the blue flame. If the silicate contains copper, a blue coloring ensues in the outer flame. If the mineral containing copper be heated, per se, in the apex of the blue flame, with the exception of Atachamite, the outer flame is colored beautifully green. If the mineral, at the same time, contains much lead, a blue flame, with greenish streaks, results. § 12. SILVER—Ag—Presence in the Mineral Kingdom, and in the products of Smelting Furnaces. Silver occurs in nature: a. Metallic, both per se, and in combination with other metals, namely, as Native Silver [Ag], which is often contaminated with minute portions of Antimony, Arsenic, and Iron; in Native Gold, which contains more or less silver; in Native Amalgam [Ag, 2 Hg] and [Ag, 3 Hg]; with Antimony, in Antimonial Silver [2 Ag, Sb] and [3 Ag, Sb]; with Gold and Tellurium, in Graphic Tellurium [Ag, Te + 3 (Au, 3 Te) ]; with Iron, Arsenic, and a little Antimony, in Arsenical Silver-which is probably a mixture, and not a peculiar species;-with Gold, Tellurium, and Lead, in Yellow Tellurium-Weiss Silvanerz;and with Selenium and Copper, in Eukairite-Selenide of Silver and Copper; 12 As, Ag S b. With Sulphur, both per se, and in combination with other sulphides; thus, per se, in Sulphide of Silver-Silver Glance[Ag S]; with Antimony and a little Copper, in Brittle Sulphide of Silver-Brittle Silver Glance-[6 Ag S + 2 Sb 3 S]; with Arsenic, Copper, and Antimony, in Eugen-glance or Polybasite {2Sb, 38} +9 {2}; with Arsenic, and a very small proportion of Antimony, in Sulphide of Silver and Arsenic, the light red variety of Red or Ruby Silver—it is the Lichtes Rothgiltigerz or Arsensilberblende of the Germans [3 (Ag S), 2 As 3 S]; with Antimony, in Sulphide of Silver and Antimony, the dark red variety of Ruby Silver-Antimonsilberblende of the Germans [3 (Ag S) 2 Sb, 3 S]; with Antimony, a little Copper, and Iron, in Myargyrite-Hemi-Prismatic Ruby Blende-[Ag S, 2 Sb 3 S]; with Copper and a little Iron, in Sulphide of Silver and Copper-Argentiferous Copper Glance;-with Antimony, Copper, a little Iron, and Zinc, in Weissgiltigerz and Graugiltigerz; with Bismuth, Lead, together with a little Iron and Copper, in Bismuthic Silver; with Antimony, Arsenic, Copper, Iron, and Zinc, in Grey Copper; and as a minute constituent in most Lead and Copper ores, to which belong Selenide of Lead, Copper Glance, Copper Pyrites, et cetera. c. In combination with Chlorine, in Chloride of SilverHornsilver-[Ag Cl]; and, d. In combination with Iodine, in Iodic Silver [Ag 2 I]. Silver occurs in the products of smelting furnaces : - 1 Metallic, both per se and in combination with other metals; namely, per se, as Brandsilber—blicksilber refined by cupellation -and Amalgamated Silver-the amalgam of silver and mercury obtained in extracting silver from its ores by the process of amalgamation; it generally contains copper, antimony, et cetera ;with a little Lead, and sometimes minute portions of Copper, in Blicksilber-the crude silver obtained in the refinement of lead for silver, after nearly the whole of the lead has been converted into Litharge;—with Lead, and also with Copper and traces of Antimony, Arsenic, Iron, and Sulphur, in the Workable Lead; as a secondary Constituent in the Black Copper obtained from Copper and Lead ores; and, also, in extremely small quantities, in Abstrich Lead-Abstrich Lead is the Workable Lead from which the Abstrich has been raked off. 2 Combined with Sulphur and other metals, in which, however, it forms only a very minute constituent; namely, in the Bleistein obtained from Sulphide of Lead, and Sulphide of Iron ; in the Kupferstein, from Sulphide of Copper, Sulphide of Lead, and Sulphide of Iron; in the Rohstein, from Sulphide of Iron, and, sometimes, a little Sulphide of Lead and Sulphide of Copper; and in the compound Flue-rakings from the smelting of different sulphides which yield Silver; as also, in a fine mechanically divided state, in the slags obtained by the smelting of Silver ores, or of the argentiferous products of their reduction. 3 In an oxidized state, but only in exceedingly small quantities, as in Litharge, in the Abstrich, and in the Cupel Grounds from which the Workable Lead has been separated. Silver is found also in Tellusilber, Aquerite, Schrifterz, Weisstellur, Tellurblei, Selensilber, Sprodglaserz, Xanthokon, and Sternbergite. Examination for Silver. Some of the minerals, alloys, and furnace products, previously mentioned, are so constituted as to be readily recognizable by their exterior appearance, for silver. To these belong Native Silver, Native Gold of a very light color, Brandsilber, Amalgamated Silver, and Blicksilber. Other argentiferous minerals, when combined with volatile ingredients, give pure silver beads when exposed to a strong oxidating flame, and the charcoal becomes coated with a red sublimate. These are Antimonial Silver, Arsenical Silver, natural and artificial amalgams. When the latter are heated in a glass matrass, mercury volatilizes and deposits in orbicles, which may readily be made to cohere, by tapping the vessel. The residuum, which is nearly freed from the mercury by this process, gives, when smelted on charcoal, a beautiful white globule. If Graphic or Yellow Tellurium be heated on charcoal, an auriferous yellow globule remains, which is composed of gold and silver; by treating this alloy with aqua regia, the gold dissolves and the silver deposits as a chloride. Native gold, containing silver, may also be treated in this manner, when separation is requisite. Those minerals which contain, besides volatile metals, copper, yield a cupreous silver bead when assayed upon charcoal in the oxidating flame. To obtain the silver from these in a pure state, they must be mixed with lead and cupelled.