Part III

SPECIAL REACTIONS; OR, THE BEHAVIOR OF SUBSTANCES BEFORE THE BLOWPIPE.

Analytical chemistry may be termed the art of converting the unknown constituents of substances, by means of certain operations, into new combinations which we recognize through the physical and chemical properties which they manifest.

It is, therefore, indispensably necessary, not only to be cognizant of the peculiar conditions by which these operations can be effected, but it is absolutely necessary to be acquainted with the forms and combinations of the resulting product, and with every modification which may be produced by altering the conditions of the analysis.

We shall first give the behavior of simple substances before the blowpipe; and the student should study this part thoroughly, by repeating each reaction, so that he can acquire a knowledge of the color, form, and physical properties in general, of the resulting combination. There is nothing, perhaps, which will contribute more readily to the progress of the pupil, than thorough practice with the reactions recommended in this part of the work, for when once the student shall have acquired a practical eye in the discernment of the peculiar appearances of substances after they have undergone the decompositions produced by the strong heat of the blowpipe flame, together with the reactions incident to these changes, then he will have greatly progressed in his study, and the rest will be comparatively simple.

A. METALLIC OXIDES.

GROUP FIRST.--THE ALKALIES: POTASSA, SODA, AMMONIA, AND LITHIA.

The alkalies, in their pure, or carbonated state, render reddened litmus paper blue. This is likewise the case with the sulphides of the alkalies. The neutral salts of the alkalies, formed with the strong acids, do not change litmus paper, but the salts formed with the weak acids, render the red litmus paper blue; for instance, the alkaline salts with boracic acid. Fused with borax, soda, or microcosmic salt, they give a clear bead. The alkalies and their salts melt at a low red heat. The alkalies cannot be reduced to the metallic state before the blowpipe. They are not volatile when red hot, except the alkali ammonia, but they are volatile at a white heat.

(_a._) _Potassa._(KO).--It is not found free, but in combination with inorganic and organic acids, as well in the animal as in the vegetable organism, as in the mineral kingdom. In the pure, or anhydrous state, or as the carbonate, potassa absorbs moisture, and becomes fluid, or is deliquescent, as it is termed. By exposing potassa, or its easily fusible salts (except the phosphate or borate), upon platinum wire, to the point of the blue flame, there is communicated to the external flame a violet color, in consequence of a reduction and reoxidation. This color, though characteristic of all the potassa compounds, is scarcely visible with the phosphate or borate salts of that alkali. The admixture of a very little soda (1/300th) destroys the color imparted by the potassa, while the flame assumes a yellow color, characteristic of the soda. The presence of lithia changes the violet color of the potash into red. The silicates of potassa must exist in pretty large proportion before they can be detected by the violet color of the flame, and those minerals must melt easily at the edges. The presence of a little soda in these instances conceals the reaction in the potassa entirely.

If alcohol is poured over potassa compounds which are powdered, and then set on fire, the external flame appears violet-colored, particularly when stirred with a glass rod, and when the alcohol is really consumed. The presence of soda in lithia will, in this case likewise, hide by their own characteristic color, that of the potassa.

The salts of potassa are absorbed when fused upon charcoal. The sulphur, bromine, chlorine, and iodine compounds of potassa give a white, but easily volatile sublimate upon the charcoal, around the place where the fused substance reposed. This white sublimate manifests itself only when the substance is melted and absorbed within the charcoal, and ceases to be visible as soon as it is submitted to the reducing flame, while the external flame is colored violet; sulphate of potassa, for instance, is reduced by the glowing charcoal into the sulphide. This latter is somewhat volatile, but by passing through the oxidation flame, it is again oxidized into the sulphate. This, being less volatile, sublimes upon the charcoal, but by exposing it again to the flame of reduction, it is reduced and carried off to be again oxidized by its passage through the oxidation flame.

Potassa and its compounds give, with soda, borax or microcosmic salt, as well when hot as cold, colorless beads, unless the acid associated with the alkali should itself produce a color. When borax is fused with some pure boracic acid, and sufficient of the oxide of nickel is added, so that the beads appear of a brown color after being cooled, and then the bead thus produced fused with the substance suspected to contain potassa, in the oxidation flame, the brown color is changed to blue. The presence of the other alkalies does not prevent this reaction. As it is not possible to detect potassa compounds with unerring certainty by the blowpipe flame, the the wet method should be resorted to for the purpose of confirming it.

The _silicates of potassa_ must be prepared as follows, for analytical purposes by the wet way. Mix one part of the finely powdered substance with two parts of soda (free from potassa), and one part of borax. Fuse the mixture upon charcoal in the oxidation flame to a clear, transparent bead. This is to be exposed again with the pincers to the oxidation flame, to burn off the adhering coal particles. Then pulverize and dissolve in hydrochloric acid to separate the silica; evaporate to dryness, dissolve the residue in water, with the admixture of a little alcohol, and test the filtrate with chloride of platinum for potassa.

(_b._) _Soda_ (NaO).--This is one of the most abundant substances, although seldom found free, but combined with chlorine or some other less abundant compound. Soda, its hydrate and salts manifest in general the same properties as their respective potash compounds; but the salts of soda mostly contain crystal water, which leaves the salts if they are exposed to the air, and the salts effervesce.

By exposing soda or its compounds upon a platinum wire to the blue flame, a reddish-yellow color is communicated to the external flame, which appears as a long brilliant stream and considerably increased in volume. The presence of potash does not prevent this reaction of soda. If there is too large a quantity of potash, the flame near to the substance is violet-colored, but the edge of the flame exhibits the characteristic tint of the soda. The presence of lithia changes the yellow color to a shade of red.

When alcohol is poured over powdered soda compounds and lighted, the flame exhibits a reddish-yellow color, particularly if the alcohol is stirred up with a glass rod, or if the alcohol is nearly consumed.

Fused upon charcoal, soda compounds are absorbed by the coal. The sulphide, chloride, iodide, and bromide of soda yield a white sublimate around the spot where the substance is laid, but this sublimate is not so copious as that of the potash compounds, and disappears when touched with the reduction flame, communicating a yellow color to the external flame. The presence of soda in compounds must likewise be confined by reactions in the wet way.

(_c._) _Ammonia_ (NH^{4}O).--In the fused state, and at the usual temperature, ammonia is a pungent gas, and exerts a reaction upon litmus paper similar to potash and soda. Ammonium is considered by chemists as a metal, from the nature of its behavior with other substances. It has not been isolated, but its existence is now generally conceded by all chemists. The ammonia salts are volatile, and many of them sublimate without being decomposed.

The salts of ammonia, on being heated in the point of the blue flame, produce a feeble green color in the external flame, just previous to their being converted into vapor. But this color is scarcely visible, and presents nothing characteristic. When the ammonia salts are mixed with the carbonate of soda, and heated in a glass tube closed at one end, carbonate of ammonia is sublimed, which can be readily recognized by its penetrating smell of spirits of hartshorn.

This sublimate will render blue a slip of red litmus paper. This can be easily done by moistening the litmus paper, and then inserting the end of it in the tube. By holding a glass rod, moistened with dilute hydrochloric acid, over the mouth of the tube, a white vapor is instantly rendered visible (sal ammoniac).

(_d._) _Lithia_ (LiO).--In the pure state, lithia is white and crystalline, not easily soluble in water, and does not absorb moisture. It changes red litmus to blue, and at a low red heat it melts. Lithia or its salts, exposed to the point of the blue flame, communicates a red color to the external or oxidation flame, in consequence of a reduction, sublimation, and re-oxidation of the lithia. An admixture of potash communicates to this flame a reddish-violet color, and the presence of soda that of a yellowish-red or orange. If the soda, however, is in too great proportion, then its intense yellow hides the red of the lithia. In the latter case the substance under test must be only imperfectly fused in the oxidation flame, and then dipped in wax or tallow. By exposing it now to the reduction flame, the red color imparted to the external flame by the lithia becomes visible, even if a considerable quantity of soda be present. A particular phenomenon appears with the phosphate of lithia, viz., the phosphoric acid itself possesses the property of communicating to the flame a bluish-green color. By its combination with lithia it still exhibits its characteristic color, while the latter presents likewise its peculiar tint. Then we perceive a green flame in the centre of the flame, while the red color of lithia surrounds it.

The _silicates_, which contain only a little lithia, produce only a slight hue in the flame, and often none at all. We have to mix one part of the silicate with two parts of a mixture composed of one part of fluorspar and one and a half parts of bisulphate of potassa. Moisten the mass with water so that the mass will adhere, and then melt it upon a platinum wire in the reduction flame, when that of oxidation will present the red color of lithia.

The _Borates of lithia_ produce at first a green color, but it soon yields to the red of lithia. When alcohol is poured over lithia or its compounds, and inflamed, it burns with a deep red color, particularly if the fluid is stirred up with a glass rod, or when the alcohol is nearly consumed. This color presents the same modifications as the corresponding ones communicated to the blowpipe as mentioned above.

The salts of lithia are absorbed by charcoal when fused upon it. The sulphide, bromide, iodide, and chloride of lithia produce upon the charcoal a greyish-white sublimate, although not so copiously as the corresponding compounds of potash and soda. This sublimate disappears when touched by the reduction flame, while the oxidation flame gives the characteristic color of lithia.

SECOND GROUP.--THE ALKALINE EARTHS, BARYTA, STRONTIA, LIME, AND MAGNESIA.

In the pure state, the alkaline earths are caustic, cause red litmus paper to become blue, and are more or less soluble in water. Their sulphides are also soluble. The carbonates and phosphates of the alkaline earths are insoluble in water. By igniting the carbonates, their carbonic acid is expelled, and the alkaline earths are left in the caustic state. The alkaline earths are not volatile, and their organic salts are converted, by ignition, into carbonates.

(_a._) _Baryta._ (BaO).--This alkaline earth does not occur free in nature, but combined with acids, particularly with carbonic and sulphuric acids. In the pure state, baryta is of a greyish-white color, presents an earthy appearance, and is easily powdered. When sparingly moistened with water, it slakes, becomes heated, and forms a dry, white powder. With still more water it forms a crystalline mass, the hydrate of baryta, which is completely soluble in hot water. Pure baryta is infusible; the hydrate fuses at a red heat, without the loss of its hydratic water; if caustic baryta is exposed for too great a length of time to the flame, it absorbs water, originated by the combustion, and becomes a hydrate, when it will melt. Salts of baryta, formed with most acids, are insoluble in water; for instance, the salts with sulphuric, carbonic, arsenic, phosphoric, and boracic acids. The salts of baryta, soluble in water, are decomposed by ignition, except the chloride.

Carbonate of baryta loses its carbonic acid at a red heat, becomes caustic, and colors red litmus paper blue.

By exposing baryta or its compounds upon a platinum wire, or a splinter of the substance held with the platinum tongs, to the point of the blue flame, a pale apple-green color is communicated to the external flame. This color appears at first very pale, but soon becomes more intense. This color is most visible if the substance is operated with in small quantities. The chloride of barium produces the deepest color. This color is less intense if the carbonate or sulphate is used. The presence of strontia, lime, or magnesia, does not suppress the reaction of the baryta, unless they greatly predominate.

When alcohol is poured over baryta or its salts, and inflamed, a feeble green color is communicated to the flame, but this color should not be considered a characteristic of the salt.

Baryta and its compounds give, when fused with carbonate of soda upon platinum foil, a clear bead. Fused with soda upon charcoal, it is absorbed. The sulphate fuses at first to a clear bead, which soon spreads, and is absorbed and converted while boiling into a hepatic mass. If this mass is taken out, placed upon a piece of polished silver and moistened with a little water, a black spot of sulphide of silver is left after washing off the mass with water.

Borax dissolves baryta and its compounds with a hissing noise, as well in the flame of oxidation as in that of reduction. There is formed a clear bead which, with a certain degree of saturation, is clear when cold, but appears milk-white when overcharged, and of an opal, enamel appearance, when heated intermittingly, or with a vacillating flame, that changes frequently from the oxidating to the reducing flame. Baryta and its compounds produce the same reactions with microcosmic salt.

Baryta and its compounds fuse when exposed to ignition in the oxidizing flame. Moistened with the solution of nitrate of cobalt, and heated in the oxidation flame, it presents a bead, colored from brick-red to brown, according to the quantity used. This color disappears when cold, and the bead falls to a pale grey powder after being exposed awhile to the air. When heated again, the color does not appear until fusion is effected. If carbonate of soda is fused upon platinum wire with so much of the sesquioxide of manganese that a green bead is produced, this bead, when fused with a sufficient quantity of baryta, or its compounds, after cooling, will appear of a bluish-green, or light blue color.

(_b._) _Strontia_ (SrO).--Strontia and its compounds are analogous to the respective ones of baryta. The hydrate of strontia has the same properties as the hydrate of baryta, except that it is less soluble in water. The carbonate of strontia fuses a little at a red heat, swells, and bubbles up like cauliflower. This produces, in the blowpipe flame, an intense and splendid light, and now produces an alkaline reaction upon red litmus paper. The sulphate of strontia melts in the oxidation flame upon platinum foil, or upon charcoal, to a milk-white globule. This fuses upon charcoal, spreads and is reduced to the sulphide, which is absorbed by the charcoal. It now produces the same reactions upon polished silver as the sulphate of baryta under the same conditions. By exposing strontia and its compounds upon platinum wire, or as a splinter with the platinum tongs, to the point of the blue flame, the external flame appears of an intense crimson color. The deepest red color is produced by the chloride of strontium, particularly at the first moment of applying the heat. After the salt is fused, the red color ceases to be visible in the flame, by which it is distinguished from the chloride of lithium. The carbonate of strontia swells up and produces a splendid white light, while the external flame is colored of a fine purple-red. The color produced by the sulphate of strontia is less intense. The presence of baryta destroys the reaction of the strontia, the flame presenting the light green color of the baryta.

If alcohol is poured over powdered strontia and inflamed, the flame appears purple or deep crimson, particularly if the fluid is stirred with a glass rod, and when the alcohol is nearly consumed.

The insoluble salts of strontia do not produce a very intense color. Baryta does not prevent the reaction of the soluble salts of strontia, unless it exists greatly in excess. In the presence of baryta, strontia can be detected by the following process: mix some of the substance under examination with some pure graphite and water, by grinding in an agate mortar. Place the mixture upon charcoal, and expose it for a while to the reduction flame. The substance becomes reduced to sulphide of barium and sulphide of strontium, when it should be dissolved in hydrochloric acid. The solution should be evaporated to dryness, redissolved in a little water, and enough alcohol added that a spirit of 80 per cent. is produced. Inflame the spirit, and if strontia is present, the flame is tinged of a red color. This color can be discerned more distinctly by moistening some cotton with this spirit and inflaming it.

