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Spectrometers
Published in Daniel Malacara-Hernández, Brian J. Thompson, Fundamentals and Basic Optical Instruments, 2017
The first observation of spectral lines was made by Thomas Melville in 1752 [1]. He used a prism and small aperture to observe the different spectra produced by sal ammoniac, alum potash, and other substances. Wollaston (1766–1828) observed the spectrum of the blue base of a candle flame and William Swan saw what are now called the Swan ands in 1856. The first use of the spectrometer as a wave analyzer must belong to Fraunhofer. While measuring the refractive indices of various glasses in about 1815 (independent of the works cited above), he observed the sodium doublet. He then proceeded to observe the Fraunhofer lines of the sun, first with a slit and prism and then with a slit and a diffraction grating. This work was followed in 1835 by Herschel and many other luminaries of physics: Talbot, Foucault, Daguerre, Becquerel, Draper, Angstrom, Bohr, Kirchhoff, Bunsen, Stewart …. The critical step of identifying the molecular and atomic structure was the accomplishment of Bunsen and Kirchhoff, although others were involved, including Miller, Stokes, and Kelvin.
Bonnington chemical works (1822–1878): pioneer coal tar company
Published in The International Journal for the History of Engineering & Technology, 2020
Bonnington was continuing to produce refined naphtha, pitch oil, pitch, sal ammoniac, ammonium sulphate, and antichlor. Ronalds was also mixing copper salt with hydrosulphuret of ammonia [ammonium hydrosulphide] from the ammoniacal liquor, precipitating sulphuret of copper [copper sulphide]; this was used to make the marine antifouling paint. Several new products were itemised as well. The coke oil and coke samples indicate that additional distillations were now conducted to collect a heavy oil fraction from the tar. He had also further distilled the first fraction to isolate benzole [benzene]. Benzene had been discovered in coal tar the previous decade and in 1848 Charles Mansfield patented a method of fractional distillation to separate it and other chemical compounds at scale.66