We also give an Analytical Table for the 1st Section of this subdivision, on account of the great number and importance of the metals it contains. Analysis of Subdivision IV. SECTION I. Salts of metals which form Sulphides insoluble in Sulphide of Ammonium. The salt may be one of CADMIUM, COPPER, SILVER, MERCURY (mercurous or mercuric), LEAD, BISMUTH, or PALLADIUM. Ignite the substance; if it does not volatilize, we infer the presence of absence of Mercury, Cadmium, Copper, Silver, Lead, Bismuth, or Palladium. which may Dissolve the ignited residue in a little nitric acid, dilute be further with water, and add dilute sulphuric acid; if no white preconfirmed cipitate is produced, we infer the by heating the dry salt mixed with dry Na CO in a small tube and observing the absence of globules. absence of presence of Cadmium, Copper, Silver, Bismuth, or To the same solution add dilute hydrochloric acid; if no precipitate is produced, we infer the SECTION II.-Salts of metals which form sulphides soluble in Sulphide of ammonium ([NH], S). SALTS OF TIN, ANTIMONY, ARSENIC, PLATINUM, RHODIUM, RUTHENIUM, OSMIUM, GOLD, TUNGSTEN, MOLYBDENUM, and VANADIUM. SALTS OF TIN. The chemical characteristics of the compounds of this metal resemble to a certain extent those of the preceding: it forms two series of combinations with chlorine and acid-radicals in general, -the stannous chloride and oxide (SnCl and Sn2O) being representatives of the first, and the stannic chloride and oxide (SnCl2 and Sn,O,) typifying the second series. Stannic salts, however, are far more numerous and important than palladic salts; and so far from having, like them, a tendency to decompose into the acidradical and the corresponding salt of the first series, they are actually produced easily from stannous salts,-half of the metal present being separated in the metallic state, while the portion of acid-radical previously united with this half combines with the residual elements: thus stannous oxide, under peculiar circumstances, passes into stannic oxide, thus 2(Sn, 0)=28n+Sn, O,. Besides these two series there is a third, which is, however, unimportant, few members of it existing: it is intermediate between the stannous and stannic series, and has been called the stannosostannic series, while its members have been termed sesquisalts. When salts of tin are heated in the oxidizing flame of the blowpipe, they are converted into an intermediate oxide (Sn ̧ O ̧), at least for the most part; several tin salts, however, as stannous chloride (SnCl), partially volatilize, while in the reducing flame tin salts yield their metal; but to effect this requires some skill in the operator, and may be taken as a test of proficiency in the use of the reducing flame: fluxes, such as carbonate of sodium or cyanide of potassium, should not be employed, since the operation is deprived of all difficulty by their aid. Tin salts impart no colour to the flame; but with nitrate of cobalt the residual oxide (Sn ̧0) assumes a bluish-green colour. When fused with borax in the oxidizing flame, they yield a colourless transparent glass, which, if surcharged with the tin salt, becomes opaque and crystalline in the reducing flame, part of the tin present is reduced to the metallic state; this experiment should be performed on charcoal. Although the salts of tin are placed together in the second section of the present subdivision, that is, among those metals the sulphides of which are capable of forming sulphur salts with the alkaline sulphides, yet, properly speaking, the stannous salts should belong to Section I., and the stannic salts to Section II., for the stannous sulphide (Sn, S) does not dissolve as such in sulphide of ammonium, but only after its conversion into stannic sulphide by combination with the sulphur which sulphide of ammonium usually holds in solution; thus Sn, S+(NH), S+S=(NH ̧), Sn, S. Stannous salts are reduced by iron under certain circumstances, readily by zinc and cadmium, slightly by lead. The same actions are observed with such stannic salts as are soluble. STANNOUS SALTS, OR PROTO-SALTS OF TIN. Solution for the reactions:-proto-chloride of tin (SnCl) in water. The principal insoluble salts of this series are the iodide, the cyanide, the chromate, the oxychloride, the hydrate, the sulphide, the oxalate, the ferrocyanide, the ferricyanide, and the phosphate. THE CHLORIDE is soluble. The Iodide is obtained by the action of iodide of potassium in excess on solutions of stannous salts, especially after some time. It is a yellowish white precipitate; but from warm solutions it separates in fine reddish yellow crystals. Its formula is SnI. It dissolves sparingly in cold water, but more readily in hot; it is also soluble in a solution of stannous chloride. THE CYANIDE is produced by the action of cyanide of potassium on solutions of stannous salts: it is a white precipitate, which is |