If strontia or its compounds are fused with a green bead of carbonate of soda and sesquioxide of manganese, as described under the head of baryta, a bead of a brown, brownish-green, or dark grey color is produced. Carbonate of soda does not dissolve pure strontia. The carbonate and sulphate of strontia melt with soda upon platinum foil to a bead, which is milk-white when cold, but fused upon charcoal they are absorbed. Strontia or its compounds produce with borax, or microcosmic salt, the same reactions as baryta. When they are moistened with nitrate of cobalt, and ignited in the oxidizing flame, a black, or grey infusible mass is produced.

(_c._) _Lime, Oxide of Calcium _(CaO).--Lime does not occur free in nature, but in combination with acids, chiefly the carbonic and sulphuric. The phosphate occurs principally in bones. The hydrate and the salts of lime are in their properties similar to those of the two preceding alkaline earths. In the pure state, the oxide of calcium is white; it slakes, produces a high temperature, and falls into a white powder when sprinkled with a little water. It is now a hydrate, and has greatly increased in volume. The hydrate of lime is far less soluble in water than either those of baryta or strontia, and is less soluble in hot water than in cold. Lime, its hydrate and sulphide of calcium, have a strong alkaline reaction upon red litmus paper. Lime and its hydrate are infusible, but produce at a strong red heat a very intense and splendid white light, while the hydrate loses its water. The carbonate of lime is also infusible, but at a red heat the carbonic acid is expelled, and the residue becomes caustic, appears whiter, and produces an intenser light. The sulphate of lime melts with difficulty, and presents the appearance of an enamelled mass when cold. By heating it upon charcoal it fuses in the reducing flame, and is reduced to a sulphide. This has a strong hepatic odor, and exerts an alkaline reaction upon red litmus paper. By exposing lime, or its compounds, upon platinum wire--or as a small splinter of the mineral in the platinum tongs--to the point of the blue flame, a purple color, similar to that of lithia and strontia, is communicated to the external flame, but this color is not so intense as that produced by strontia, and appears mixed with a slight tinge of yellow. This color is most intense with the chloride of calcium, while the carbonate of lime produces at first a yellowish color, which becomes red, after the expulsion of the carbonic acid. Sulphate of lime produces the same color, but not so intense. Among the silicates of lime only the tablespar (3CaO, 2SiO^{3}) produces a red color. Fluorspar (CaFl) produces a red as intense as pure lime, and fuses into a bead. Phosphate and borate of lime produce a green flame which is only characteristic of their acids. The presence of baryta communicates a green color to the flame. The presence of soda produces only a yellow color in the external flame.

If alcohol is poured over lime or its compounds and inflamed, a red color is communicated to the flame. The presence of baryta or soda prevents this reaction. Lime and its compounds do not dissolve much by fusion with carbonate of soda. If this fusion is effected on charcoal, the carbonate of soda is absorbed and the lime remains as a half-globular infusible mass on the charcoal. This is what distinguishes lime from baryta and strontia, and is a good method of separating the former from the latter. Lime and its compounds fuse with borax in the oxidizing and reducing flames to a clear bead, which remains clear when cold, but when overcharged with an excess or heated intermittingly, the bead appears, when cold, crystalline and uneven, and is not so milk-white as the bead of baryta or strontia, produced under the same circumstances. The carbonate of lime is dissolved with a peculiar hissing noise. Microcosmic salt dissolves a large quantity of lime into a clear bead, which is milky when cold. When the bead has been overcharged with lime, by a less excess, or by an intermittent flame, we will perceive in the bead, when cold, fine crystals in the form of needles. Lime and its compounds form by ignition with nitrate of cobalt, a black or greyish-black infusible mass.

(_d._) _Magnesia_ (MgO).--Magnesia occurs in nature in several minerals. It exists in considerable quantity combined with carbonic, sulphuric, phosphoric, and silicic acids, etc. Magnesia and its hydrate are white and very voluminous, scarcely soluble in hot or cold water, and restores moistened red litmus paper to its original blue color. Magnesia and its hydrate are infusible, the latter losing its water by ignition. The carbonate of magnesia is infusible, loses its carbonic acid at a red heat, and shrinks a little. It now exerts upon red litmus paper an alkaline reaction. The sulphate of magnesia, at a red heat, loses its water and sulphuric acid, is entirely infusible, and gives now an alkaline reaction. The artificial Astrachanit (NaO, SO^{3} + MgO, SO^{3} + 4HO) fuses easily. When fused on charcoal, the greater part of the sulphate of soda is absorbed, and there remains an infusible mass.

Magnesia and its compounds do not produce any color in the external flame, when heated in the point of the blue flame. The most of the magnesia minerals yield some water when heated in a glass tube closed at one end.

Magnesia, in the pure state, or as the hydrate, does not fuse with soda. Some of its compounds are infusible likewise with soda, and swell up slightly, while others of them melt with soda to a slightly opaque mass. Some few (such as the borate of magnesia) give a clear bead with soda, though it becomes slightly turbid by cooling when saturated with magnesia, and crystallizes in large facets.

Magnesia and its compounds give beads with borax and microcosmic salt similar to those of lime. By igniting magnesia or its compounds very strongly in the oxidizing flame, moistening with nitrate of cobalt, and re-igniting in the oxidation flame, they present, after a continued blowing, a pale flesh-color, which is more visible when cold. It is indispensable that the magnesia compounds should be completely white and free of colored substances, or the color referred to cannot be discerned. In general the reactions of magnesia before the blowpipe are not sufficient, and it will be necessary to confirm its presence or absence by aid of reagents applied in the wet way.

THIRD GROUP.--THE EARTHS, ALUMINA, GLUCINA, YTTRIA, THORINA, AND ZIRCONIA.

The substances of this group are distinguished from the preceding by their insolubility in water, in their pure or hydrated state--that they have no alkaline reaction upon litmus paper, nor form salts with carbonic acid. The earths are not volatile, and, in the pure state, are infusible. They cannot be reduced to the metallic state before the blowpipe. The organic salts are destroyed by ignition, while the earths are left in the pure state, mixed with charcoal, from the organic acids. The most of their neutral salts are insoluble in water; the soluble neutral salts change blue litmus paper to red, and lose their acids when ignited.

(_a._) _Alumina_ (Al^{2}O^{3}).--This earth is one of our most common minerals. It occurs free in nature in many minerals, as sapphire, etc.; or in combination with sulphuric acid, phosphoric acid, and fluorine, and chiefly silicates. Pure alumina is a white crystalline powder, or yellowish-white, and amorphous when produced by drying the hydrate, separated chemically from its salts. Alumina is quite unalterable in the fire; the hydrate, however, losing its water at a low red heat. The neutral salts of alumina, with most acids, are insoluble in water. Those soluble in it have an acid reaction upon litmus paper, changing the blue into red.

The sulphates of alumina eliminate water when heated in a glass tube closed at one end. By ignition, sulphurous acid (SO^{2}) is given off, which can be recognized by its smell, and by its acid reaction upon blue litmus paper, when a small strip of it moistened is brought within the orifice of the tube; an infusible residue is left in the tube.

The greater part of the alumina compounds give off water with heat; the most of them are also infusible, except a few phosphates and silicates.

Pure alumina does not fuse with carbonate of soda. The sulphates, when exposed upon charcoal with soda to the reducing flame, leave a hepatic residue. The phosphates melt with a little soda, with a hissing noise, to a semi-transparent mass, but they are infusible with the addition of soda, and give only a tough mass. This is the case, likewise, with the silicates of alumina. Fluoride of aluminium melts with carbonate of soda to a clear bead, spreads by cooling, and appears then milk-white. Borax dissolves the alumina compounds slowly in the oxidizing and reducing flames to a clear bead, which is also clear when cold, or heated intermittingly with a vacillating flame. The bead is turbid, as well in the heat as the cold, when an excess of alumina is present. When the alumina compound is added to excess in the powdered form, the bead appears crystalline upon cooling, and melts again with great difficulty.

Alumina and its compounds are slowly dissolved in the microcosmic salt to a bead, clear in both flames, and when hot or cold. When alumina is added to excess, the undissolved portion appears semi-transparent. Alumina melts with bisulphate of potash into a mass soluble in water. When the powdered alumina compounds are strongly ignited in the oxidizing flame, then moistened with nitrate of cobalt, and re-ignited in the oxidizing flame, an infusible mass is left, which appears, when cooled, of an intense blue color. The presence of colored metallic oxides, in considerable quantity, will alter or suppress this reaction. The silicates of the alkalies produce, in a very strong heat, or continued heat, with nitrate of cobalt, a pale blue color. The blue color produced by alumina is only distinctly visible by daylight; by candle-light it appears of a dirty violet color.

(_b._) _Glucina._ (G^{2}O^{3}).--Glucina only occurs in a few rare minerals, in combination with silica and alumina. It is white and insoluble in the pure state, and its properties generally are similar to those of alumina. The most of its compounds are infusible, and yield water by distillation. Carbonate of soda does not dissolve glucina by ignition. Silicate of glucina melts with carbonate of soda to a colorless globule. Borax and microcosmic salt dissolve glucina and its compounds to a colorless bead which, when overcharged with glucina, or heated with the intermittent flame appears, after cooling, turbid or milk-white. Glucina yields, by ignition with nitrate of cobalt, a black, or dark grey infusible mass.

(_c._) _Yttria_ (YO) occurs only in a few rare minerals, and usually in company with terbium and erbium. Its reactions before the blowpipe are similar to the preceding, but for its detection in compounds it will be necessary to resort to analysis in the wet way.

(_d._) _Zirconia_ (Zr^{2}O^{3}).--This substance resembles alumina in appearance, though it occurs only in a few rare minerals. It is in the pure state infusible, and at a red heat produces such a splendid and vivid white light that the eyes can scarcely endure it. Its other reactions before the blowpipe are analogous to glucina. Microcosmic salt does not dissolve so much zirconia as glucina, and is more prone to give a turbid bead. Zirconia yields with nitrate of cobalt, when ignited, an infusible black mass. To recognize zirconia in compounds we must resort to fluid analysis.

(_e._) _Thorina_ (ThO).--This is the rarest among the rare minerals. In the pure state it is white and infusible, and will not melt with the carbonate of soda. Borax dissolves thorina slowly to a colorless, transparent bead, which will remain so when heated with the intermittent flame. If overcharged with the thorina, the bead presents, on cooling, a milky hue. Microcosmic salt dissolves the thorina very tardily. By ignition with nitrate of cobalt, thorina is converted into an infusible black mass,

CLASS II.

FOURTH GROUP. CERIUM, LANTHANIUM, DIDYMIUM, COLUMBIUM, NIOBIUM, PELOPIUM, TITANIUM, URANIUM, VANADIUM, CHROMIUM, MANGANESE.

The substances of this group cannot be reduced to the metallic state, neither by heating them _per se_, nor by fusing them with reagents. They give by fusion with borax or microcosmic salt, colored beads, while the preceding groups give colorless beads.

(_a._) _Cerium_ (Ce).--This metal occurs in the oxidated state in a few rare minerals, and is associated with lanthanium and didymium, combined with fluorine, phosphoric acid, carbonic acid, silica, etc. When reduced artificially, it forms a grey metallic powder.

(_a._) _Protoxide of Cerium_ (CeO).--It exists in the pure state as the hydrate, and is of a white color. It soon oxidizes and becomes yellow, when placed in contact with the air. When heated in the oxidation flame, it is converted into the sesquioxide, and then is changed into light brick-red color. In the oxidation flame it is dissolved by borax into a clear bead, which appears of an orange or red while hot, but becomes yellow upon cooling. When highly saturated with the metal, or when heated with a fluctuating flame, the bead appears enamelled as when cold. In the reduction flame it is dissolved by borax to a clear yellow bead, which is colorless when cold. If too much of the metal exists in the bead, it then appears enamelled when cooled.

Microcosmic salt dissolves it, in the oxidation flame, to a clear bead, which is colored dark yellow or orange, but loses its color when cold. In the reduction flame the bead is colorless when either hot or cold. Even if highly saturated with the metal, the bead remains colorless when cold. By fusing it with carbonate of soda upon charcoal in the reduction flame, the soda is absorbed by the charcoal, while the protoxide of the metal remains as a light grey powder.

(_B._) _Sesquioxide of Cerium_ (Ce^{2}O^{3}).--This oxide, in the pure state, is a red powder. When heated with hydrochloric acid, it produces chlorine gas, and is dissolved to a salt of the protoxide. It is not affected by either the flame of oxidation or of reduction; when fused with borax or microcosmic salt, it acts like the protoxide. It does not fuse with soda upon charcoal. In the reduction flame it is reduced to the protoxide, which remains of a light grey color, while the soda is absorbed by the charcoal.

(_b._) _Lanthanium_ (La.)--This metal is invariably associated with cerium. It presents, in its metallic state, a dark grey powder, which by compression acquires the metallic lustre.

The _oxide of lanthanium_ (LaO) is white, and its salts are colorless. Heated upon charcoal, it does not change either in the oxidation flame or that of reduction. With borax, in the flame of oxidation or reduction, it gives a clear colorless bead. This bead, if saturated, and when hot, presents a yellow appearance, but is clouded or enamelled when cold. With microcosmic salt the same appearance is indicated. It does not fuse with carbonate of soda, but the soda is absorbed by the charcoal, while the oxide remains of a grey color.

(_c._) _Didymium_ (D).--This metal occurs only in combination with the preceding ones, and it is therefore, like them, a rare one.

_Oxide of Didymium_ (DO).--This oxide is of a brown color, while its salts present a reddish-violet or amethyst color. The oxide is infusible in the oxidation flame, and in that of reduction it loses its brown color and changes to grey. With borax in the oxidation flame, it fuses to a clear dark red or violet bead, which retains its clearness when highly saturated with the oxide, or if heated with a fluctuating flame.

The reactions with microcosmic salt are the same as with borax.

It does not melt with carbonate of soda upon charcoal, but the oxide remains with a grey color, while the soda is absorbed by the charcoal.

(_d._) _Columbium,_ (_Tantalum_--Ta).--This rare metal occurs quite sparingly in the minerals _tantalite_, _yttrotantalite_, etc., as columbic acid. In the metallic state, it presents the appearance of a black powder, which, when compressed, exhibits the metallic lustre. When heated in the air it is oxidized into columbic acid, and is only soluble in hydrofluoric acid, yielding hydrogen. It is oxidized by fusion with carbonate of soda or potash.

_Columbic Acid_ (Ta^{2}O^{3}) is a white powder, and is infusible. When heated in the flame of oxidation or reduction, it appears of a light yellow while hot, but becomes colorless when cold. With borax, in the flames of oxidation and reduction, it fuses to a clear bead, which appears by a certain degree of saturation, of a yellow color so long as it continues hot, but becomes colorless when cold. If overcharged, or heated with an intermittent flame, it presents an enamel white when cool.

