spectroscopist

[English spectroscop (e); -ist. One who uses the spectroscope; one who is skilled in spectroscopy. spěc-tros-co-pỹ, 8. [Eng. spectroscop(e); -y.] That branch of science which is concerned with the use of the spectroscope and with spectral analysis. spectrum ( pl . *spěc-trămş, spěc-tra.), s. [Lat. an appearance, image, apparition, specter (q.v.).] *1. Ord. Lang .: A specter. "Lavater puts solitarine a main cause of such speo trums or apparitions." -Burton : Anat. of Melancholy, pt. iii. § 4, p. 2. liquids heated to incandescence-as the particles of soot in a candle-flame-always yield an unbroken band of colors shading into one another; this is called a continuous spectrum. Incandescent gases generally yield lines or bands only, and this is a line or banded spectrum. When portions of what would have been a continuous spectrum are intercepted or cut out by an intervening medium, this is called an absorption spectrum. Besides the waves of such a length as cause visual effects, there are many more beyond th red at one end of the spectrum and the violet at the other, which produce powerful chemical and heating effects. This portion is sometimes called the Invisible Spectrum, sometimes described as the Ultra-red or Ultraviolet spectrum. Its length greatly exceeds that of the visible spectrum, and it is found to comprise lines and bands precisely analogous to those occur ring in the luminous portion. [SPECTRUM-ANALYSIS.] spectrum-analysis, s . Physics and Chemistry : The determination of the chemical composition, the physical condition, or both, of any body by the Spectrum (q. v.) of the light which it emits or suffers to pa through it, under certain conditions. For such determinations an instrument is used called the Spectroscope (q. v.), which employs the light pa ing through a very narrow slit, and, by using more prisms than one, disperses or separates the colors a great deal more than one prism alone can do. The human eye is totally unable to judge of the real component colors of any light presented to it; not only does a mixture of all colors appear white, but so do many simple pairs of colors; and, similarly, two apparently similar shades of color, may be quite differently constituted, the one being perhaps a pure color, while the other is really a compound. The prism never errs, but rigidly sorts out any light presented to it under all the separate wave-lengths elements; and thus was proved the fact that the incandescent photosphere of the sun is surrounded by a highly-heated, but still by comparison cooler, atmosphere containing hydrogen, sodium, iron, and many other substances. Subsequently, by suitable disc. The chemistry and condition of the stars spěc-u-lăte, v. i. & t. [Lat. speculatus , pa. par. were rapidly studied in the same way, with the of speculor =to behold, from specula =a watch- result of discovering very interesting resemblances, and in many cases still more interesting and marked differences between their condition and that of the sun. In this way, for instance, when a great increase in the brilliancy of the variable star Tau Corone was observed in May. 1886, the spectro- scope showed its usual absorption spectrum to be cro ed by a few bright lines, and thus the phenom- enon was clearly traced to some almost inconceiv able outburst of glowing hydrogen, as was also the "new star" which appeared in Cygnus in 1876. In another star there is an abundant quantity of the metal tellurium, which cannot be traced in our sun, and is only present in exceedingly small quan- Spectrum analysis has finally led to a theory or speculation of capital importance, concerning the so-called "elements." The spectra of compounds are as characteristic as those of what are called elements; but as the temperature of the luminous vapor is increased, this spectrum breaks up, as it were, into the lines of the elements themselves. Where the vapor is known to be "di ociated," as it is termed, at a certain temperature, there is sim ultaneously a marked and sudden change in its spectrum. Now it is found that even at tempera- tures produced in our laboratories the spectra of the so-called elements themselves go through anal- ogous changes as the temperature is raised, giving apparently similar reason to believe that they then break up into still simpler elements. In the far greater heat of the sun's chromosphere there is much more evidence of this proce going on, and there is one strong line in particular which has never been identified with any element known on earth. It further appears, that unle we are to suppose an amount of impurity hardly po ible, different elements are capable at certain high temperatures of giving rise to certain coincident lines; and from these and other collated facts, such as an ascertained relation between the atomic weight of an element and the position of its lines in the spectrum, it is now held to be probable that the so-called elements are themselves com- pounds, which at a certain temperature are broken up into much fewer elements, or po ibly into one. This conclusion is one of the latest results of spec trum analysis. laris pertaining to a mirror, from speculum = a spěc-u-lar, a . [Fr. spéculaire , from Lat. specu- I. Ordinary Language : 1. Having the qualities of a mirror or looking. gla ; having a smooth reflecting surface. "The object in our case served for a specular body, to reflect that color to the eye."- Boyle : Works, i. 693. erties. *2. A isting the sight by means of optical prop- "Thy specular orb Apply to well-di ected kernels: lo! In each observe the slender threads Of first-beginning trees." -Philips: Cider, i. *3. Affording a wide view or prospect. "Look once more ere we leave this specular mount." Milton: P. R. , iv. 236. II. Min .: Presenting a smooth and brilliant sur- face, which reflects light like a mirror. Hematite (q. v.). Min.: A bright shining crystallized variety of spěc-u-lär-i-a, s. [Lat. specular is =pertaining to a mirror; speculum a mirror. Named on ac- count of the brightne of the flowers when in sun- shine.] IMG:content-1795.png:[blocks in formation] IMG:content-1796.png:[blocks in formation] "My speculative and officed instruments." Shakesp.: Othello, i. 3. 5. Pertaining to or given to speculation in trade; engaged in speculation; speculating. "The speculative merchant exercises no one regular, established, or well-known branch of busine ."- Smith : Wealth of Nations , bk. i., ch. x. 6. Of the nature of a speculation in trade; hazardous, risky; as, a speculative busine or transaction. spěc-u-la-tive-lý, adv . [ Eng.speculative ; -ly .] 1. In a speculative manner; with speculation, theory, contemplation, or meditation; contemplatively. "I have discoursed more speculatively than 'tis fit in a book that is designed for common use and edification."Scott: Christian Life . (Pref.) 2. Ideally, theoretically; in theory only, not in practice; not practically. "For conscience signifies, speculatively , the judgment we pa of things upon whatever principles we chance to have." - War burton: Comment. on Pope's E ay on Man . 3. In the way of speculation in trade. *spěc-u-la-tive-ne , s . [English speculative ; ne .] The quality or state of being speculative; the state of consisting in speculation only.