Part 626

2. (Opt.) Of or pertaining to the spectrum; made by the spectrum; as, spectral colors; spectral analysis.

Spectral lemur. (Zoöl.) See Tarsius.

Spec"tral*ly, adv. In the form or manner of a specter.

Spec"tre (?), n. See Specter.

Spec`tro*log"ic*al (?), a. Of or pertaining to spectrology; as, spectrological studies or experiments. -- Spec`tro*log"ic*al*ly, adv.

Spec*trol"o*gy (?), n. [Spectrum + -logy.] (Chem.Phys.) The science of spectrum analysis in any or all of its relations and applications.

Spec*trom"e*ter (?), n. [Spectrum + -meter.] (Physics) A spectroscope fitted for measurements of the luminious spectra observed with it.

Spec`tro*pho*tom"e*ter (?), n. [Spectrum + photometer.] (Opt.) An instrument for measuring or comparing the intensites of the colors of the spectrum.

Spec"tro*scope (?), n. [Spectrum + -scope.] (Physics) An optical instrument for forming and examining spectra (as that of solar light, or those produced by flames in which different substances are volatilized), so as to determine, from the position of the spectral lines, the composition of the substance.

{ Spec`tro*scop"ic (?), Spec`tro*scop"ic*al (?) }, a. Of or pertaining to a spectroscope, or spectroscopy. -- Spec`tro*scop"ic*al*ly, adv.

Spec*tros"co*pist (? or ?), n. One who investigates by means of a spectroscope; one skilled in the use of the spectroscope.

Spec*tros"co*py (?), n. The use of the spectroscope; investigations made with the spectroscope.

Spec"trum (?), n.; pl. Spectra (#). [L. See Specter.] 1. An apparition; a specter. [Obs.]

2. (Opt.) (a) The several colored and other rays of which light is composed, separated by the refraction of a prism or other means, and observed or studied either as spread out on a screen, by direct vision, by photography, or otherwise. See Illust. of Light, and Spectroscope. (b) A luminous appearance, or an image seen after the eye has been exposed to an intense light or a strongly illuminated object. When the object is colored, the image appears of the complementary color, as a green image seen after viewing a red wafer lying on white paper. Called also ocular spectrum.

Absorption spectrum, the spectrum of light which has passed through a medium capable of absorbing a portion of the rays. It is characterized by dark spaces, bands, or lines. -- Chemical spectrum, a spectrum of rays considered solely with reference to their chemical effects, as in photography. These, in the usual photogrophic methods, have their maximum influence at and beyond the violet rays, but are not limited to this region. -- Chromatic spectrum, the visible colored rays of the solar spectrum, exhibiting the seven principal colors in their order, and covering the central and larger portion of the space of the whole spectrum. -- Continous spectrum, a spectrum not broken by bands or lines, but having the colors shaded into each other continously, as that from an incandescent solid or liquid, or a gas under high pressure. -- Diffraction spectrum, a spectrum produced by diffraction, as by a grating. -- Gaseous spectrum, the spectrum of an incandesoent gas or vapor, under moderate, or especially under very low, pressure. It is characterized by bright bands or lines. -- Normal spectrum, a representation of a spectrum arranged upon conventional plan adopted as standard, especially a spectrum in which the colors are spaced proportionally to their wave lengths, as when formed by a diffraction grating. -- Ocular spectrum. See Spectrum, 2 (b), above. -- Prismatic spectrum, a spectrum produced by means of a prism. -- Solar spectrum, the spectrum of solar light, especially as thrown upon a screen in a darkened room. It is characterized by numerous dark lines called Fraunhofer lines. -- Spectrum analysis, chemical analysis effected by comparison of the different relative positions and qualities of the fixed lines of spectra produced by flames in which different substances are burned or evaporated, each substance having its own characteristic system of lines. -- Thermal spectrum, a spectrum of rays considered solely with reference to their heating effect, especially of those rays which produce no luminous phenomena.

Spec"u*lar (?), a. [L. specularis (cf., from the same root, specula a lookout, watchtower): cf. F. spéculaire. See Speculum.] 1. Having the qualities of a speculum, or mirror; having a smooth, reflecting surface; as, a specular metal; a specular surface.

2. (Med.) Of or pertaining to a speculum; conducted with the aid of a speculum; as, a specular examination.

3. Assisting sight, as a lens or the like. [Obs.]

Thy specular orb Apply to well-dissected kernels; lo! In each observe the slender threads Of first-beginning trees.

J. Philips.

4. Affording view. [R.] "Look once more, ere we leave this specular mount." Milton.

Specular iron. (Min.) See Hematite.

Spec"u*late (?), v. i. [imp. & p. p. Speculated (?); p. pr. & vb. n. Speculating.] [L. speculatus, p. p. of speculari to spy out, observe, fr. specula a lookout, fr. specere to look. See Spy.] 1. To consider by turning a subject in the mind, and viewing it in its different aspects and relations; to meditate; to contemplate; to theorize; as, to speculate on questions in religion; to speculate on political events.

It is remarkable that persons who speculate the most boldly often conform with the most pefect quietude to the external regulations of society.

Hawthorne.

2. (Philos.) To view subjects from certain premises given or assumed, and infer conclusions respecting them a priori.

3. (Com.) To purchase with the expectation of a contingent advance in value, and a consequent sale at a profit; -- often, in a somewhat depreciative sense, of unsound or hazardous transactions; as, to speculate in coffee, in sugar, or in bank stock.

Spec"u*late, v. t. To consider attentively; as, to speculate the nature of a thing. [R.] Sir W. Hamilton.