It melts with microcosmic salt quite readily in both of the flames, to a clear bead, which appears, if a considerable quantity of columbic acid be present, of a yellow color while hot, but colorless when cold, and does not become clouded if the intermittent flame be applied to it.

With carbonate of soda it fuses with effervescence to a bead which spreads over the charcoal. Melted with more soda, it becomes absorbed by the charcoal.

It yields, moistened with a solution of nitrate of cobalt, and exposed to the oxidation flame after continued blowing, an infusible mass, presenting while hot a light grey color, but after being cooled that of a light red, similar to the color presented by magnesia under the same circumstances. But if there be some alkali mixed with it, a fusion at the edges will be manifest, and it will yield by cooling a bluish-black mass.

(_e._) _Niobium_ (Ni).--This metal occurs as niobic acid in columbite (tantalite). Niobic acid is in its properties similar to columbic acid. It is white and infusible. By heating it either in the flames of reduction or oxidation, it presents as long as it continues hot, a greenish-yellow color, but becomes white when cool. Borax dissolves it in the oxidation flame quite readily to a clear bead, which, with a considerable quantity of niobic acid, is yellow when hot, but transparent and colorless when cold. A saturated bead is clear when either hot or cold, but becomes opaque when heated intermittingly.

In the flame of reduction, borax is capable of dissolving more of the niobic acid, so that a bead overcharged and opaque in the oxidation flame appears quite clear when heated in the flame of reduction. A bead overcharged in the flame of reduction, appears by cooling dim and bluish-grey.

Microcosmic salt dissolves in the flame of oxidation a great quantity of it to a clear bead, which is yellow while hot, but colorless when cold.

In the flame of reduction, and in presence of a considerable quantity of niobic acid, the bead appears while hot of a light dirty blue color, and when cold, of a violet hue; but by the addition of more niobic acid, the bead, when hot, is of a dirty dark blue color, and when cold, of a transparent blue. In the presence of the oxides of iron, the bead is, while hot, of a brownish-red color, but changing when cool to a dark yellow.

This acid fuses with an equal quantity of carbonate of soda upon charcoal, to a bead which spreads very quickly, and is then infusible. When fused with still more soda, it is absorbed.

When moistened with nitrate of cobalt, and heated in the flame of oxidation, it yields an infusible mass which appears grey when hot, and dirty green when cold; but if the heat has been too strong, it is fused a little at the edges, which present a dark bluish-grey color.

_Pelopium_ (Pe).--This metal occurs as an acid in the mineral columbite (tantalite), and is very similar to the two preceding metals.

(_f._) _Pelopic Acid_ (PeO^{3}).--This acid is white, and appears yellow when heated, but resumes its white color when cold. Borax dissolves it in the oxidation flame to a clear colorless bead, which appears, when overcharged and heated intermittingly, enamel-white when cold. This is likewise the case in the flame of reduction, but when overcharged the color is light grey, when the bead is cooled.

Microcosmic salt dissolves it in the flame of oxidation, to a clear yellow bead, which loses its color when cold. In the reduction flame, when the bead is highly saturated, a violet-brown color is produced. In presence of the oxides of iron, the reactions are like those of niobic acid. With carbonate of soda, the reactions are similar to those of niobic acid. By heating with nitrate of cobalt, it yields a light grey infusible mass.

(_g._) _Titanium_ (Ti).--This metal occurs occasionally in the slags of iron works, in the metallic state, as small cubical crystals of a red color. It is a very hard metal, and very infusible. Titanic acid occurs in nature crystallized in _anatase_, _arkansite_, _brookite_, and _rutile_. Titanium is harder than agate, entirely infusible, and loses only a little of its lustre, which can be regained by fusion with borax. It does not melt with carbonate of soda, borax, or microcosmic salt, and is insoluble in every acid except the hydrofluoric. By ignition with saltpetre it is converted into titanic acid, which combines with the potassium, forming the titanate of potassium.

_Titanic Acid_ (TiO^{2}) is white, insoluble, and, when heated, it appears yellow while hot, but resumes upon cooling its white color.

Borax dissolves it in the oxidation flame to a clear yellow bead, which when cool is colorless. When overcharged, or heated with the intermitting flame, it is enamel-white after being cooled. In the reduction flame, the bead appears yellow, if the acid exists in small quantity, but if more be added, then it is of an orange, or dark yellow, or even brown. The saturated bead, when heated intermittingly, appears when cold of an enamelled blue. By addition of the acid, and by heating the bead on charcoal in the reduction flame, it becomes dark yellow while hot, but dark blue, or black and opaque when cold. This bead appears, when heated intermittingly, of a light blue, and when cold, enamelled.

Microcosmic salt fuses with it in the oxidation flame to a clear colorless bead, which appears yellow only in the presence of a quantity of titanic acid, though by cooling it loses its color. In the reduction flame this bead exhibits a yellow color when hot, but is red while cooling, and when cold of a beautiful bluish-violet. If the bead is overcharged, the color becomes so dark that the bead appears opaque, though not presenting an enamel appearance. By heating the bead again in the oxidation flame the color disappears. The addition of some tin promotes the reduction. If the titanic acid contains oxide of iron, or if some is added, the bead appears, when cold, brownish-yellow, or brownish-red.

By fusion with carbonate of soda, titanic acid is dissolved with effervescence to a clear dark yellow bead, which crystallizes by cooling, whereby so much heat is eliminated, that the bead, at the instant of its crystallization, glows with great brightness. A reduction to a metal cannot, however, be effected. By ignition with a solution of nitrate of cobalt in the oxidation flame, it yields an infusible yellowish-green mass.

(_h._) _Uranium_ (U).--This rare metal occurs in the form of protoxide along with other oxides, in the mineral _pitch-blende_; as peroxide in _uranite_ and _uran-mica_, associated with phosphoric acid and lime.

In the metallic state it presents the appearance of a dark grey mass, which is infusible, and remains unchanged when under water, or when exposed to dry air, but, when heated in the oxidation flame, it becomes oxidized, with lively sparkling, to a dark green mass, composed of the protoxide and peroxide.

The _protoxide of uranium_ (UO) is black, uncrystalline, or forms a brown powder. When exposed to heat it is converted partially into peroxide, when it has a dark green color.

The _peroxide of uranium_ (U^{2}O^{3}) is of an orange color, while its hydrate is of a fine yellow color, and in the form of a powder. The salts are yellow.

By heating it in the oxidation flame, it acquires a dark green color, and is partly reduced to protoxide. In the reduction flame it presents a black appearance, and is there completely reduced to protoxide.

Borax dissolves it in the oxidation flame to a clear dark yellow bead, which is colorless when cold, if the metal is not present in great quantity. If more of the metal, or peroxide, be added, the bead changes to orange when hot, and light yellow when cold. When heated with the intermittent flame, it requires a large quantity of the peroxide to produce an enamel appearance in the cooled bead.

In the flame of reduction the bead becomes of a dirty green color, being partly reduced to protoxide, and appears, with a certain degree of saturation, black, when heated intermittingly, but never enamelled. The bead appears on charcoal, and with the addition of tin, of a dark green color.

It fuses with microcosmic salt in the oxidation flame to a clear yellow bead, which is greenish-yellow when cold. In the reduction flame it produces a beautiful green bead, which increases when cold.

When fused upon charcoal with the addition of tin, its color is darker. Carbonate of soda does not dissolve it, although with a very small portion of soda it gives indications of fusion, but with still more of the soda it forms a yellow, or light-brown mass, which is absorbed by the charcoal, but it is not reduced to the metallic state.

(_i._) _Vanadium_ (V).--This very rare mineral is found in small quantity in iron-ores, in Sweden, and as vanadic acid in a few rare minerals. The metal presents the appearance of an iron-grey powder, and sometimes that of a silver-white mass. It is not oxidized either by air or water, and is infusible.

_Vanadic Acid_ (VO^{3}) fuses upon platinum foil to a deep orange liquid, which becomes crystalline after cooling. When fused upon charcoal, one part of it is absorbed, while the rest remains upon the charcoal and is reduced to protoxide similar in appearance to graphite.

A small portion of it fuses with borax in the oxidation flame to a clear colorless bead, which appears, with the addition of more vanadic acid, of a yellow color, but changes to green when cold.

In the reduction flame the bead is brown while hot, but changes, upon cooling, to a beautiful sapphire-green. At the moment of crystallization, and at a degree of heat by which at daylight no glowing of the heated mass is visible it begins to glow again. The glow spreads from the periphery to the centre of the mass, and is caused by the heat liberated by the sudden crystallization of the mass. It now exhibits an orange color, and is composed of needle crystals in a compact mass.

Microcosmic salt and vanadic acid fuse in the oxidation flame to a dark yellow bead which, upon cooling, loses much of its color.

In the reduction flame the bead is brown while hot, but, upon cooling, acquires a beautiful green color.

Vanadic acid fuses with carbonate of soda upon charcoal, and is absorbed.

(_k._) _Chromium_ (Cr) occurs in the metallic state only in a very small quantity in meteoric iron, but is frequently found in union with oxygen, as oxide in chrome iron ore, and as chromic acid in some lead ores.

In the metallic state it is of a light grey color, with but little metallic lustre, very hard, and not very fusible. Acids do not act upon it, except the hydrofluoric; fused with nitre, it forms chromate of potassa. It is unaltered in the blowpipe flame.

_Sesquioxide of Chromium_ (Cr^{2}O^{3}).--This oxide forms black crystals of great hardness, and is sometimes seen as a green powder. Its hydrate (Cr^{2}O^{3} + 6HO) is of a bluish-grey color. It forms with acids two classes of isomeric salts, some of which are of a green color, and the others violet-red or amethyst. The neutral and soluble salts have an acid reaction upon blue litmus paper, and are decomposed by ignition.

Sesquioxide of chromium in the oxidation and reduction flames is unchangable. When exposed to heat, the hydrate loses its water, and gives a peculiarly beautiful flame. In the oxidation flame borax dissolves the sesquioxide of chromium slowly to a yellow bead (chromic acid) which is yellowish green when cold. Upon the addition of more of the oxide, the bead is dark red while hot, but changes to green as it becomes cold.

In the reduction flame the bead is of a beautiful green color, both while hot and when cold. It is here distinguished from vanadic acid, which gives a brownish or yellow bead while hot.

With microcosmic salt it fuses in the oxidation flame to a clear yellow bead, which appears, as it cools, of a dirty-green, color, but upon being cool is of a fine green color. If there be a superabundance of the oxide, so that the microcosmic salt cannot dissolve it, the bead swells up, and is converted into a foamy mass, in consequence of the development of gases.

In the reduction flame it fuses to a fine green bead. The addition of a little tin renders the green still deeper.

Sesquioxide of chromium fuses with carbonate of soda upon platinum foil to a brown or yellow bead, which, upon cooling, appears of a lighter color and transparent (chromate of sodium).

When fused with soda upon charcoal, the soda is absorbed, and the green oxide is left upon it, but is never reduced to the metallic state.

_Chromic Acid_ (CrO^{3}) crystallizes in the form of deep ruby red needles. It is decomposed into sesquioxide and oxygen when heated. This decomposition is attended with a very lively emission of light, but this is not the case if the chromic acid has been attained by the coöperation of an aqueous solution, unless the reduction is effected in the vapor of ammonia. Before the blowpipe chromic acid produces the same reactions as the sesquioxide.

(_l._) _Manganese_ (Mn).--This metal occurs in considerable abundance, principally as oxides, less frequently as salts, and sometimes in combination with sulphur and arsenic. It is found in plants, and passes with them into the animal body. In the metallic state, it is found frequently in cast iron and steel. It is a hard, brittle metal, fusible with difficulty, and of a light grey color. It tarnishes upon exposure to the air and under water, and falls into a powder.

_Protoxide of Manganese_ exists as a green powder; as hydrate separated by caustic alkalies, it is white, but oxidizes very speedily upon exposure to the air. The protoxide is the base of the salts of manganese. These salts, which are soluble in water, are decomposed when heated in the presence of the air--except the sulphate (MnO, SO^{3}), but if the latter is exposed to ignition for awhile, it then ceases to be soluble in water, or at least only sparingly so.

_Sesquioxide of Manganese_ (Mn^{2}O^{3}) Occurs very sparingly in nature as small black crystals (_Braunite_) which give, when ground, a brown powder. When prepared by chemical process, it is in the form of a black powder. The hydrate occurs sometimes in nature as black crystals (_manganite_). By digestion with acids, it is dissolved into salts of the protoxide. With hydrochloric acid, it yields chlorine.

The _prot-sesquioxide of manganese_ (MnO + Mn^{2}O^{3}) occurs sometimes in black _crystals_ (_hausmannite_). Prepared artificially, it is in the form of a brown powder.

_Peroxide of Manganese_ (MnO^{2}) occurs in considerable abundance as a soft black amorphous mass, or crystallized as pyrolusite, also reniform and fibrous. It is deprived of a part of its oxygen when exposed to ignition. It eliminates a considerable quantity of chlorine from hydrochloric acid, and is thereby converted into chloride of manganese (ClMn).

Most of the manganese compounds which occur in nature yield water when heated in a glass tube closed at one end. The sesquioxide and peroxide give out oxygen when strongly heated, which can be readily detected by the increased glow which it causes, if a piece of lighted wood or paper is brought to the mouth of the tube. The residue left in the tube is a brown mass (MnO + Mn^{2}O^{3}).

When exposed to ignition with free access of air, all manganese oxides are converted into (MnO + Mn^{2}O^{3}), but without fusion. Such, at least, is the statement of some of the German chemists, although it will admit perhaps of further investigation.

Manganese oxides fuse with borax in the oxidation flame to a clear and intensely colored bead, of a violet hue while hot, but changing to red as it cools. If a considerable quantity of the oxide is added, the bead acquires a color so dark as to become opaque. If such be the case, we have to press it flat, by which its proper color will become manifest.

In the reduction flame the bead is colorless. A very dark colored bead must be fused upon charcoal with the addition of some tin. The bead must be cooled very suddenly, for if it cools too slowly, it then has time to oxidize again. This may be effected by pushing it off the platinum wire, or the charcoal, and pressing it flat with the forceps.

The oxides of manganese fuse with microcosmic salt in the oxidation flame, to a clear brownish-violet bead, which appears reddish-violet while cooling. This bead does not become opaque when overcharged with manganese. As long as it is kept in fusion a continued boiling or effervescence takes place, produced by the expulsion of oxygen, in consequence of the fact that the microcosmic salt cannot dissolve much sesquioxide, while the rest is reduced to protoxide, is re-oxidated, and instantly again reduced. If the manganese is present in such a minute quantity as not to perceptibly tinge the bead, the color may be made to appear by the contact of a crystal of nitre while hot. The bead foams up upon the addition of the nitre, and the foam appears, after cooling, of a rose-red or violet color. In the reduction flame the bead sometimes becomes colorless.

