see; cf. &?; that which is seen, a sight: cf. F. diorama. Cf. Panorama.] 1. A mode of scenic representation, invented by Daguerre and Bouton, in which a painting is seen from a distance through a large opening. By a combination of transparent and opaque painting, and of transmitted and reflected light, and by contrivances such as screens and shutters, much diversity of scenic effect is produced.

2. A building used for such an exhibition.

Di`o*ram"ic (?), a. Pertaining to a diorama.

Di"o*rism (?), n. [Gr. &?;, fr. &?; to distinguish; &?; = dia` through + &?; to divide from, fr. &?; a boundary.] Definition; logical direction. [Obs.] Dr. H. More.

Di`o*ris"tic (?), a. [Gr. &?;.] Distinguishing; distinctive; defining. [R.] -- Di`o*ris"tic*al*ly (#), adv. [R.] Dr. H. More.

Di"o*rite (?), n. [Cf. F. diorite. See Diorism.] (Min.) An igneous, crystalline in structure, consisting essentially of a triclinic feldspar and hornblende. It includes part of what was called greenstone.

Di`o*rit"ic (?), a. Containing diorite.

Di`or*thot"ic (?), a. [Gr. &?;; &?; = &?; + &?; to set straight.] Relating to the correcting or straightening out of something; corrective.

||Di`os*co"re*a (?), n. [NL. Named after Dioscorides the Greek physician.] (Bot.) A genus of plants. See Yam.

||Di*o"ta (?), n. [L., fr. Gr. &?; two- handled; di- = di`s- twice + &?;, &?;, ear, handle.] (Rom. Antiq.) A vase or drinking cup having two handles or ears.

Di*ox"ide (?; 104), n. [Pref. di- + oxide.] (Chem.) (a) An oxide containing two atoms of oxygen in each molecule; binoxide. (b) An oxide containing but one atom or equivalent of oxygen to two of a metal; a suboxide. [Obs.]

Carbon dioxide. See Carbonic acid, under Carbonic.

Di`ox*in"dol (?), n. [Pref. di- + oxygen + indol.] (Chem.) A white, crystalline, nitrogenous substance obtained by the reduction of isatin. It is a member of the indol series; -- hence its name.

Dip (?), v. t. [imp. & p. p. Dipped (?) or Dipt (&?;); p. pr. & vb. n. Dipping.] [OE. dippen, duppen, AS. dyppan; akin to Dan. dyppe, Sw. doppa, and to AS. d&?;pan to baptize, OS. d&?;pian, D. doopen, G. taufen, Sw. döpa, Goth. daupjan, Lith. dubus deep, hollow, OSlav. dupl&?; hollow, and to E. dive. Cf. Deep, Dive.] 1. To plunge or immerse; especially, to put for a moment into a liquid; to insert into a fluid and withdraw again.

The priest shall dip his finger in the blood.

Lev. iv. 6.

Pope.