Page:EB1911 - Volume 21.djvu/524

Rh {|class=_tablecolhdborder
 * -style="text-align: center; border: 1px solid"
 * colspan=2|Substance. ||Observer. ||Date.
 * colspan=2 style=text-align:center|Platinum.|| ||
 * colspan=2|Chloride in ether||Gehieri || 1804
 * colspan=2|Chloride with lime||Herschel || 1840
 * colspan=2|Iodide ||Herschel||1840
 * Bromide||rowspan=2 style="text-align: right; border-style: none none none none"|||rowspan=2|Hunt ||rowspan=2|1844
 * Cyanide
 * colspan=2|Double chloride platinum and potassium||Dobereiner||1828
 * colspan=2 style=text-align:center|Mercury.|| ||
 * colspan=2|Oxide (mercurous) ||Gay-Lussac and Thénard||1811
 * colspan=2|Oxide ||Davy ||1812
 * colspan=2|Oxide (mercuric) ||Davy||1797
 * rowspan="2"|Oxide (more accurate observations)||rowspan=2 style="text-align: right; border-style: none none none none"|||Abidguard||1797
 * Harup not till ||1801
 * colspan=2|Chloride (mercurous)||K. Neumann previous to ||1739
 * colspan=2|Chloride (mercuric) ||Boullay ||1803
 * colspan=2|Chloride with oxalic acid ||Bergmann ||1776
 * colspan=2|Sulphate ||Myer ||1764
 * colspan=2|Oxlate (mercuric)||Bergman||1776
 * colspan=2|Oxlate (mercurous)||Harff||1836
 * colspan=2|Sulphate and ammonia (mercurous)||Fourcroy||1791
 * colspan=2|Acetete (mercurous) ||Garot||1826
 * colspan=2|Bromide (mercuric)|||Lowig||1826
 * rowspan=2|Iodide (mercurous)||rowspan=2 style="text-align: right; border-style: none none none none"|||Torosewicz||1836
 * Artus||1836
 * colspan=2|Iodide (mercuric)||Field||1836
 * colspan=2|Citrate (mercuric)||Harf||1836
 * colspan=2|Tartrate and potassium (mercurous)||Carbonell and Bravo||1831
 * colspan=2|Carbonate (mercuric)||Davy||1812
 * colspan=2|Nitrate||Herschel ||1840
 * colspan=2|Sulphide (mercuric)||Viruvius ||1
 * colspan=2 style=text-align:center|Iron.|| ||
 * colspan=2|Sulphate (ferrous) ||Chastaing ||1877
 * colspan=2|Chloride (ferric) and alchol ||Bestuscheff ||1725
 * colspan=2|Chloride and ether ||Klaproth ||1725
 * colspan=2|Oxalate (ferric) ||Dobereiner ||1831
 * colspan=2|Ferrocyanide of potassium ||Henrich ||1808
 * colspan=2|Sulphocyanide ||Grotthus ||1818
 * colspan=2|Prussian blue ||Scopoli ||1783
 * colspan=2|Ferric citrate with ammonium ||Herschel ||1840
 * colspan=2|Ferric tartrate ||Herschel ||1840
 * colspan=2|Chromate ||Hunt ||1844
 * colspan=2 style=text-align:center|Copper.|| ||
 * colspan=2|Chloride (cupric dissolved in ether)||Gehlen ||1804
 * colspan=2|Oxalate with sodium||A. Vogel ||1813
 * Chromate||rowspan="5" style="text-align: right; border-style: none none none none"|||rowspan="5"|Hunt ||rowspan="5"|1844
 * Chromate with ammonium
 * Carbonate
 * Iodide
 * Sulphate
 * colspan=2|Chloride (cuprous)||A. Vogel ||1859
 * rowspan="2"|Copper plates (iodized)||rowspan="2" style="text-align: right; border-style: none none none none"|||Kratoch ||1841
 * Talbot||1841
 * colspan=2 style="text-align: center;"|Manganese.|| ||
 * colspan=2|Sulphate|| Brandenburg||1815
 * colspan=2|Oxalate||Suckow ||1813
 * colspan=2|Potassium permanganate||Frommberg ||1824
 * colspan=2|Peroxide and cyanide of potassium||Hunt||1844