The oxides of manganese fuse with carbonate of soda upon platinum foil or wire, to a clear green bead, which appears bluish-green and partially opaque when cold (manganate of soda NaO + MnO^{3}). A very minute trace of manganese will produce this green color. The oxides of manganese cannot be reduced upon charcoal with carbonate of soda before the blowpipe. The soda is absorbed, and (MnO + Mn^{2}O^{3}) is left.

GROUP FIFTH.--IRON, COBALT, NICKEL.

The oxides of this group are reduced to the metallic state when fused with carbonate of soda upon charcoal in the reduction flame. Metals when thus reduced form powders, are not fusible or volatile in the blowpipe flame, but they are attracted by the magnet.

Furthermore, these oxides are not dissolved by carbonate of soda in the oxidation flame, but they produce colored beads with borax and microcosmic salt.

(_a._) _Iron._--It occurs in great abundance in nature. It is found in several places in America in the metallic state, and it likewise occurs in the same state in meteors. It occurs chiefly as the oxide (red hematite, brown hematite, magnetic oxide, etc.), and frequently in combination with sulphur. Iron also forms a constituent of the blood.

Metallic iron is of a grey color, and presents the metallic lustre vividly when polished. It is very ductile, malleable, and tenacious. It is very hard at common temperatures, but soft and yielding at a red heat.

In dry and cold air, iron does not oxidize, but when the air is dry and moist, it oxidizes rapidly. This likewise takes place with great rapidity when the metal is heated to redness. When submitted to a white heat iron burns with brilliant scintillations.

_Protoxide of Iron_ (FeO).--This oxide does not occur pure in nature, but in union with the peroxide of iron and other substances. It presents the form of a black powder, and has some metallic lustre, is brittle, and fuses at a high temperature to a vitreous looking mass. It is attracted by the magnet, and of course is susceptible of becoming magnetic itself. It forms with water a hydrate, but this passes so rapidly into a state of higher oxidation, that it is difficult to keep it in the pure state.

_Magnetic Oxide of Iron_ (FeO + Fe^{2}O^{3}).--This peculiar oxide is of a dark color, and is magnetic, so that tacks or small nails adhere to it when brought in contact with it. It is the variety of the oxide termed "loadstone." It is found frequently crystallized in octahedrons in Scandinavia and other places. Magnetic oxide of iron is produced when red-hot iron is hammered.

_Sesquioxide of Iron_ (Fe^{2}O^{3}).--This oxide is found native in great abundance as red hematite and specular iron, crystallized in the rhombic form. In the crystalline state it is of a blackish-grey color, and possessed of the metallic lustre. When powdered, it forms a brownish-red mass. When artificially prepared, it presents the appearance of a blood-red powder. It is not magnetic, and has less affinity for acids than the protoxide. Its hydrate is found native as brown hematite.

By exposing the peroxide of iron to the oxidation flame, it is not acted upon, but in the reduction flame it becomes reduced to the magnetic oxide.

The oxides of iron are dissolved by borax in the oxidation flame to a clear dark-yellow or dark-red bead, which appears lighter while cooling, and yellowish when cold. In the presence of a very small quantity of iron, the bead appears colorless when cold. If the iron is increased, the bead is opaque while cooling, and of a dirty dark-yellow color when cold. In the reduction flame, and fused upon platinum wire, the bead appears dark green (FeO + Fe^{2}O^{3}). By the addition of some tin, and fused upon charcoal, the bead appears bluish-green, or not unlike that of sulphate of iron.

Microcosmic salt dissolves the oxides of iron in the oxidation flame to a clear bead, which, by the addition of a considerable quantity of iron, becomes of an orange color while hot, but gets lighter while cooling, presenting finally a greenish hue, and gradually becoming lighter, till, when cold, it is colorless. If the iron is increased, the hot bead presents a dark red color, but while cooling a brownish-red, which changes to a dirty-green, and, when cold, to a brownish-red color. The decrease of the color during the transition from the hot to the cold state is still greater in the bead formed by the microcosmic salt.

In the reduction flame no change is visible if the quantity of iron be small. By the addition of more iron, the hot bead appears red, and while cooling, changes to yellow, then green, and, when cold, is of a dull red. By fusing the bead on charcoal with a small addition of tin, it exhibits, while cooling, a bluish-green color, but, when cold, is colorless.

The oxides of iron are not dissolved in the oxidation flame by fusion with carbonate of soda. By ignition with soda upon charcoal in the reduction flame, they are absorbed and reduced to the metallic state. Cut out this portion of the charcoal; grind it with the addition of some water in an agate mortar, for the purpose of washing off the carbon particles, when the iron will remain as a grey magnetic powder.

(_b._) _Cobalt_ (Co) occurs in combination with arsenic and sulphur, and associated with nickel and iron. It is found occasionally in combination with selenium, and there are a traces of it in meteoric iron. In the metallic state it is of a light, reddish-grey color, rather brittle, and only fusible at a strong white heat; at common temperatures it is unalterable by air or water. At a red heat, it oxidizes slowly and decomposes water; at a white heat it burns with a red flame. Cobalt is soluble in dilute sulphuric or hydrochloric acid by the aid of heat, whereby hydrogen is eliminated. These solutions have a fine red color.

_Protoxide of Cobalt_ (CoO).--It is an olive-green powder, but, by exposure to the air, it becomes gradually brown. Its hydrate is a rich red powder. The solution of its salts is red, but the aqueous solution is often blue.

When heated in the oxidation flame, the protoxide is converted into the black proto-sesquioxide (CoO + Co^{2}O^{3}). In the reduction flame it shrinks and is reduced without fusion to the metallic state. It is now attracted by the magnet and acquires lustre by compression.

Borax dissolves it in the oxidation flame, and produces a clear, intensely colored blue bead, which remains transparent and of the same beautiful blue when cold. This blue is likewise manifest even if the bead be heated intermittingly. If the cobalt exists in considerable quantity, the color of the bead is so intense as to appear almost black.

This reaction of cobalt is so characteristic and sensitive that it can detect a minute trace.

With microcosmic salt the same reaction is exhibited, but not so sensitive, nor is the bead so intensely colored when cold as that with borax.

By fusion with carbonate of soda upon a platinum wire, with a very small portion of cobalt, a bright red colored mass is produced which appears grey, or slightly green when cold. By fusion upon platinum foil the fused portion floats down from the sides, and the foil is coated around the undissolved part, with a thin, dark-red sublimate. When fused upon charcoal, and in the reduction flame, it is reduced with soda to a grey powder, which is attracted by the magnet, and exhibits the metallic lustre by compression.

_Sesquioxide of Cobalt_ (Co^{2}O^{3}).--It is a dark brown powder. Its hydrate (2HO + Co^{2}O^{3}) is a brown powder. It is soluble only in acetic acid as the acetate of the sesquioxide. All other acids dissolve its salts to protoxide, the hydrochloric acid producing chloric gas. By ignition in the oxidation flame, it is converted into the proto-sesquioxide (CoO + Co^{2}O^{3}) and produces with reagents before the blowpipe the same reactions as the protoxide.

(_c._) _Nickel_ (Ni).--This metal occurs invariably associated with cobalt, and in analogous combinations, chiefly as the arsenical nickel. In the metallic state it is greyish, silver-white, has a high lustre, is hard, and malleable both cold and hot. At common temperatures, it is unalterable either in dry or moist air. When ignited, it tarnishes. It is easily dissolved by nitric acid, but very slowly by dilute sulphuric or hydrochloric acid, producing hydrogen.

_Protoxide of Nickel _(NiO).--It is in the form of small greyish-black octahedrons, or a dark, greenish-grey powder. Its hydrate is a green powder. Both are unalterable in the air, and are soluble in nitric, sulphuric, and hydrochloric acids, to a green liquid. The protoxide is the base of the salts of nickel, which in the anhydrous state are yellow, and when hydrated are green. The soluble neutral salts change blue litmus paper to red. By ignition in the oxidation flame, protoxide of nickel is unaltered. In the reduction flame and upon charcoal, it becomes reduced, and forms a grey adherent powder, which is infusible, and presents the metallic lustre by compression, and is magnetic. Borax dissolves it in the oxidation flame very readily to a clear bead, of a reddish-violet or dark yellow color, but yellow or light red when cold. If there is but a small quantity of the oxide present, it is colorless. If more of the oxide be present, the bead is opaque and dark brown, and appears, while cooling, transparent and dark red. By the addition of a salt of potassa (the nitrate or carbonate) a blue or a dark purple colored bead is produced. The borax bead, in the reduction flame, is grey, turbid, or completely opaque from the reduced metallic particles. After a continued blast, the bead becomes colorless, although the particles are not fused. If the nickel contains cobalt, it will now be visible with its peculiar blue color. Upon charcoal, and by the addition of some tin, the reduction of the oxide of nickel is easily effected, while the reduced nickel fuses with the tin.

The oxide of nickel is dissolved by microcosmic salt in the oxidation flame to a clear bead, which appears reddish while hot, but yellow and sometimes colorless when cooling. If a considerable quantity of nickel be present the heated bead is of a brown color, but orange when cooled. In the reduction flame, and upon platinum wire, the color of the bead is orange when cold; but upon charcoal, and with the addition of a little tin, the bead appears grey and opaque. After being submitted to the blowpipe flame all the nickel is reduced, and the bead becomes colorless.

Carbonate of soda does not affect it in the oxidation flame, but in the reduction flame and upon charcoal, it is absorbed and reduced, and remains, after washing off the carbon, as a white metallic powder, which is infusible, and has a greater attraction for the magnet than iron.

_Sesquioxide of Nickel_ (Ni^{2}O^{3}).--It is in the form of a black powder, and does not combine with other substances, unless it is reduced to the protoxide. It exhibits before the blowpipe the same behavior as the protoxide.

GROUP SIXTH.--ZINC, CADMIUM, ANTIMONY, TELLURIUM.

The substances of this group can be reduced upon charcoal by fusion with carbonate of soda, but the reduced metals are volatilized, and cover the charcoal with sublimates.

(_a._) _Zinc_ (Zn).--This metal is found in considerable abundance, but never occurs in the pure metallic state, but in combination with other substances, chiefly as sulphide in zinc blende, as carbonate in calamine, and as the silicate in the kieselzinc ore; also, with sulphuric acid, the "vitriol of zinc."

Zinc is of a bluish-white color and metallic lustre, is crystalline and brittle when heated 400°F., but malleable and ductile between 200° and 300°. It will not oxidize in dry air, but tarnishes if exposed to air containing moisture, first becomes grey, and then passes into the white carbonate. It decomposes in water at a glowing heat. It is dissolved by diluted acids, while hydrogen is eliminated. It melts at about 775°, and distills when exposed to a white heat in a close vessel. When heated over 1000° in the open air, it takes fire, and burns with a bluish-white light, and with a thick white smoke of oxide of zinc.

_Oxide of Zinc_ (ZnO).--In the pure state, oxide of zinc is a white powder, infusible, and not volatile. It is readily soluble in acids after being heated strongly. Its soluble neutral salts, when dissolved in water, change blue litmus paper to red. Its salts, with organic acids, are decomposed by ignition, and the carbonate of zinc remains.

The oxide of zinc turns yellow by being ignited in the oxidation flame, but it is only visible by daylight; this color changes to white when cold. It does not melt, but produces a strong light, and it is not volatile.

It disappears gradually in the flame of reduction, while a white smoke sublimates upon the charcoal. This sublimate is yellow while hot, but changes to white when cold. The cause of this is, that the oxide is reduced, is volatilized, and re-oxidized, by going through the external flame in the form of a metallic vapor.

Borax dissolves oxide of zinc in the flame of oxidation easily to a clear bead, which is yellow while hot, and colorless when cold. The bead becomes, by the addition of more oxide, enamelled, while cooling. If the bead is heated with the intermittent flame, it is milk-white when cold. When heated in the flame of reduction upon platinum wire, the bead at first appears opaque, and of a greyish color, but becomes clear again after a continued blast.

When heated upon charcoal in the reduction flame, it is reduced to a metal; but, at the same moment, is volatilized, and sublimes as oxide of zinc upon the charcoal, about one line's distance from the assay. This is likewise the case with the microcosmic salt, except that it is more easily volatilized in the reduction flame.

Carbonate of soda does not dissolve the oxide of zinc in the flame of oxidation. In the reduction flame and upon charcoal, the oxide of zinc is reduced to the metallic state, and is volatilized with a white vapor of the zinc oxide, which sublimes on the charcoal and exhibits a yellow color while hot, and which changes to white when cold. By a strong heat the reduced zinc burns with a white flame.

Moistened with a solution of cobalt oxide, and heated strongly in the flame of oxidation, zinc oxide becomes of a yellowish-green color while hot, and changes to a beautiful green color when cold.

(_b._) _Cadmium_ (Cd).--This is one of the rare metals. It occurs in combination with sulphur in _greenockite_, and in some ores of zinc. It was detected first in the year 1818, and presents itself as a tin-white metal of great lustre, and susceptible of a fine polish. It has a fibrous structure, crystallizes easily in regular octahedrons, presenting often the peculiar arborescent appearance of the fern. It is soft, but harder and more tenacious than tin; it can be bent, filed, and easily cut: it imparts to paper a color like that of lead. It is very malleable and ductile, and can be hammered into thin leaves. It is easily fused, and melts before it glows (450°). At a temperature not much over the boiling point of mercury, it begins to boil, and distills, the vapor of the metal possessing no peculiar odor. It is unalterable in the air for a long time, but at length it tarnishes and presents a greyish-white, half metallic color. This metal easily takes fire when heated in the air, and burns with a brownish-yellow vapor, while it deposits a yellow sublimate upon surrounding bodies. It is easily soluble in acids with the escape of hydrogen, the solutions being colorless. Its salts, soluble in water, are decomposed by ignition in free air. Its soluble neutral salts change blue litmus paper to red. The salts, insoluble in water, are readily dissolved in acids.

_Oxide of Cadmium_ (CdO).--This oxide is of a dark orange color. It does not melt, and is not volatile, not even at a very high temperature. Its hydrate is white, loses in the heat its hydratic water, and absorbs carbonic acid from the air when it is kept in open vessels.

