Talbot, William

A. D. Spigelman, C. B. Williams, I. C. Talbot, P. Domizio and R. K. Phillips, Upper gastro-intestinal cancer in patients with familial adenomatous polyposis, Lancet, 1989, 2(8666), 783. 

William Henry Fox Talbot, 1800-1877. English antiquarian, physicist, and pioneer in optics and photography. One of the first to decipher the Assyrian inscriptions at Nineveh. In 1839 he made negative prints on silver chloride paper, and two years later he invented the calotype process for... 

Page, Talbot. 1981. A Framework for Unreasonable Risk in the Toxic Substances Control Act (TSCA). In Management of Assessed Risk for Carcinogens. Edited by William J. Nicholson. New York New York Academy of Sciences. 

Hallund J, Bugel S, Tholstrup T, Ferrari M, Talbot D, Hall WL, Reimann M, Williams CM, Wiinberg N. 2006. Soya isoflavone-enriched cereal bars affect markers of endothelial function in postmenopausal women. Br J Nutr 95 1120-1126. 

Line spectra were first observed by J. von Fraunhofer, D. Brewster, and J. F. W. Herschel in the 1820s.180 In the ensuing decades a considerable amount of work was done on spectral phenomena prior to the demonstration by Bunsen and Kirchhoff in 1859 that line spectra could be used for qualitative chemical analysis. Accounts have appeared of the development of the spectroscope both prior and post Bunsen and Kirchhoff.181-183 Significant observations were undoubtedly made prior to 1860 by Stokes, Stewart, Fox Talbot, and others. The priority claims of Stokes, who recorded his ideas in some private letters to William Thomson, have been examined.184 The work of Bunsen and Kirchhoff did not owe a great deal to that of their predecessors, with the exception of the demonstration by W. Swan in 1856 that the almost omnipresent yellow line that coincided with Fraunhofer s dark solar D line was due to contamination by minute quantities of sodium salts.185 186 Platinum played an important role in the early development of spectroscopy. The metal was widely used to support the material in the flame, since it did not colour the flame itself. Bunsen ensured the purity of all his samples for spectrum analysis by recrystallization (sometimes up to fourteen times) in platinum vessels, thereby preventing contamination by minute quantities of salts that could be leached from glass vessels.187 Sharply contrasting views have been expressed about the failure of chemists prior to Bunsen to exploit spectroscopy.188-190... 

By this time, scientists were studying light from as many sources as they could conjure. In 1822, the Scotsman David Brewster (1781-1868) invented a device that, by means of a flame, vaporized small amounts of material. The light from this vaporized material could then be smdied. He added 1,600 new spectral lines to those discovered by Fraunhofer and other investigators. During the same year, 1822, John Herschel (1792-1871), William Herschel s son, vaporized various metallic salts and established that the light from the flames could be used to detect the presence of these metals in very small samples. A few years later, William Talbot (1800-1877) showed that the spectrum of each of the chemical elements was unique and that it was possible to identify the chemical elements from their spectra. 

This calotype of a leaf was taken by the inventor of the process, William Henry Fox Talbot, in 1844. In its earliest form, the photosensitive paper was created by coaitfhg thP paper with a sodium chloride solution, allowing the paper to dry, and then applyy ihg a second coat of silver nitrate, which produced a film of silver chloride, the lealf was then placed on the paper and exposed to light. The silver chloride in the paper was produced by the chemical equilibrium Ag+ + Cr AgCI[s), which is driven by the activities of reactants and products. 

J. A. Scarrow G. Schiemann Lloyd A. Smith John M. Snell L. F. Somerville William F. Talbot S. W. Tompkins Joseph T. Walker Richard Weiss W. Winkelmuller Bruno H. WojctK... 

Figure 2.7 Portrait of William Henry Fox Talbot. (Published with permission from the Deutsches Museum, Munich.)...

In the 1820s, David Brewster (1781-1868), Sir John Herschel (1792-1871), and William Henry Fox Talbot performed similar types of experiments on the absorption of light to those by Fraunhofer. Independently, these researchers made the observation that flame spectra obtained by burning compounds of different compositions varied in systematic ways. These three researchers all produced line spectra, which they tried to relate to the dark lines observed by Fraunhofer... 

Through further optical and chemical processes that need not be described here, a realistic portrayal of the scene is eventually obtained. The process is termed photography ( light-writing ). A number of men contributed to the new technique, including the French physicist Joseph Nicephore Niepce (1765-1833), the French artist Louis Jacques Mande Daguerre (1789-1851), and the English inventor William Henry Fox Talbot (1800-77). 

First negatives in photography (William Henry Fox Talbot) Talbot, an English polymath, invents the calotype process, which produces the first photographic negative. 

Millet DB, Jacob DJ, Custer TG, de Gouw JA, Goldstein AH, Karl T, Singh HB, Sive BC, Talbot RW, Wameke C, Williams J (2008) New constraints on terrestrial and oceanic sources of atmospheric methanol. Atmos Chem Phys 8 6887... 

Hall, W.L., Vafeiadou, K., Hallund, J., Bugel, S., Koebnick, C., Reimann, M., Ferrari, M., Branca, F., Talbot, D., Dadd, T., Nilsson, M., Dahlman-Wright, K., Gustafsson, J.A., Minihane, A.M., and Williams, C.M. 2005. Soy-isoflavone-enriched foods and inflammatory biomarkers of cardiovascular disease risk in postmenopausal women interactions with genotype and equol production. Am J Clin Nutr 82, 1260-1268 quiz 1365-1266. 

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