 * colspan=2|Chloride||Hunt||1844
 * colspan=2 style="text-align: center;"|Lead. || ||
 * colspan=2|Oxide||Davy ||1802
 * Iodide||rowspan="2" style="text-align: right; border-style: none none none none"|||rowspan="2"|Schonbein ||rowspan="2"|1850
 * Sulphite
 * colspan=2|Peroxide||Gay-Lussac||1811
 * colspan=2|Red lead and cyanide of potassium||Hunt||1844
 * colspan=2|Acetate||Hunt||1844
 * colspan=2 style="text-align: center;"|Nickel. || ||
 * Nitrate||rowspan="3" style="text-align: right; border-style: none none none none"|||rowspan="3"|Hunt ||rowspan="3"|1844
 * Nitrate with ferro-prussiates
 * Iodide
 * colspan=2 style="text-align: center;"|Tin. || ||
 * colspan=2|Purple of cassius||Uncertain ||
 * colspan=2 style="text-align: center;"|Various Substances. || ||
 * colspan=2|Cobalt salts||Hunt ||1844
 * colspan=2|Arsenic sulphide (realgar)||Sage ||1803
 * colspan=2|Antimony Sulphide||Suckow ||1832
 * Bismuth salts||rowspan=3 style="text-align: right; border-style: none none none none"|||rowspan=3|Hunt ||rowspan=3|1844
 * Cadmium salts
 * Rhodium salts
 * colspan=2|Vanadic salts||Roscoe ||1874
 * colspan=2|Iriduim ammonium chloride||Dobereiner ||1831
 * colspan=2|Potassium bichromate||Mungo Ponton||1838
 * colspan=2|Potassium with iodide of starch||Becquerel||1840
 * colspan=2|Metallic chromates||Hunt||1843
 * colspan=2|Chlorine and hydrogen ||Gay-Lussac and Thénard||1809
 * colspan=2|Chlorine (tithonized)||Draper||1842
 * colspan=2|Chlorine and ether||Calhours ||1810
 * colspan=2|Chlorine in water||Bertollet ||1785
 * colspan=2|Chlorine and ethylene||Gay-Lussac and Thénard||1809
 * colspan=2|Chlorine and canon-monoxide|| Davy||1812
 * colspan=2|Chlorine and Hydrocyanic acid|| Henry||1821
 * colspan=2|Bromide and hydrogen|| Balard||1832
 * colspan=2|Iodine and ethylene|| Faraday||1821
 * colspan=2|Cyanogen, solution of|| Pelouze and Richardson||1837
 * colspan=2|Various other Methyl compounds||Cahours ||1846
 * colspan=2|Hydrocyanic acid|| Totosewicz||1836
 * colspan=2|Hypochlorites (calcium and potassium)|| Dobereiner||1813
 * colspan=2|Uranium chloride and ether|| Gehlen||1804
 * colspan=2|Molybdenite of potassium and tin salts||Jager ||1800
 * rowspan=3|Crystallization and slats under influence of light||rowspan=3 style="text-align: right; border-style: none none none none"|
 * Cahours ||1846
 * Chapptal||1788
 * Dize||1789
 * colspan=2|Phosphorous (in hydrogen, nitrogen &c.)||Brockmann ||1800
 * colspan=2|Phosphuretted hydrogen||A. Volel ||1812
 * colspan=2|Natric acid||Scheele || 1777
 * colspan=2|Hog’s fat||Vogle || 1806
 * colspan=2|Palm oil||Fier || 1832
 * colspan=2|Asphalt||Niepce || 1814
 * colspan=2|Resins (mastic, sandarac, gamboge, ammoniacum, &c.) ||Senebier ||1782
 * colspan=2|Guaiacum||Hagemann ||1782
 * colspan=2|Bitumens all decomposed, all residues of essential oils||Daguerre ||1839
 * colspan=2|Coloured extracts from flowers||Senebier ||1782
 * colspan=2|Similar colouring matters spread upon paper||Herschel ||1842
 * colspan=2|Yellow wax bleached|| Pliny ||1st cent.&thinsp;
 * colspan=2|Eudoxia macrembolitissa (purple dye)|| ||10th cent.