Cadmium oxide is unaltered when exposed upon platinum wire in the flame of oxidation. When heated upon charcoal in the flame of reduction it disappears in a very short time, while the charcoal is coated with a dark orange or yellow powder, the color of which is more visible after it is cooled. The portions of this sublimate furthest from the assay present a visible iridescent appearance. This reaction of cadmium is so characteristic and sensitive that minerals (for instance, calamine, carbonate of zinc) which contains from one to five per cent. of carbonate of cadmium, will give a dark yellowish ring of cadmium oxide, a little distance from the assay, after being exposed for a few moments to the flame of reduction. This sublimate is more visible when cold, and is produced some time previous to the reduction of the zinc oxide. If a vapor of the latter should appear, it indicates that it has been exposed too great a length of time to the flame.

Borax dissolves a considerable quantity of cadmium oxide upon a platinum wire to a clear yellow bead, which, when cold, is almost colorless. If the bead is nearly saturated with the cadmium oxide, it appears milk-white when intermittingly heated. If the bead is completely saturated, it retains its opalescent appearance. Upon charcoal, and in the flame of reduction, the bead intumesces, the cadmium oxide becomes reduced to metal; this becomes volatilized and re-oxidized, and sublimes upon the charcoal as the yellow cadmium oxide.

In the oxidation flame, microcosmic salt dissolves a large quantity of it to a clear bead, which, when highly saturated and while hot, is yellowish colored, but colorless when cold. By complete saturation, the bead is enamel-white when cold.

Upon charcoal, in the flame of reduction, the bead is slowly and only partially reduced, a scanty sublimate being produced on the charcoal. The addition of tin promotes the reduction.

Carbonate of soda does not dissolve cadmium oxide in the oxidation flame. In the reduction flame, upon charcoal, it is reduced to metal, and is volatilized to a red-brown or dark, red sublimate of cadmium oxide upon the charcoal, at a little distance from the assay the charcoal presenting the characteristic iridescent appearance. This reaction is still more sensitive if the cadmium oxide is heated _per se_ in the reduction flame.

_Antimony_ (Sb).--This metal is found in almost every country. It principally occurs as the tersulphide (SbS^{3}), either pure or combined with other sulphides, particularly with basic sulphides. Sometimes it occurs as the pure metal, and rarer in a state of oxidation as an antimonious acid and as the oxysulphide.

In the pure state, antimony has a silver-white color, with much lustre, and presents a crystalline structure. The commercial and impure metal is of a tin-white color, and may frequently be split in parallel strata. It is brittle and easily pulverized. It melts at a low red heat (810°), is volatilized at a white heat, and can be distilled. At common temperatures it is not affected by the air. At a glowing heat it takes fire, and burns with a white flame, and with white fumes, forming volatile antimonious acid. Common acids oxidize antimony, but dissolve it slightly. It is soluble in aqua regia (nitro-hydrochloric acid).

_Sesquioxide of Antimony_ (Sb^{2}O^{3}).--In the pure state this oxide is a white powder, is fusible at a dull red heat to a yellow liquid, which, after cooling, is greyish-white and crystalline. If it is heated excluded from the air, it can be volatilized completely; it sublimes in bright crystals having the form of needles. It occurs sometimes in nature as white and very bright crystals. It takes fire when heated in the open air, and burns with a white vapor to antimonious acid. It fuses with the ter-sulphide of antimony to a red bead. It is distinguished from the other oxides of antimony by the readiness with which it is reduced to the metallic state upon charcoal, and by its easy fusibility and volatility.

The sesquioxide is the base of some salts--for instance, the tartar emetic. It is not soluble in nitric acid, but is soluble in hydrochloric acid. This solution becomes milky by the addition of water. A part of the salts of the sesquioxide of antimony are decomposed by ignition. The haloid salts are easily volatilized, without decomposition. Its soluble neutral salts change blue litmus paper to red, and are converted, by admixture of water, into insoluble basic and soluble acid salts.

Antimonious acid (antimoniate of sesquioxide of antimony, Sb^{2}O^{3} + Sb^{2}O^{5}) is of a white color, but, when heated, of a light yellow color, but changes to white again when cold. It is infusible and unaltered by heat. It forms a white hydrate, and both are insoluble in water and nitric acid. It is partly soluble in hydrochloric acid, with the application of heat. The addition of water causes a precipitate in this solution.

_Antimonic Acid _(Sb^{2}O^{5}).--In the pure state this acid is a light yellow-colored powder. Its hydrate is white, and is insoluble in water and nitric acid. It is sparingly soluble in hot concentrated hydrochloric acid. It forms salts with every base, some of which are insoluble, and others sparingly so. Notwithstanding that antimonic acid is insoluble in water, it expels the carbonic acid from the solutions of the carbonates of the alkalies. Antimonic acid and its hydrate changes moistened blue litmus paper to red.

_Behavior of Antimony and its Oxides before the Blowpipe._

_Metallic Antimony_ fuses easily upon charcoal. When heated to glowing, and then removed from the flame, it continues to glow for awhile, and produces a thick white smoke. The vapor crystallizes gradually, and coats the assay with small crystals which iridesce like mother of pearl (sesquioxide of antimony). It is not volatile at the temperature of melted glass. Ignited in an open glass tube, it burns slowly with a white vapor, which condenses upon the cool part of the tube, and exhibits some indications of crystallization. This vapor consists of the sesquioxide, and can be driven by heat from one place to another, without leaving a residue. If the metallic antimony contains sulphide of antimony, there is a corresponding portion of antimonious acid produced, which remains as a white sublimate after the sesquioxide is removed.

_Sesquioxide of antimony_ melts easily, and sublimes as a white vapor. It may be prepared by precipitating and drying. When heated, it takes fire previous to melting, glows like tinder, and is converted into antimonious acid, which is now infusible. When heated upon charcoal in the flame of reduction, it is reduced to the metallic state, and partly volatilized. A white vapor sublimates upon the charcoal, while the external flame exhibits a greenish-blue color. Antimonious acid is infusible, produces a strong light, and is diminished in volume when heated in the external flame, during which time a dense white vapor sublimes upon the charcoal. It is not, however, in this manner reduced to the metallic state like the sesquioxide.

_Antimonic acid_, when first heated, becomes white, and is converted into antimonious acid. Hydrated antimonic acid, which is originally white, appears at first yellow while giving off water, and then becomes white again, while oxygen is expelled, and it is converted into antimonious acid.

The oxides of antimony produce, with blowpipe reagents, the following reactions: borax dissolves oxides of antimony in the oxidation flame in considerable quantity to a clear bead, which is yellow while hot, but colorless when cold. If the bead is saturated, a part of the oxide is volatilized as a white vapor. Upon charcoal, in the oxidation flame, it is completely volatilized, and the charcoal is covered with a white sublimate. Heated upon charcoal in the reducing flame, the bead is of a greyish color, and partially, if not wholly opaque, from the presence of reduced metallic particles. A continued heat will volatilize them, and the bead becomes clear. The addition of tin promotes the reduction.

Microcosmic salt dissolves the compounds of antimony in the flame of oxidation with intumescence, to a clear light-yellow colored bead, which when cold is colorless. Heated upon charcoal in the reduction flame, the bead is first turbid, but soon becomes transparent. The addition of tin renders the bead greyish while cooling, but a continued blast renders it transparent. Soda dissolves the compounds of antimony upon platinum wire in the oxidation flame, to a clear colorless bead, which is white when cold.

Upon charcoal, both in the oxidation and reduction flames, the antimony compounds are readily reduced to the metal, which is immediately volatilized, and produces a white incrustation of oxide of antimony upon the charcoal. If the antimony compounds are heated upon charcoal in the flame of reduction, with a mixture of carbonate of soda and cyanide of potassium (KCy), there are produced small globules of metallic antimony. At the same time, a part of the reduced metal is volatilized (this continues after the assay is removed from the flame) and re-oxidized. A white incrustation appears upon the charcoal, and the metallic globules are covered with small white crystals. If this white sublimate upon the charcoal is moistened with a solution of cobalt-oxide, and exposed to the reduction flame, a part of it is volatilized, while the other part passes into higher oxidation, and remains, after cooling, of a dirty dark-green color.

(_d._) _Tellurium_ (Te).--This is one of the rare metals. It occurs very seldom in the metallic state, but often with bismuth, lead, silver, and gold. Tellurium, in the pure state, is silver-white, very bright, of a foliated or lamellar structure, brittle, and easily triturated. It is inclined to crystallize. It is soluble in concentrated sulphuric acid without oxidation. The solution is of a fine purple color, and gives a precipitate with the addition of water.

_Tellurium in the Metallic form._--By the aid of heat it is oxidized in sulphuric acid, a portion of the oxygen of the acid oxidizing the metal, while sulphurous acid gas escapes. This solution is colorless, and is tellurous acid, dissolved in sulphuric acid. It melts at a low red heat, and volatilizes at a higher temperature. If tellurium is heated with free access of air, it takes fire, and burns with a blue color, the flame being greenish at the edges, while a thick white vapor escapes, which has a feeble acidulous odor.

_Tellurous Acid_ (TeO^{2}) is of a fine, granulous, crystalline or white earthy mass, which is partly soluble in water. The solution has a strong metallic taste, and an acid reaction upon litmus paper. Heated in a tube closed at one end until it begins to glow, it fuses to a yellow liquid which is colorless, crystalline, and opaque when cold. Beads of it remain usually transparent like glass. Heated upon platinum wire in the flame of oxidation, it melts, and is volatilized as a white vapor. When heated upon charcoal in the oxidation flame, it melts, and is reduced to the metallic state, but volatilizes and a sublimate of white tellurous acid is formed upon the charcoal. The edge of this deposit is usually red or dark-yellow.

Heated upon charcoal in the flame of reduction, it is rapidly reduced, the external flame exhibiting a bluish-green color.

Borax dissolves it in the oxidation flame upon platinum wire to a clear colorless bead which turns grey when heated upon charcoal, through the presence of reduced metallic particles. Upon charcoal, in the reduction flame, the bead is grey, caused by the reduced metal. After a continued blast, tellurium is completely volatilized, and the bead appears clear again, while a white sublimate is deposited upon the charcoal.

With microcosmic salt, the same reactions are produced.

With carbonate of soda, tellurous acid fuses upon platinum wire to a clear colorless bead, which is white when cold. Upon charcoal it is reduced, and forms _tellur-sodium_, which is absorbed by the charcoal, and metallic tellurium, which is volatilized, and deposits upon the charcoal a white incrustation (tellurous acid).

If tellurous acid, finely powdered charcoal, and carbonate of soda are mixed together, and the mixture be well ignited in a closed tube, until fusion is effected, and a few drops of boiled water are brought into the tube, they are colored purple, indicating the presence of _tellur-sodium._

_Telluric Acid _(TeO^{3}) forms six-sided prismatic crystals. It has not an acid, but rather a metallic taste. It changes blue litmus paper to red; is slowly soluble in water, and rather sparingly. Exposed to a high temperature, but not until glowing, the crystalline acid loses its water, and acquires an orange color, but still it preserves its crystalline form, although no longer soluble in water, and is in fact so much changed in its properties as to present the instance of an isomeric modification.

If telluric acid is heated gently in a closed tube, it loses water and turns yellow. Heated still more strongly, it becomes milk-white, oxygen is expelled, and it is converted into tellurous acid. The presence of oxygen can be recognized by the more lively combustion which an ignited splinter of wood undergoes when held in it. Telluric acid produces the same reactions with the blowpipe reagents as tellurous acid.

SEVENTH GROUP.--LEAD, BISMUTH, TIN.

The oxides of these metals are also reduced to the metallic state by fusion with soda upon charcoal in the flame of reduction, but they are volatilized only after a continued blast, and a sublimate is thrown upon the charcoal.

(_a._) _Lead_ (Pb).--This metal occurs in considerable quantity in nature, chiefly as galena or lead-glance (sulphide of lead). Likewise, but more rarely, as a carbonate; also as a sulphate, and sometimes combined with other acids and metals.

In the metallic state, lead is of a bluish-grey color, high lustre, and sp. gr. 11.4. It is soft, and communicates a stain to paper. It is malleable, ductile, but has very little tenacity. It melts at about 612°. Exposed to the air it soon tarnishes, being covered with a grey matter, which some regard as a suboxide (Pb^{2}O), and others as simply a mixture of lead and protoxide. At a glowing heat it is oxidized to a protoxide, and at a white heat it is volatilized. It is insoluble in most acids. It is, however, soluble in nitric acid, but without decomposing water.

(_L._) _Protoxide of Lead_ (PbO).--It is an orange-colored powder, which melts at a glowing temperature, and forms a lamellar mass after cooling. Protoxide of lead absorbs oxygen from the atmosphere while melting, which is given off again by cooling. Being exposed for a longer while to the air, it absorbs carbonic acid and water, and becomes white on the surface. It is soluble in nitric acid and caustic alkalies. It forms with most acids insoluble salts. It is slightly soluble in pure water, but not in water which contains alkaline salts. This hydrate is white.

([beta].) _Red Oxide of Lead_ (PbO^{2}, PbO).--It forms a puce-colored powder. It is insoluble in caustic alkalies. Hydrochloric acid dissolves it and forms a yellow liquid, which is soon decomposed into chloride of lead and chlorine. It is reduced by ignition to the protoxide.

([gamma].) _Peroxide of Lead _(PbO^{2}).--It is a dark-brown powder. It yields with hydrochloric acid the chloride of lead and chlorine gas. When heated it liberates oxygen, and is reduced to the protoxide.

Lead combinations give the following reactions before the blowpipe: Metallic lead tarnishes when heated in the oxidation flame, and is instantly covered with a grey matter, consisting of the protoxide and the metal. It fuses quickly, and is then covered with a yellowish-brown protoxide until all the lead is converted into the protoxide, which melts to a yellow liquid. In the reduction flame and upon charcoal, it is volatilized, while the charcoal becomes covered with a yellow sublimate of oxide. A little distance from the assay, this sublimate appears white (carbonate of lead). Protoxide of lead melts in the flame of oxidation to a beautiful dark yellow bead. In the flame of reduction, and upon charcoal, it is reduced with intumescence to metallic lead, which is volatilized by a continued blast, and sublimates on charcoal, as mentioned above.

Red oxide of lead turns black when heated in the glass tube closed at one end, and liberates oxygen, which is easily detected by the introduction of an ignited splinter, when a more lively combustion of the wood proves the presence of uncombined oxygen. The red oxide in this case is reduced to the protoxide. Heated upon platinum foil, it first turns black, is reduced to the protoxide, and melts into a dark yellow liquid. In the reduction flame, upon charcoal, it is reduced to the metal with intumescence. After a continued blast, a yellow sublimate of protoxide is produced upon the charcoal, and at a little distance off, around this sublimate, a white one of carbonate of lead is produced. This sublimate disappears when touched by the flame of reduction, while it communicates an azure blue-tinge to the external flame. This is likewise the case with the peroxide of lead.

The different oxides of lead produce with the blowpipe reagents the same reactions.

