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The history of spectroscopy began in the 17th century. Advances in optics, specifically prisms, enabled systematic observations of the solar spectrum. Isaac Newton first applied the word ''spectrum'' to describe the rainbow of colors that combine to form white light. During the early 1800s, Joseph von Fraunhofer made experimental advances with dispersive spectrometers that enabled spectroscopy to become a more precise and quantitative scientific technique. Since then, spectroscopy has played and continues to play a significant role in chemistry, physics and astronomy. ==Origins and experimental development== The Romans were already familiar with the ability of a prism to generate a rainbow of colors. Newton is traditionally regarded as the founder of spectroscopy, but he was not the first scientist who studied and reported on the solar spectrum. The works of Athanasius Kircher (1646), Jan Marek Marci (1648), Robert Boyle (1664), and Francesco Maria Grimaldi (1665), predate Newton's optics experiments (1666–1672). Newton published his experiments and theoretical explanations of dispersion of light in his 'Opticks'. His experiments demonstrated that white light could be split up into component colors by means of a prism and that these components could be recombined to generate white light. He demonstrated that the prism is not imparting or creating the colors but rather separating constituent parts of the white light.〔(【引用サイトリンク】 url = http://web.mit.edu/spectroscopy/history/history-classical.html )〕 Newton's corpuscular theory of light was gradually succeeded by the wave theory. It was not until the 19th century that the quantitative measurement of dispersed light was recognized and standardized. As with many subsequent spectroscopy experiments, Newton's sources of white light included flames, the sun and stars. Subsequent experiments with prisms provided the first indications that spectra were associated uniquely with chemical constituents. Scientists observed the emission of distinct patterns of color when salts were added to alcohol flames.〔Brand, p. 58〕 Joseph von Fraunhofer made a significant experimental leap forward by replacing a prism with a diffraction grating as the source of wavelength dispersion. Fraunhofer built off the theories of light interference developed by Thomas Young, François Arago and Augustin-Jean Fresnel. He conducted his own experiments to demonstrate the effect of passing light through a single rectangular slit, two slits, and so forth, eventually developing a means of closely spacing thousands of slits to form a diffraction grating. The interference achieved by a diffraction grating both improves the spectral resolution over a prism and allows for the dispersed wavelengths to be quantified. Fraunhofer's establishment of a quantified wavelength scale paved the way for matching spectra observed in multiple laboratories, from multiple sources (flames and the sun) and with different instruments. Fraunhofer made and published systematic observations of the solar spectrum, and the dark bands he observed and specified the wavelengths of are still known as Fraunhofer lines.〔Brand, pp. 37-42〕 Throughout the early 1800s, a number of scientists pushed the techniques and understanding of spectroscopy forward.〔(【引用サイトリンク】 url = http://www.spectroscopyonline.com/spectroscopy/article/articleDetail.jsp?id=381944 )〕 In the 1820s both John Herschel and William H. F. Talbot made systematic observations of salts using flame spectroscopy.〔Brand, p. 59〕 In 1835, Charles Wheatstone reported that different metals could be easily distinguished by the different bright lines in the emission spectra of their sparks, thereby introducing an alternative mechanism to flame spectroscopy. In 1849, J. B. L. Foucault experimentally demonstrated that absorption and emission lines appearing at the same wavelength are both due to the same material, with the difference between the two originating from the temperature of the light source.〔Brand, pp. 60-62〕 In 1853, the Swedish physicist Anders Jonas Ångström presented observations and theories about gas spectra in his work: ''Optiska Undersökningar'' to the
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