 * rowspan="2"|Other purple dyes||rowspan="2" style="text-align: right; border-style: none none none none"|
 * Cole ||1684
 * Réaumur ||1711
 * colspan=2|Oils generally||Senebier||1782
 * colspan=2|Nitric ether||Senebier||1782
 * colspan=2|Nioctine|| Henry & Boutron-Charlard||1836
 * colspan=2|Santonine||Merk ||1888
 * }
 * Sulphite
 * colspan=2|Peroxide||Gay-Lussac||1811
 * colspan=2|Red lead and cyanide of potassium||Hunt||1844
 * colspan=2|Acetate||Hunt||1844
 * colspan=2 style="text-align: center;"|Nickel. || ||
 * Nitrate||rowspan="3" style="text-align: right; border-style: none none none none"|||rowspan="3"|Hunt ||rowspan="3"|1844
 * Nitrate with ferro-prussiates
 * Iodide
 * colspan=2 style="text-align: center;"|Tin. || ||
 * colspan=2|Purple of cassius||Uncertain ||
 * colspan=2 style="text-align: center;"|Various Substances. || ||
 * colspan=2|Cobalt salts||Hunt ||1844
 * colspan=2|Arsenic sulphide (realgar)||Sage ||1803
 * colspan=2|Antimony Sulphide||Suckow ||1832
 * Bismuth salts||rowspan=3 style="text-align: right; border-style: none none none none"|||rowspan=3|Hunt ||rowspan=3|1844
 * Cadmium salts
 * Rhodium salts
 * colspan=2|Vanadic salts||Roscoe ||1874
 * colspan=2|Iriduim ammonium chloride||Dobereiner ||1831
 * colspan=2|Potassium bichromate||Mungo Ponton||1838
 * colspan=2|Potassium with iodide of starch||Becquerel||1840
 * colspan=2|Metallic chromates||Hunt||1843
 * colspan=2|Chlorine and hydrogen ||Gay-Lussac and Thénard||1809
 * colspan=2|Chlorine (tithonized)||Draper||1842
 * colspan=2|Chlorine and ether||Calhours ||1810
 * colspan=2|Chlorine in water||Bertollet ||1785
 * colspan=2|Chlorine and ethylene||Gay-Lussac and Thénard||1809
 * colspan=2|Chlorine and canon-monoxide|| Davy||1812
 * colspan=2|Chlorine and Hydrocyanic acid|| Henry||1821
 * colspan=2|Bromide and hydrogen|| Balard||1832
 * colspan=2|Iodine and ethylene|| Faraday||1821
 * colspan=2|Cyanogen, solution of|| Pelouze and Richardson||1837
 * colspan=2|Various other Methyl compounds||Cahours ||1846
 * colspan=2|Hydrocyanic acid|| Totosewicz||1836
 * colspan=2|Hypochlorites (calcium and potassium)|| Dobereiner||1813
 * colspan=2|Uranium chloride and ether|| Gehlen||1804
 * colspan=2|Molybdenite of potassium and tin salts||Jager ||1800
 * rowspan=3|Crystallization and slats under influence of light||rowspan=3 style="text-align: right; border-style: none none none none"|
 * Cahours ||1846
 * Chapptal||1788
 * Dize||1789
 * colspan=2|Phosphorous (in hydrogen, nitrogen &c.)||Brockmann ||1800
 * colspan=2|Phosphuretted hydrogen||A. Volel ||1812
 * colspan=2|Natric acid||Scheele || 1777
 * colspan=2|Hog’s fat||Vogle || 1806
 * colspan=2|Palm oil||Fier || 1832
 * colspan=2|Asphalt||Niepce || 1814
 * colspan=2|Resins (mastic, sandarac, gamboge, ammoniacum, &c.) ||Senebier ||1782
 * colspan=2|Guaiacum||Hagemann ||1782
 * colspan=2|Bitumens all decomposed, all residues of essential oils||Daguerre ||1839
 * colspan=2|Coloured extracts from flowers||Senebier ||1782
 * colspan=2|Similar colouring matters spread upon paper||Herschel ||1842
 * colspan=2|Yellow wax bleached|| Pliny ||1st cent.&thinsp;
 * colspan=2|Eudoxia macrembolitissa (purple dye)|| ||10th cent.