_Borax_ dissolves lead compounds with the greatest readiness upon platinum wire in the oxidation flame to a transparent bead, which is yellow when hot, but colorless after being cooled. With the addition of more of the lead oxide, it becomes opalescent. When heated by the intermittent flame, and with still more of the oxide, it acquires a yellow enamel after cooling. Heated upon charcoal, in the flame of reduction, the bead spreads and becomes opaque. After a continued blast, all the oxide is reduced with effervescence to metallic lead, which melts and runs towards the edges of the bead, while the bead again becomes transparent.

_Microcosmic Salt_ dissolves oxides of lead upon platinum wire in the flame of oxidation easily to a clear, colorless bead, which appears, when highly saturated, yellow while hot. A saturated bead becomes enamel-like after cooling. The bead appears in the flame of reduction, and upon charcoal, of a greyish color and dull. By the addition of more oxide, a yellow sublimate of protoxide is produced upon the charcoal. By the addition of tin, the bead appears of a darker grey, but it is never quite opaque.

_Carbonate of Soda_ dissolves oxide of lead in the flame of oxidation upon platinum wire quite readily to a transparent bead, which becomes yellow when cooling, and is opaque. Upon charcoal in the flame of reduction, it is rapidly reduced to metallic lead, which yields, after a continued blast, a yellow sublimate of oxide upon the charcoal.

(_b._) _Bismuth_ (Bi).--This metal occurs mostly in the metallic state, and less frequently as the sulphide. In the pure metallic state, it is of a reddish-white color and great lustre. It crystallizes in cubes. It is brittle, and may be readily pulverized. It melts at 476°, and is volatilized at a white heat. It is soluble in nitric acid, and forms the nitrate of bismuth.

([alpha].) _Oxide of Bismuth _(Bi^{2}O^{3}).--This oxide is a light yellow powder, fusible at a red heat, insoluble in caustic potash and ammonia. It is the base of the salts of bismuth. Its hydrate is white, and easily soluble in acids. The addition of water causes these solutions to become milky, because they are decomposed into a soluble acidulous and an insoluble basic salt of bismuth.

([beta].) _Peroxide of Bismuth_ (BiO^{2}) is a dark-colored powder, completely soluble in boiling nitric acid, and yielding oxygen; produces, with hydrochloric acid, chlorine gas. It can be heated up to the temperature of 620° without being decomposed; but, exposed to a temperature of 630° it yields oxygen. Mixed with combustible substances, it glows with brightness.

([gamma].) _Bismuthic Acid _(Bi^{2}O^{5}) is a brown powder similar to the peroxide, but is converted by boiling nitric acid into a green, scarcely soluble substance (Bi^{2}O^{3}, Bi^{2}O^{5}). Its hydrate is of a red color.

BLOWPIPE REACTIONS.--Metallic bismuth is converted, when exposed upon platinum wire to the flame of oxidation, into a dark brown oxide, which turns light yellow while cooling. It is slowly volatilized when heated, and a yellow sublimate of oxide is produced upon the charcoal.

Oxide of bismuth melts upon platinum foil in the flame of oxidation very easily into a dark-brown liquid, which changes to a light yellow while cooling. By too strong a heat, it is reduced and penetrates the platinum foil.

Upon charcoal, in the flame of oxidation and of reduction, it is reduced to metallic bismuth, which melts into one or more globules. By a continued blast they are slowly volatilized, and produce a yellow sublimate of oxide upon the charcoal, beyond which a white sublimate of carbonate of bismuth is visible. These sublimates disappear in the flame of reduction, but without communicating any color to it.

_Borax_ dissolves oxide of bismuth upon platinum wire, in the flame of oxidation, easily to a clear yellow bead, which appears colorless after cooling. By the addition of more oxide, the hot bead becomes orange. It turns more yellow while cooling, and when cool is opalescent. Upon charcoal in the flame of reduction, the bead becomes turbid and greyish colored. The oxide is reduced with intumescence to the metallic state, and the bead becomes clear again. The addition of tin promotes the reduction.

_Microcosmic Salt_ dissolves oxide of bismuth upon platinum wire, in the flame of oxidation, to a yellow bead, which becomes colorless after cooling. By the addition of more oxide, the bead is yellowish-brown while hot, and colorless after cooling, but not quite transparent. This bead becomes enamelled when heated by the intermittent flame; also, by the addition of still more of the oxide, after it is cooled.

Upon charcoal, in the flame of reduction, and particularly with the addition of tin, the bead is colorless and transparent while hot, but while cooling becomes of a dark-gray color and opaque.

Oxide of bismuth is reduced, by fusion with carbonate of soda, as well in the oxidating as in the reducing flame, instantly to metallic bismuth.

As the above mentioned higher oxides of bismuth are converted by ignition into oxide of the metal and free oxygen, they have the same behavior before the blowpipe.

As bismuth occurs mostly in the metallic form, it is necessary to know how to distinguish it from metals similar to it. Its brittleness distinguishes it from lead, zinc and tin, as they are readily flattened by a stroke of the hammer, while bismuth is broken to pieces. Bismuth, in this latter respect, might perhaps be mistaken for antimony or tellurium; but, by the following examination, it is easy to separate bismuth from antimony or tellurium.

1. Neither bismuth nor antimony sublimates when heated in a glass tube closed at one end. At a temperature which is about to fuse the glass, tellurium yields a small quantity of a white vapor (some tellurium is oxidized to tellurous acid by the oxygen of the air in the tube). After that, a grey metallic sublimate settles on the sides of the tube.

2. Heated in an open tube, antimony yields a white vapor, which coats the inside of the glass tube, and can be driven by heat from one part of the tube to another without leaving a residue. The metallic globule is covered with a considerable quantity of fused oxide. Tellurium produces, under the same circumstances, an intense vapor, and deposits on the glass a white powder, which melts by heat into globules that run over the glass. The metallic globules are covered by fused, transparent, and nearly colorless oxide, which becomes white while cooling. By a high temperature, and with little access of air, metallic tellurium sublimes with the deposition of a grey powder. Bismuth produces, under similar treatment, scarcely any vapor, unless it is combined with sulphur. The metal is enveloped by fused oxide of a dark yellow color, which appears light yellow after being cooled. It acts upon the glass, and dissolves it.

3. Upon charcoal, exposed to the blowpipe flame, the three metals are volatilized, and yield a sublimate upon the charcoal. That of antimony is white, while those of bismuth and tellurium are dark yellow. By exposing them to the flame of reduction, the sublimate of tellurium disappears and communicates an intense green color to the flame. The antimony incrustation gives a feeble greenish-blue color, while the sublimate of bismuth gives no perceptible color in the light. It is, however, worthy of notice that if the operation takes place in the dark, a very pale blue flame will be seen with the bismuth.

(_c._) _Tin_ (Sn).--This metal does not occur in nature in the metallic state, very seldom in the sulphide, but chiefly in the oxide (tinstone). In the metallic state it is silver-white, possesses a very high lustre, is soft (but harder than lead), ductile, but has not much tenacity, and it is very malleable. The metal when it is cast gives a peculiar creaking noise when twisted or bent, which proceeds from the crystalline structure of the metal. This crystallization is quite clearly manifested by attacking the surface of the metal, or that of tin plate, with acids.

Tin is very slightly tarnished by exposure to the air. It fuses at 442°, and becomes grey, being a mixture of the oxide and the metal. At a high temperature even, tin is but little subject to pass off as vapor. It is soluble in aqua regia, and with the liberation of hydrogen, in hot sulphuric and hydrochloric acids, and in cold dilute nitric acid, without decomposing water, or the production of a gas, while nitrate of tin and nitrate of ammonia are formed. Concentrated nitric acid converts tin into insoluble tin acids.

([alpha].) _Protoxide of Tin_ (SnO) is a dark-grey powder. Its hydrate is white, and is soluble in caustic alkalies. When this solution is heated, anhydrous crystalline black protoxide is separated. The soluble neutral salts of tin-protoxide are decomposed by the addition of water, and converted into acid soluble, and basic insoluble salts.

When protoxide of tin is ignited with free access of air, it takes fire and is converted with considerable intensity into the acids, producing white vapors. This is likewise the case if it is touched by a spark of fire from steel. The hydrate of the protoxide of tin can be ignited by the flame of a candle, and glows like tinder.

([beta].) _Sesquioxide of Tin_ (Sn^{2}O^{3}) is a greyish-brown powder. Its hydrate is white, with a yellow tinge. It is soluble in aqua ammonia and in hydrochloric acid; this solution forms with solution of gold the "purple of Cassius."

([gamma].) _Stannic Acid_ (peroxide, SnO^{2}).--This acid occurs in nature crystallized in quadro-octahedrons, of a brown or an intense black color, and of great hardness (tinstone). Artificially prepared, it is a white or yellowish-white powder. It exists in two distinct or isomeric modifications, one of which is insoluble in acids (natural tin-acid) while the other (tin-acid prepared in the wet way) is soluble in acids. By ignition the soluble acid is converted into the insoluble. Both modifications form hydrates.

_Reactions before the Blowpipe._--Metallic tin melts easily. It is covered in the flame of oxidation into a yellowish-white oxide, which is carried off sometimes by the stream of air which propels the flame. In the reduction flame, and upon charcoal, melting tin retains its metallic lustre, while a thin sublimate is produced upon the charcoal. This sublimate is light-yellow while hot, and gives a strong light in the flame of oxidation, and turns white while cooling. This sublimate is found near to the metal, and cannot be volatilized in the oxidation flame. In the flame of reduction it is reduced to metallic tin. Sometimes this incrustation is so imperceptible that it can scarcely be distinguished from the ashes of the charcoal. If such be the case, moisten it with a solution of cobalt, and expose it to the flame of oxidation, when the sublimate will exhibit, after cooling, a bluish-green color.

Protoxide of tin takes fire in the flame of oxidation, and burns with flame and some white vapor into tin acid, or stannic acid. In a strong and continued reduction flame, it may be reduced to metal, when the same sublimate above mentioned is visible. The sesquioxide of tin behaves as the above.

Stannic acid, heated in the flame of oxidation, does not melt and is not volatilized, but produces a strong light, and appears yellowish while hot, but changing as it cools to a dirty-yellow white color. In a strong and continued flame of reduction, it may be reduced likewise to the metallic state, with the production of the same sublimate as the above.

_Borax_ dissolves tin compounds in the flame of oxidation, and upon platinum wire, very tardily, and in small quantity, to a transparent colorless bead, which remains clear after cooling, and also when heated intermittingly. But if a saturated bead, after being completely cool, is exposed again to the flame of oxidation, at a low red heat, the bead while cooling is opaque, loses its globular form, and exhibits an indistinct crystallization. This is the case too in the flame of reduction, but if the bead is highly saturated, a part of the oxide is reduced.

_Microcosmic Salt_ dissolves the oxides in the flame of reduction very tardily in a small quantity to a transparent colorless bead, which remains clear while cooling. If to this bead sesquioxide of iron is added in proper proportion, the sesquioxide loses its property of coloring the bead, but of course an excess of the iron salt will communicate to the bead its own characteristic color. In the flame of reduction no further alteration is visible.

Tin-oxides combine with carbonate of soda, in the flame of oxidation upon platinum wire, with intumescence to a bulky and confused mass, which is insoluble in more soda. Upon charcoal, in the reduction flame, it is easily reduced to a metallic globule. Certain compounds of tin-oxides, particularly if they contain tantalum, are by fusion with carbonate of soda reduced with difficulty; but by the addition of some borax, the reduction to the metallic state is easily effected.

Tin-oxides exposed to the oxidation flame, then moistened with a solution of cobalt, and exposed again to the flame of oxidation, will exhibit, after having completely cooled, a bluish-green color.

EIGHTH GROUP.--MERCURY, ARSENIC.

These two metals are volatilized at a temperature lower than that of a red heat, and produce, therefore, no reactions with borax and microcosmic salt. Their oxides are easily reduced to the metallic state.

(_a._) _Mercury_ (Hg).--This metal occurs in nature chiefly combined with sulphur as a bisulphide.

It occurs still more rarely in the metallic form, or combined with silver, selenium, or chlorine.

Mercury, in the metallic state, has a strong lustre, and is liquid at ordinary temperatures, whereby it is distinguished from any other metal. It freezes at 40° and boils at 620°, but it evaporates at common temperatures. Pure mercury is unalterable. Upon being exposed to the air, it tarnishes only by admixture with other metals, turns grey on the surface, and loses its lustre. It is soluble in cold nitric acid and in concentrated hot sulphuric acid, but not in hydrochloric acid.

([chi].) _Protoxide of Mercury_ (Hg^{2}O).--It is a black powder, which is decomposed by ignition into metallic mercury and oxygen. By digestion with certain acids, and particularly with caustic alkalies, it is converted into metallic mercury and peroxide. Some neutral salts of the protoxide are only partly soluble in water, as they are converted into basic insoluble and acid soluble salts.

Protoxide of mercury is completely insoluble in hydrochloric acid. Its neutral salts change blue litmus paper to red.

([beta].) _Peroxide of Mercury_ (HgO).--This oxide exists in two allotropic modifications. One is of a brick-red color, and the other is orange. Being exposed to heat, they turn black, but regain their respective colors upon cooling. They are decomposed at a high temperature into metallic mercury and oxygen. They yield with acids their own peculiar salts.

Mercury, in the metallic form, can never be mistaken for any other metal in consequence of its fluid condition at ordinary temperatures.

Exposed to the blowpipe flame, it is instantly volatilized. This is also the case with it when combined with other metals. The oxides of mercury are, in the oxidation and reduction flames, instantly reduced and volatilized. They do not produce any alteration with fluxes, as they are volatilized before the bead melts. Heated with carbonate of soda in a glass tube closed at one end, they are reduced to metallic mercury, which is volatilized, and condenses upon a cool portion of the tube as a grey powder. By cautious knocking against the tube, or by rubbing with a glass rod, this sublimate can be brought together into one globule of metallic mercury. Compounds of mercury can be most completely reduced by a mixture of neutral oxalate of potassa and cyanide of potassium. If the substance under examination contains such a small quantity of mercury that it cannot be distinguished by volatilization, a strip of gold leaf may be attached to an iron wire, and introduced during the experiment in the glass tube. The smallest trace of mercury will whiten the gold leaf in spots.

(_b._) _Arsenic_ (As).--This metal occurs in considerable quantity in nature, chiefly combined with sulphur or metals.

Arsenic, in the metallic state, is of a whitish-grey color, high lustre, and is crystalline, of a foliated structure, and is so brittle that it can be pulverized. It does not melt, but is volatilized at 356°. Its vapor has a strong alliaceous odor. Arsenic sublimes in irregular crystals. By exposure to the air it soon tarnishes, and is coated black. Being mixed with nitrate of potassa and inflamed, it detonates with vehemence. Mixed with carbonate of potassa, it is inflamed by a stroke of the hammer, and detonates violently.

