Page:Encyclopædia Britannica, Ninth Edition, v. 18.djvu/874

 838 PHOTOGRAPHY H h c r i o CB* Washed 3AgI + AgCl on D. paper, ferrous citro-oxal- ate developer 3AgI-fAgCl in gelatin, de- D. veloped ferrous oxalate Agl+AgCl in gelatin, de- D. veloped ferrous oxalate AgI + 3AgCl on paper, washed P. l + SAgCl+AgXOa, wet .. P. AgI+3AgCl in gelatin, or D. on paper, ferrous citro- oxalate or acid developer Agl + 3AgCl + AgXO 3) acid D. developer AgBr, exposed to light, P. treated with I, exposed, to also spectrum. D. of uranium, which shows, too, absorption-bands in the green blue, is affected more where these occur than in any other portion of the spectrum. It would be going beyond our province to do more than enumerate the other metallic com pounds which are amenable to chemical change by the impact of radiation ; suffice it to say that some salts of mercury, gold, copper, lead, manganese, molybdenum, platinum, vanadium, are all affected, but in a less degree than those which Ave have discussed. In the organic world there are very few substances which do not change by the continuous action of light, and it will be found that as a rule they are affected by the blue end of the spectrum rather than by the red end. For a more detailed account we must refer the reader to The Chemical Effects of the Spectrum by Dr J. M. Eder (London). The following table gives the names of the observers of the action of light on different substances with the date of publication of the several observations. It is nearly identical with one given by Dr Eder in his Gcschichte der Photo-Chcmie. Substance. Observer. Date. Silver. Xitrate solution mixed with chalk, J H Schulze 1727 gives in sunshine copies of writing Xitrate solution on paper Xitrate photographically used Xitrate on silk. - Hellot Wedgwood and Davy .... Fulhame 1737 1802 1797 Xitrate with white of eg a Rumford 1798 1812 Xitrate with lead salts 1839 Chloride J. B. Beccarius 1757 Chloride in the spectrum Chloride photographically used Scheele 1777 1802 Chloride blackened 1839 Iodide Davy 1814 Iodide by action of iodine(on metallic Da &amp;lt;r ueri e 1839 silver) Iodide photographically used. . 1840 Iodide with gallic acid Talbot 1841 Iodide with ferrous sulphate Hunt 1844 Chloride and iodide by chlorine and Claudet 1840 iodine (on metallic silver) Bromide , Balard 1826 Bromide by action of bromine (on 1840 metallic silver) Sulpho-cyanide 1818 Xitrite Hess 1828 Oxide with ammonia Sulphate Chromate Mitscherlich Bergmann 1827 1779 1798 Carbonate 1800 Oxalate 1779 Benzoate Trommsdorf 1793 Citrate 1798 1829 Borate Rose 1830 1830 1833 Formiates Fulminates Hunt Hunt 1844 1844 Sulphide by vapour of sulphur (on Niepce 1820 metallic silver) Phosphide by vapour of phosphorus Xiepce 18-20 (on metallic silver) Gold. Oxide 1777 Chloride on paper Chloride on silk Hellot 1737 1794 Chloride in ethereal solution Chloride with ferro-cyanide and ferri- Rumford Hunt 1793 1844 cyanide of potassium Chloride and oxalic acid Dobereiner 1831 Chromate Plate of gold and iodine vapour .... Hunt Goddard 1844 1842 Platinum. Chloride in ether Gehlen 1804 Chloride with lime &quot;. Herschel 1840 Iodide Bromide ) Herschel Hunt 1840 1844 Cyanide f Double chloride of platinum and Dobereiner 1828 potassium Mercury. Oxide (mercurous) . . Gay-Lussac and Thenard . . 1811 Oxide 1812 Oxide (mercuric) 1797 Abildgaard 1797 Harup not till 1801 Chloride (mercurons) K. Xeurnann previously to 1739 Chloride (mercuric) Boullay 1803 Chloride with oxalic acid Sulphate . . Bergmann Mover. . . 1776 1764 Substance. Observer. Date. Oxalate (mercuric) Ber^mani! . . . 1776 1836 1791 1826 1828 1830 1836 1836 1836 1831 1812 1840 1 B.C. 1877 1725 1782 1831 1808 1818 1783 1S40 1840 1844 1804 1813 1844 1850 1841 1841 1815 1832 1824 1844 1844 1802 1850 1811 1844 1844 1844 1844 1803 1832 1844 1874 1831 1838 1840 1843 1809 1842 1810 1785 1809 1812 1821 1827 1832 Oxalate (mercurous) Hunt Sulphate and ammonia (mercurous) Acetate (mercurous) Fourcroy Garot, . Bromide (mercuric) Lei wig Iodide (mercurous) . ., . J Torosewicz. Iodide (mercuric). . . Field Tartrate and potassium (mercurous) Carbonate (mercuric) Carbonell and Bravo. . . Daw .. Xitrate Ilorschel Sulphide (mercuric). . . Vitnivins. Iron. Sulphate (ferrous) Chastaino. . . Chloride (ferric) and alcohol Bestuscheff Chloride and ether : Klanrotli Oxalate (ferric) Dobereiner Ferro-cyanide of potassium. .. Hcinrich Bulpho-cyanide Grotthus Prussian blue Scopoli Ferric citrate with ammonium.. Herschel Herschel. Clijomate Hunt Copper. Chloride (eupric dissolved in ether) Gehlen A. Vogel Chromate ^ Hunt Chromate with ammonium Carbonate ... }- Iodide. 1 A. Vo&amp;lt;*el. . . Sulphate J Copper plates (iodized) J Kratoch Manganese. Sulphate. . . Brandenburg Oxalate .... Suckow Frommberg Peroxide and cyanide of potassium Chloride Hunt Hunt Lead. Oxide. Davy Iodide ) Sulphite f Gay-Lussac Red lead and cyanide of potassium Acetate Hunt Hunt Nickel. Xitrate Hunt Nitrate with ferro-prussiates . . . . &amp;gt; Iodide j Uncertain. Hunt Tin. Purple of cassius Various Substances. Cobalt Suckow Bismuth salts &quot;i Hunt Roscoe Dobereiner Mungo Ponton Potassium with iodide of starch .... Becquerel Hunt Gay-Lussac and Thenard . . Draper Chlorine and ether Cahours Berthollet Chlorine and ethylene Gay-Lussac and Thenard . . Davy Henry Serullas Balard ... .... Chlorine and carbon-monoxide .... Chlorine and marsh gas Chloride and hydrocyanic acid ....