-Eukairite belongs to this class. Silver is detected in Workable Lead, Abstrich-Blei, and in impure Black Copper, by cupelling the first two, per se, and treating the last with ten times its volume of proof lead on charcoal. If it be requisite to examine at once for silver in minerals and furnace products, which consist of metallic sulphides, or only contain such, the quantitative silver examination with proof lead and borax is the most satisfactory method for this object. The necessary information upon this treatment will be given under the above-mentioned examination. Native Chloride of SilverHornsilver fuses on charcoal in the oxidating flame, to a brown, grey, or black bead, which, if pure, gives metallic silver in the reducing flame. This decomposition is immediately effected with soda on charcoal. Furnace products, which contain only a very small quantity of silver, for instance, Litharge, Cupel Grounds, and Abstrich,-must be assayed according to the process given under the quantitative examination of such substances. § 13. MERCURY-Hg-Presence in the Mineral Kingdom, and in the products of Smelting Furnaces. Mercury occurs in nature :— a. Metallic, per se, in Native Mercury [Hg]; and combined with Silver, in Native Amalgam; b. In combination with Sulphur, as Cinnabar, or Sulphide of Mercury, and in Lebererz, or Hepatic Cinnabar [Hg S]; the latter is, however, contaminated with Carbon, Silicic Acid, Oxide of Iron, and other substances; c. In combination with Chlorine, as Chloride of Mercury or Horn Quicksilver [Hg Cl]; and, d. In combination with Iodine, as Iodic Mercury. Mercury also forms a constituent of many products, residues, scoriæ, et cetera, of the amalgamation process for extracting Silver from its ores. To these also belong the products of the amalgamation of Gold and Silver Ores, namely, Gold Amalgam, Silver Amalgam, and the unwashed residue in which finely divided Silver Amalgam is generally present. If the Ores to be amalgamated contain Copper and Lead, these metals will be found in the residues, when the process is completed. Examination for Mercury. Native Mercury possesses all the properties of the pure metal, and need not therefore be more particularly examined, unless it be required to detect traces of other metals present. The combinations of mercury with gold and silver, to which belong both native and artificial amalgams, and also the impure Fig. 44. residues obtained by the washing of silver, copper, and lead amalgams, should be ignited in a flask, or bulb tube-see Fig. 44-over the spiritlamp. The mercury is separated, volatilized, and deposited in the form of small metallic globules in the colder part of the flask or tube, which cannot be confounded with any other metal. In the examination of the compounds of mercury with sulphur, chlorine, or iodine, to which Native Cinnabar, Hepatic Cinnabar, Horn Quicksilver, and Iodic Mercury belong, a portion of the substance should be triturated in an agate mortar, with an equal bulk of soda, the mixture introduced into the small glass vessel, and heated to redness over the spirit-lamp. The sulphur, or chlorine, combines at this temperature with the radical of the soda, forming sulphide or chloride of sodium, while metallic mercury becomes free, ascends as vapor, and condenses on the upper part of the flask in a greyish sublimate, which coheres into small metallic globules on gently tapping the tube. If the quantity of this metal present be so minute that no metallic sublimate of mercury is obtained, the experiment should be repeated in the same manner, introducing at the same time the end of an iron wire, covered with a piece of gold leaf, into the flask, and holding it a little over the surface of the mixture, when the gold becomes perfectly white, or in a great measure so, even when the quantity of mercury present is extremely small. According to WACKENRODER, the haloid salts of mercury give a sublimate on charcoal. The oxygen salts also give, with chloride of sodium,-sulphide of mercury with a mixture of soda and chloride of sodium also,-a heavy or light white vapor and sublimate of subchloride of mercury. If a substance is to be examined for mercury, in which the latter is not combined with sulphur, and which, per se, gives no sublimate, it should be reduced to a fine powder, and fused with dry chloride of sodium on charcoal, |