Heated in oxygen gas, it is inflamed, and burns with a pale blue flame to arsenious acid.

([beta].) _Arsenious Acid_ (AsO^{3}).--This acid crystallizes in octahedrons, or, when fused, forms a colorless glass, which finally becomes opaque and enamel-like, or forms a white powder. It sublimes without change or decomposition. When heated for a longer while below the temperature of sublimation, it melts into a transparent, colorless, tough glass. The opaque acid is sparingly soluble in cold water, and still more soluble in hot water. It is converted, by continued boiling, into the transparent acid, which is much more soluble in water. Arsenious acid is easily dissolved by caustic potassa. It is also soluble in hydrochloric acid. This acid occurs associated with antimonious acid, protoxide of tin, protoxide of lead, and oxide of copper. It occurs likewise in very small quantity in ferruginous mineral springs.

([gamma].)_Arsenic Acid_ (AsO^{5}) is a white mass, which readily absorbs moisture and dissolves. It will not volatilize at a low red heat, nor will it decompose. Exposed to a strong heat, it is decomposed, yielding oxygen, and passing into arsenious acid.

_Reactions before the Blowpipe._

Metallic arsenic, heated in a glass tube closed at one end, yields a black sublimate of a metallic lustre, and at the same time gives out the characteristic alliaceous odor. This is the case too with alloys of arsenic, if there is a maximum quantity of arsenic present.

When heated in a glass tube open at both ends, metallic arsenic is oxidized to arsenious acid, which appears as a white crystalline sublimate on the sides of the glass tube. This deposit will occur at some distance from the assay, in consequence of the great volatility of the arsenic. The sublimate can be driven from one place upon the tube to another, by a very low heat. Alloys of arsenic are converted into basic arseniates of metal oxides, while surplus arsenic is converted into arsenious acid, which sublimes on the tube. If too much arsenic is used for this experiment, a dark-brown incrustation will sublime upon the sides of the tube which will give an alliaceous smell. If this sublimate should be deposited near the assay, then it resembles the white sublimate of arsenious acid.

Heated upon charcoal, metallic arsenic is volatilized before it melts, and incrusts the charcoal in the flame of oxidation as a white deposit of arsenious acid. This sublimate appears sometimes of a greyish color, and takes place at some distance from the assay. When heated slightly with the blowpipe flame, this sublimate is instantly driven away, and being heated rapidly in the reduction flame, it disappears with a light blue tinge, while the usual alliaceous or garlic smell may be discerned.

Arsenious acid sublimes in both glass tubes very readily, as a white crystalline sublimate. These crystals appear to be regular octahedrons when observed under the microscope. Upon charcoal it instantly volatilizes, and when heated, the characteristic garlic smell may be observed.

Arsenic acid yields, heated strongly in a glass tube closed at one end, oxygen and arsenious acid, the latter of which sublimes in the cool portions of the tube. Compounds of arsenic produce, in consequence of their volatility, no reactions with fluxes. Being heated upon charcoal with carbonate of soda, they are reduced to metallic arsenic which may be detected by the alliaceous odor peculiar to all the arsenic compounds when volatilized.

NINTH GROUP.--COPPER, SILVER, GOLD.

These metals are not volatile, neither are their oxides. They are reduced to the metallic state, by fusion with carbonate of soda, when they melt to a metallic grain. The oxides of silver and gold are reduced _per se_ to the metallic state by ignition. In the reduction of the oxides of this group, no sublimate is visible upon the charcoal.

(_a._) _Copper_ (Cu).--This metal occurs in the metallic state, also as the protoxide, and as oxides combined with acids in different salts (carbonate of copper as malachite, etc.) The sulphide of copper is the principal ore of copper occurring in nature. In the metallic state, copper is of a red color, has great lustre and tenacity, is ductile and malleable, and crystallizes in octahedrons and cubes. It melts at a bright red heat, is more difficult than silver to fuse, but fuses more readily than gold. It absorbs oxygen while melting. There arises from its surface a fine dust of metallic globules, which are covered with the protoxide. The surface of the metal is likewise covered with the protoxide. Copper exposed to moist air tarnishes, and is converted into hydratic carbonate of copper. When ignited in the open air, it is soon covered with the brownish-red protoxide.

([chi].) _Protoxide of Copper_ (Cu^{2}O).--This oxide occurs in nature, crystallized in octahedrons of a ruby-red color, of a lamellar structure, and transparent. Artificially prepared, it forms a powder of the same color. It is decomposed by dilute acids into salts of peroxide and metal. It is converted by ignition, with free access of air, into peroxide.

([beta].) _Oxide of Copper_ (CuO).--This oxide is a dark-brown or black powder. It is dissolved by acids, with a blue or green-colored solution. It is soluble in aqua ammonia, and the solution is of a dark blue color.

_Reactions before the Blowpipe._--Oxide of copper exposed upon platinum wire to the inmost flame (the blue flame), communicates to the external flame a green color. Heated upon charcoal in the oxidation flame, it melts to a black ball, soon spreads over the charcoal, and is partially reduced.

Exposed to the reduction flame, at a temperature which will not melt copper, it is reduced with a bright metallic lustre, but as soon as the blast ceases, the surface of the metal becomes oxidized, and appears dark brown or black. If the temperature is continued still higher, it melts to a metallic grain.

_Borax_ dissolves the oxide of copper in the flame of oxidation to a clear green-colored bead, even if the quantity of oxide be quite small, but by cooling, the bead becomes blue. In the flame of reduction upon platinum wire, the bead soon becomes colorless, but while cooling presents a red color (protoxide of copper). This bead is opaque, but, if too much of the oxide is added, a part of it is reduced to metal, which is visible by breaking the metallic grain.

Upon charcoal, the oxide is reduced to the metal, and the bead appears colorless after cooling. With the addition of some tin, the bead becomes brownish-red and opaque after cooling.

_Microcosmic Salt_ dissolves oxide of copper in the flame of oxidation to a green bead, not so intensely colored as the borax bead. In the reduction flame the bead, if pretty well saturated, becomes dark-green while hot, and brownish-red when cool, opaque and enamel-like. If the oxide is so little that no reaction is visible, by the addition of some tin, the bead appears colorless while hot, and dark brownish-red and opaque when cold.

_Carbonate of Soda_ dissolves oxide of copper in the oxidation flame upon platinum wire, to a clear, green bead, which loses its color when cooling, and becomes opaque.

Upon charcoal, it is reduced to the metal, the soda is absorbed by the charcoal, and the metallic particles melt with sufficient heat to a grain.

(_b._) _Silver_ (Ag).--This metal occurs in nature in the metallic state, and in combination with other metals, particularly with lead. It also occurs as the sulphide in several mines. It crystallizes in cubes and octahedrons; is of a pure white color, great lustre, is very malleable and ductile, and is softer than copper, but harder than gold. It is not oxidizable, neither at common temperatures nor at those which are considerably higher. It is soluble in dilute nitric acid, and in boiling concentrated sulphuric acid.

([chi].) _Protoxide of Silver_ (Ag^{2}O).--It is a black powder. It is converted by acids and ammonia into oxide and metal.

([beta].) _Oxide of Silver_ (AgO).--It is a greyish-brown or black powder, and is the base of the silver salts. With aqua ammonia, it is converted into the black, fulminating silver.

([gamma].) _Superoxide or Binoxide of Silver_ (AgO^{2}).--This oxide occurs in black needles or octahedral crystals of great metallic lustre. It is dissolved by the oxygen acids with the disengagement of oxygen gas.

_Behavior before the Blowpipe._--When exposed to the flames of oxidation and reduction, the oxides of silver are instantly reduced to the metallic state.

_Borax_ dissolves silver-oxides upon platinum wire in the oxidation flame but partially, while the other portion is reduced, the bead appearing opalescent after cooling, in correspondence to the degree of saturation. The bead becomes grey in the flame of reduction, the reduced silver melting to a grain, and the bead is rendered clear and colorless again.

_Microcosmic Salt_ dissolves oxides of silver in the flame of oxidation upon platinum wire to a transparent yellowish bead, which presents, when much of the oxide is present, an opalescent appearance.

In the flame of reduction, the reaction is analogous to that of borax.

By fusion with carbonate of soda in the oxidation and reduction flames, the silver oxides are instantly reduced to metallic silver, which fuses into one or more grains.

(_c._) _Gold_ (Au).--This metal occurs mostly in the metallic state, but frequently mixed with ores, and with other metals. Gold crystallizes in cubes and octahedrons, is of a beautiful yellow color, great lustre, and is the most malleable and ductile of all the metals. It melts at a higher temperature than copper, gives a green colored light when fused, and contracts greatly when cooling. It does not oxidize at ordinary temperatures, nor when heated much above them. It is soluble in nitro-hydrochloric acid (_aqua regia_).

([chi].) _Protoxide of Gold_ (Au^{2}O).--This oxide is a dark violet colored powder which is converted by a temperature of 540° into metallic gold and oxygen. It is only soluble in aqua regia. Treated with hydrochloric acid, it yields the chloride of gold and the metal. With aqua ammonia, it yields the fulminating gold, which is a blue mass and very explosive.

([chi].) _Peroxide of Gold_ (Au^{2}O^{3}).--This oxide is an olive-green or dark brown powder, containing variable quantities of water. Decomposed at 530°, it yields metallic gold and oxygen.

_Reactions before the Blowpipe._--Oxides of gold are reduced, in both the oxidation and reduction flames, to the metal, which fuses to grains.

_Borax_ does not dissolve it, but it is reduced to the metallic state in this flux in either flame. The reduced metal fuses upon charcoal to a grain.

_Microcosmic Salt_ presents the same reactions as borax.

When fused with soda, upon charcoal, the soda is absorbed, and the gold remains as a metallic grain.

TENTH GROUP.--MOLYBDENUM, OSMIUM.

These metals are not volatile, and are infusible before the blowpipe; but some of their oxides are volatile, and can be reduced to an infusible metallic powder.

(_a._) _Molybdenum_ (Mo) occurs in the metallic state; also combined with sulphur, or as molybdic acid combined with lead. It is a white, brittle metal, and is unaltered by exposure to the air. When heated until it begins to glow, it is converted into a brown oxide. Heated at a continued dull red heat, it turns blue. At a higher temperature, it is oxidized to molybdic acid, when it glimmers and smokes, and is converted into crystallized molybdic acid upon the surface.

([chi].) _Protoxide of Molybdenum_ (MoO).--This oxide is a black powder.

([chi].) _Deutoxide of Molybdenum_ (MoO^{2}).--This oxide is a dark copper-colored crystalline powder.

_Reactions before the Blowpipe._--Metallic molybdenum, its protoxide and binoxide, are converted in the oxidation flame into molybdic acid. This acid fuses in the flame of oxidation to a brown liquid, which spreads, volatilizes, and sublimes upon the charcoal as a yellow powder, which appears crystalline in the vicinity of the assay. This sublimate becomes white after cooling. Beyond this sublimate there is visible a thin and not volatile ore of binoxide, after cooling; this is of a dark copper-red color, and presenting a metallic lustre.

Heated in a glass tube, closed at one end, it melts to a brown mass, vaporizes and sublimates to a white powder upon a cool portion of the tube. Immediately above the assay, yellow crystals are visible; these crystals are colorless after cooling, and the fused mass becomes light yellow-colored and crystalline.

Upon platinum foil, in the flame of oxidation, it melts and vaporizes, and becomes light yellow and crystalline after cooling. In the reduction flame it becomes blue, and brown-colored if the heat is increased.

Upon charcoal, in the reduction flame, it is absorbed by the charcoal; and, with an increase of the temperature, it is reduced to the metal, which remains as a grey powder after washing off the particles of charcoal.

_Borax_ dissolves it, in the oxidation flame, upon platinum wire easily, and in great quantity, to a clear yellow, which becomes colorless while cooling. By the addition of more of the molybdenic acid the bead is dark yellow, or red while hot, and opalescent when cold. In the reduction flame, the color of the bead is changed to brown and transparent. By the addition of more of the acid, it becomes opaque.

_Microcosmic Salt_ dissolves it in the oxidation flame, upon platinum wire, to a clear, yellowish-green bead, which becomes colorless after cooling. In the reduction flame the bead is very dark and opaque, but becomes of a bright green after cooling. This is the case likewise upon charcoal.

_Carbonate of Soda_ dissolves it upon platinum wire in the oxidation flame with intumescence, to a clear bead, which appears milk-white after cooling. Upon charcoal the soda and the molybdic acid are absorbed, the latter is reduced to the metallic state, the metal remaining as a grey powder after washing off the particles of charcoal. When molybdic acid, or any other oxide of this metal, is exposed upon platinum wire, or with platinum tongs, to the point of the blue flame, a yellowish-green color is communicated to the external flame. If also any of the compounds of molybdenum are mixed in the form of a powder with concentrated sulphuric acid and alcohol, and the latter inflamed, the flame of the alcohol appears colored green.

(_c._) _Osmium_ (Os).--This metal occurs associated with platinum. It is of a bluish-grey color, and is very brittle. Ignited in the open air, it is oxidized to volatile osmic acid, which is possessed of a pungent smell, and affects the eyes. It communicates a bright white color to the flame of alcohol. Osmium oxide (OsO^{2}) is converted in the oxidation flame to osmic acid, which is volatilized with a peculiar smell, leaving a sublimate.

In the reduction flame it is reduced to a dark-brown infusible metallic powder. It produces no reactions with fluxes. Carbonate of soda reduces it upon charcoal to an infusible metallic powder, which appears, after washing off the particles of charcoal, of a dark-brown color.

ELEVENTH GROUP.--PLATINUM, PALLADIUM, IRIDIUM, RHODIUM, RUTHENIUM.

These metals are infusible before the blowpipe. They are not volatile, nor are they oxidizable. Their oxides are, in both flames, reduced to a metallic and infusible powder. They give no reactions with fluxes, but are separated in the metallic form. These metals are generally found associated together in the native platinum, also with traces of copper, lead, and iron.

The metal palladium is found native, associated with iridium and platinum. This metal generally occurs in greatest quantity in Brazil.

The metal rhodium is found along with platinum, but in very small quantities.

Iridium occurs in nature associated with osmium, gold, and platinum, in the mines of Russia. Its great hardness has rendered it desirable for the points of gold pens. In South America this metal is found native, associated with platinum and osmium. The latter metal, associated with platinum and iridium, has been found in South America.

As these metals will not oxidize or dissolve, they cannot be separated from each other by the blowpipe with the reagents peculiar to that species of analysis. It is true that colors may be discerned in the beads, but these tints proceed from the presence of small traces of copper, iron, etc.

