Coblentz, William

Since 1905, when William W. Coblentz obtained the first infrared spectrum (1), vibrational spectroscopy has become an important analytical tool in research and in technical fields. In the late 1960s, infrared spectrometry was generally believed to be an instrumental technique of declining popularity that was gradually being superseded by nuclear magnetic resonance (NMR) and mass spectrometry (MS) for structural determinations and by gas and liquid chromatography for quantitative analysis. 

The discovery of the NIR spectrum was reported in 1800 by William Herschel (17, 19), yet the NIR spectrum did not appear as a potential analytical tool until the middle of the twentieth century (7, 52, 65). The contributions of the pioneers cannot be ignored. People like Coblentz (5), Ellis (9), Wulf and Liddel (68), and Collins (6) were among the first to study NIR spectroscopy. After 1950 and well into the 1960s, NIR spectrometry became even more popular with researchers like Kaye (25), Willis (66), Goddu (13), Wetzel (59), Wheeler (58), and Norris (44) who made contributions to both NIR spectroscopy and spectrometry. It was Norris who first demonstrated that NIR spectrometry could be calibrated with multiple linear regression. 

Development of a reliable method of measuring infrared spectra was an important subject of research in physics in the beginning of the twentieth century. William W. Coblentz (1873-1962) made a major contribution to the instrumentation of early infrared spectrometers and the compilation of the infrared spectra of many organic compounds in the period before 1930. At that time, alkali halide crystals were used as the prism for dispersing infrared radiation. 

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