 * rowspan="2"|Other purple dyes||rowspan="2" style="text-align: right; border-style: none none none none"|
 * Cole ||1684
 * Réaumur ||1711
 * colspan=2|Oils generally||Senebier||1782
 * colspan=2|Nitric ether||Senebier||1782
 * colspan=2|Nioctine|| Henry & Boutron-Charlard||1836
 * colspan=2|Santonine||Merk ||1888
 * }
 * colspan=2|Cyanogen, solution of|| Pelouze and Richardson||1837
 * colspan=2|Various other Methyl compounds||Cahours ||1846
 * colspan=2|Hydrocyanic acid|| Totosewicz||1836
 * colspan=2|Hypochlorites (calcium and potassium)|| Dobereiner||1813
 * colspan=2|Uranium chloride and ether|| Gehlen||1804
 * colspan=2|Molybdenite of potassium and tin salts||Jager ||1800
 * rowspan=3|Crystallization and slats under influence of light||rowspan=3 style="text-align: right; border-style: none none none none"|
 * Cahours ||1846
 * Chapptal||1788
 * Dize||1789
 * colspan=2|Phosphorous (in hydrogen, nitrogen &c.)||Brockmann ||1800
 * colspan=2|Phosphuretted hydrogen||A. Volel ||1812
 * colspan=2|Natric acid||Scheele || 1777
 * colspan=2|Hog’s fat||Vogle || 1806
 * colspan=2|Palm oil||Fier || 1832
 * colspan=2|Asphalt||Niepce || 1814
 * colspan=2|Resins (mastic, sandarac, gamboge, ammoniacum, &c.) ||Senebier ||1782
 * colspan=2|Guaiacum||Hagemann ||1782
 * colspan=2|Bitumens all decomposed, all residues of essential oils||Daguerre ||1839
 * colspan=2|Coloured extracts from flowers||Senebier ||1782
 * colspan=2|Similar colouring matters spread upon paper||Herschel ||1842
 * colspan=2|Yellow wax bleached|| Pliny ||1st cent.&thinsp;
 * colspan=2|Eudoxia macrembolitissa (purple dye)|| ||10th cent.
 * rowspan="2"|Other purple dyes||rowspan="2" style="text-align: right; border-style: none none none none"|
 * Cole ||1684
 * Réaumur ||1711
 * colspan=2|Oils generally||Senebier||1782
 * colspan=2|Nitric ether||Senebier||1782
 * colspan=2|Nioctine|| Henry & Boutron-Charlard||1836
 * colspan=2|Santonine||Merk ||1888
 * }
 * colspan=2|Resins (mastic, sandarac, gamboge, ammoniacum, &c.) ||Senebier ||1782
 * colspan=2|Guaiacum||Hagemann ||1782
 * colspan=2|Bitumens all decomposed, all residues of essential oils||Daguerre ||1839
 * colspan=2|Coloured extracts from flowers||Senebier ||1782
 * colspan=2|Similar colouring matters spread upon paper||Herschel ||1842
 * colspan=2|Yellow wax bleached|| Pliny ||1st cent.&thinsp;
 * colspan=2|Eudoxia macrembolitissa (purple dye)|| ||10th cent.
 * rowspan="2"|Other purple dyes||rowspan="2" style="text-align: right; border-style: none none none none"|
 * Cole ||1684
 * Réaumur ||1711
 * colspan=2|Oils generally||Senebier||1782
 * colspan=2|Nitric ether||Senebier||1782
 * colspan=2|Nioctine|| Henry & Boutron-Charlard||1836
 * colspan=2|Santonine||Merk ||1888
 * }
 * Cole ||1684
 * Réaumur ||1711
 * colspan=2|Oils generally||Senebier||1782
 * colspan=2|Nitric ether||Senebier||1782
 * colspan=2|Nioctine|| Henry & Boutron-Charlard||1836
 * colspan=2|Santonine||Merk ||1888
 * }
 * colspan=2|Nioctine|| Henry & Boutron-Charlard||1836
 * colspan=2|Santonine||Merk ||1888
 * }
 * colspan=2|Santonine||Merk ||1888
 * }

Effect of Hydrogen Peroxide on Sensitive Plates.—Dr W. J. Russell made a series of experiments on the effect of exposure of sensitive plates to the action of vapours and gases for long periods. It has long been known that contact of plates with such substances as wood caused a sensitive surface to so “fog” on development. By a somewhat exhaustive series of experiments, Russell showed that the probable cause of this fog is hydrogen peroxide, since substances which favoured its formation produced the same effect. This is somewhat remarkable, as this same substance will completely destroy the effect that light has had on a sensitive plate; indeed, it affords one way of destroying a light image on a sensitive collodion plate. The experiment of Russell give a warning to store exposed plates for brief periods. It appears that negatives wrapped in paraffin paper are secure from this danger.

The Application of Photography to Quantitative Measures.—In order to employ photography for the measurement of light it was necessary that some means should be devised by which the opacity of the deposit produced on the development of a plate could be determined. It is believed that in 1874 the first attempt was made by Sir W. Abney to do this. In the ''Phil. Mag.'' he showed how density could be measured by means of an instrument, the diaphanometer, he had devised, in which transparent