The ore of osmium and iridium can be decomposed, and the former recognized by its fetid odor. This metal, strongly ignited in a glass tube with nitrate of potash, is converted to the oxide of osmium, which gives an odor not unlike the chloride of sulphur.

As the metals of this group are very rare ones, especially the last four ones, we shall not devote an especial division to each of them. For a more detailed statement of their reactions, the student is referred to the large works upon blowpipe analysis.

CLASS III.

NON-METALLIC SUBSTANCES.

1. _Water_--2. _Nitric Acid_--3. _Carbon_--4. _Phosphorus_ --5. _Sulphur_--6. _Boron_--7. _Silicon_--8. _Chlorine_ --9. _Bromine_--10. _Iodine_--11. _Fluorine_--12. _Cyanogen_ --13. _Selenium_.

(1.) _Water_ (HO).--Pure distilled water is composed of one volume of oxygen, and two volumes of hydrogen gases; or, by weight, of one part of hydrogen to eight parts of oxygen gases. Water is never found pure in nature, but possessing great solvent properties, it always is found with variable proportions of those substances it is most liable to meet with, dissolved in it. Thus it derives various designations depending upon the nature of the substance it may hold in solution, as lime-water, etc.

In taking cognizance of water in relation to blowpipe analysis, we regard it only as existing in minerals. The examination for water is generally performed thus: the substance may be placed in a dry tube, and then submitted to heat over a spirit-lamp. If the water exists in the mineral mechanically it will soon be driven off, but if it exists chemically combined, the heat will fail to drive it off, or if it does, it will only partially effect it. The water will condense upon the cool portions of the tube, where it can be readily discerned. If the water exists chemically combined, a much stronger heat must be applied in order to separate it.

Many substances may be perhaps mistaken for water by the beginner, such as the volatile acids, etc.

(2.) _Nitric Acid_ (NO^{5}).--Nitric acid occurs in nature in potash and soda saltpetre. These salts are generally impure, containing lime, as the sulphate, carbonate and nitrate, and also iron in small quantity. The soda saltpetre generally contains a quantity of the chloride of sodium. The salts containing nitric acid deflagrate when heated on charcoal. Substances containing nitric acid may be heated in a glass tube closed at one end, by which the characteristic red fumes of nitrous acid are eliminated. If the acid be in too minute a quantity to be thus distinguished, a portion of the substance may be intimately mixed with some bisulphate of potash, and treated as above. The sulphuric acid of the bisulphate combines with the base, and liberates the nitric acid, while the tube contains the nitrous acid gas.

The nitrate of potassa, when heated in a glass tube, fuses to a clear glass, but gives off no water. When fused on platinum wire, it communicates to the external flame the characteristic violet color. When fused and ignited on charcoal, its surface becomes frothy, indicating the nitric acid.

(3.) _Carbon_ (C).--Carbon is found in nature in the pure crystallized state as the diamond. It occurs likewise in several allotropic states as graphite, plumbago, charcoal, anthracite, etc. It exists in large quantities combined with oxygen as carbonic acid.

The diamond, although combustible, requires too high a heat for its combustion to enable us to burn it with the blowpipe. When excluded from the air, it may be heated to whiteness without undergoing fusion, but with the free access of air it burns at a temperature of 703° C, and is converted into carbonic acid. If mixed with nitre, the potassa retains the carbonic acid, and the carbon may be thus easily estimated. If a mineral containing carbonic acid is heated, the gas escapes with effervescence, or a strong mineral acid as the hydrochloric will expel the acid with the characteristic effervescence.

(4.) _Phosphorus, Phosphoric Acid _(PO^{6}).--This acid occurs in a variety of minerals, associated with yttria, copper, uranium, iron, lead, manganese, etc. Phosphoric acid may be detected in minerals by pursuing the following process: dip a small piece of the mineral in sulphuric acid, and place it in the platinum tongs: this is heated at the point of the blue flame, when the outer flame will become colored of a greenish-blue hue. This color will not be mistaken for those of boracic acid, copper, or baryta. Some of the phosphoric minerals, when heated in the inner flame, will color the outer flame green.

If alumina be present with the phosphoric acid, the following wet method should be adopted for the detection of the latter: the substance should be powdered in the agate mortar with a mixture of six parts of soda, and one and a half parts of silica. The entire mass should now be placed on charcoal, and melted in the flame of oxidation. The residue should be treated with boiling water, which dissolves the phosphate and the excess of carbonate of soda, while the silicate of alumina, with some of the soda, is left. The clear liquor is now treated with acetic acid, and heated over the spirit-lamp, and a small portion of crystallized nitrate of silver added; a lemon-yellow precipitate of phosphate of silver is quickly developed. Previous to the addition of the nitrate, the liquor should be well heated; otherwise, a white precipitate of dipyrophosphate of silver will be produced.

If the examination be of any of the metallic phosphides, the substances should be powdered in the agate mortar, and fused with nitrate of potassa on the platinum wire; the fused mass should be treated with soda in the same manner as any substance containing phosphoric acid. The metal and the phosphorus are oxidized, while the phosphate of potassa is fused, and the metallic oxide separates.

(5.) _Sulphur_ (S).--Sulphur is found native in crystals It is frequently found associated with lime, iron, silica, carbon, etc., and combined extensively with metals.

The principal acid of sulphur (the sulphuric, SO^{3}) occurs combined with the earths, the alkalies, and the metallic oxides. Native sulphur is recognized, when heated upon charcoal, by its odor (sulphurous acid) and the blue color of its flame. The compounds of sulphur may be detected by several methods. If the substance is heated in a glass tube, closed at one end, the yellow sublimate of sulphur will subside upon the cool portions of the tube; if the substance should also contain arsenic, the sublimate will present itself as a light brown incrustation, consisting of the sulphide of arsenic.

If the assay is heated in the open glass tube, sulphurous acid will thus be generated; but, if the gas is too little to be detected by the smell, a strip of moistened litmus paper will indicate the presence of the acid.

The assay will give off sulphurous fumes if heated in the flame of oxidation.

If the powdered substance is fused with two parts of soda, and one part of borax, upon charcoal, the sulphide of sodium is formed. This salt, if moistened and applied to a polished silver surface, will blacken it. The borax serves no other purpose than to prevent the absorption of the formed sulphide of sodium by the charcoal. As selenium will blacken silver in the manner above indicated, the presence of this substance should be first ascertained, by heating the assay; when, if it be present, the characteristic horse-radish odor will reveal the fact.

Sulphuric acid may be detected by fusing the substance with two parts of soda, and one part of borax, on charcoal, in the flame of reduction; the mass must now be wetted with water, and placed in contact with a surface of bright silver; when, if sulphuric acid be present, the silver will become blackened.

Or the substance may be fused with silicate of soda in the flame of reduction. In this case, the soda combines with a portion of the sulphuric acid, which is then reduced to the sulphide, while the bead becomes of an orange or red color, depending upon the amount of the sulphuric acid present. If the assay should, however, be colored, then the previous treatment should be resorted to.

(6.) _Boron, Boracic Acid_ (BO^{3}).--This acid occurs in nature in several minerals combined with various bases, such as magnesia, lime, soda, alumina, etc. Combined with water, this acid exists in nature as the native boracic acid; this acid gives with test paper prepared from Brazil wood, when moistened with water, a characteristic reaction, for the paper becomes completely bleached. An alcohol solution turns curcuma test paper brown. Heated on charcoal, it fuses to a clear bead; but, if the sulphate of lime be present, the bead becomes opaque upon cooling.

The following reaction is a certain one: the substance is pulverized and mixed with a flux of four and a half parts of bisulphate of potassa, and one part of pulverized fluoride of calcium. The whole is made into a paste with water, and the assay is placed on the platinum wire, and submitted to the point of the blue flame. While the assay is melting, fluoboric gas is disengaged, which tinges the outer flame green. If but a small portion of boracic acid is present, the color will be quite evanescent.

(7.) _Silica, Silicic Acid_ (SiO^{3}).--This acid exists in the greatest plenty, forming no inconsiderable portion of the solid part of this earth. It exists nearly pure in crystallized quartz, chalcedony, cornelian, flint, etc., the coloring ingredients of these minerals being generally iron or manganese.

With _microcosmic salt_, silica forms a bead in the flame of oxidation which, while hot, is clear, while the separated silica floats in it. A platinum wire is generally used for the purpose, the end of it being first dipped in the salt which is fused into a bead, after which the silica must be added, and then the bead submitted to the flame of oxidation.

The silicates dissolve in soda but partially, and then with effervescence. If the oxygen of the acid be twice that of the base, a clear bead will be obtained that will retain its transparency when cold. If the soda be added in small quantity, the bead will then be opaque. In the first instance, a part of the base which separates is re-dissolved, and, therefore, the transparency of the glass; but, if too large a quantity of the soda is added, the separation of the base is sufficient to render the assay infusible.

(8.) _Chlorine_ (Cl).--Chlorine exists in nature always in combination, as the chlorides of sodium, potassium, calcium, ammonium, magnesia, silver, mercury, lead, copper, etc.

The chlorine existing in metallic chlorides may be detected as follows: the wet way may be accomplished in the following manner. If the substance is insoluble, it must be melted with soda to render it soluble; if it be already soluble it must be dissolved in pure water, and nitrate of silver added, when the one ten-thousandth part of chlorine will manifest its presence by imparting a milky hue to the fluid.

By the blowpipe, chlorine may be detected in the following manner: Oxide of copper is dissolved in microcosmic salt on the platinum wire in the flame of oxidation, and a clear bead is obtained. The substance containing the chlorine is now added, and heat is applied. The assay will soon be enveloped by a blue or purplish flame. As none of the acids that occur in the mineral kingdom give this reaction, chlorine cannot be confounded with them, for those which impart a color to the flame, when mixed with a copper salt, will not do so when tested in the microcosmic salt bead as above indicated.

If the assay is soluble in water, the following method may be followed: a small quantity of sulphate of copper or iron is dissolved; a few drops of the solution is placed upon a bright surface of silver, and the metallic chloride added; when, if chlorine is present, the silver is blackened. If the chloride is insoluble in water, it must be rendered soluble by fusion upon a platinum wire with soda, and then treated as above.[2]

[2] Plattner.

(9.) _Bromine_ (Br).--The bromide of magnesium and sodium exists in many salt springs, and it is from these that the bromine of commerce is obtained. The metallic bromides give the same reactions on silver with the microcosmic bead and copper salt as the metallic chlorides. The purplish color which, however, characterizes the chlorides, is more inclined to greenish with the bromides. If the substance be placed in a flask or glass tube, and fused with bisulphate of potassa, over the spirit-lamp, sulphurous gas and bromine will be eliminated. Bromine will be readily detected by its yellow color and its smell. Bromine may be readily detected by passing a current of chlorine through the fluid, after which ether is added and the whole is agitated. The ether rises to the top, carrying with it the bromine in solution; after being withdrawn, this ether is mixed with potassa, by which the bromide and bromate of potassa are formed. The solution is evaporated to dryness, the residue is fused in a platinum vessel, the bromate is decomposed, while the bromide remains; this must be distilled with sulphuric acid and the binoxide of manganese. A red or brown vapor will then appear, indicating the presence of bromine; this vapor will color starch paste--which may be put in the receiver on purpose--of a deep orange color.

If, to a solution containing a bromide, concentrated sulphuric or nitric acid be added, the bromine is liberated and colors the solution yellow or red. The hypochlorites act in the same manner. The bromine salts are coming into use extensively in photography, in consequence of their greater sensitiveness to the action of light than the chlorides alone.

(10.) _Iodine_ (I).--This element occurs in salt-springs, generally combined with sodium; it also exists in rock-salt; it has likewise been found in sea-water, also in a mineral from Mexico, in combination with silver, and in one from Silesia, in combination with zinc. As sea-water contains iodine, we would consequently expect to find it existing in the sea-weeds, and it is generally from the ashes of these that it is obtained in commerce.

When the metallic iodides are fused with the microcosmic salt and copper, as previously indicated, they impart a green color to the flame. This color cannot be mistaken for the color imparted to the flame by copper alone. When the metallic iodides are fused in a glass tube, closed at one end, with the bisulphate of potassa, the vapor of iodine is liberated, and may be recognized by its characteristic color. Those mineral waters containing iodine can be treated the same as for bromine, as previously indicated, while the violet-colored vapor of the iodine can be easily discerned. The nitrate of silver is the best test for iodine, the yellow color of the iodide of silver being not easily mistaken, while its almost insolubility in ammonia will confirm its identity. The chloride of silver, on the contrary, dissolves in ammonia with the greatest facility.

The reactions of iodine are similar to those of bromine with concentrated sulphuric acid and binoxide of manganese, and with nitric acid: The iodine is released and, if the quantity be not too great, colors the liquid brown. If there be a considerable quantity of iodine present, it is precipitated as a dark colored powder. Either of these, when heated, gives out the violet-color of the iodine.

With starch paste free iodine combines, producing a deep blue compound. If, however, the iodine be in very minute quantity, the color, instead of being blue, will be light violet or rose color.

If to a solution of the sulphate of copper, to which a small portion of sulphurous acid has been added, a liquid containing iodine and bromine is poured in, a dirty, white precipitate of the subiodide of copper is produced, and the bromine remains in the solution. The latter may then be tested for the bromine by strong sulphuric acid.

(11.) _Fluorine_ (Fl).--This element exists combined with sodium, calcium, lithium, aluminium, magnesium, yttrium, and cerium. Fluorine also exists in the enamel of the teeth, and in the bones of some animals. This element has a strong affinity for hydrogen, and, therefore, we find it frequently in the form of hydrofluoric acid. Brazil-wood paper is the most delicate test for hydrofluoric acid, which it tinges of a light yellow color. Phosphoric acid likewise colors Brazil paper yellow, but as this acid is not volatile at a heat sufficient to examine hydrofluoric acid, there can be no mistake. If the substance is supposed to contain this acid, it should be placed on a slip of glass, and moistened with hydrochloric acid, when the test paper may be applied, and the characteristic yellow color will indicate the presence of the fluorine.

As hydrofluoric acid acts upon glass, this property may be used for its detection. The substance may be put into a glass tube, and sulphuric acid poured upon it in sufficient quantity to moisten it; a slight heat applied to the tube will develop the acid, which will act upon the glass of the tube. If the acid is retained in the mineral by a feeble affinity, and water be present, a piece of it may be put in the tube and heated, when the acid gas will be eliminated. The test paper will indicate its presence, even before it has time to act upon the glass. If the temperature be too high, fluosilicic acid is generated, and will form a silicious incrustation upon the cool portion of the tube.

If the fluorine is too minute to produce either of the above reactions, then the following process, recommended by Plattner, should be followed: the assay should be mixed with metaphosphate of soda, formed by heating the microcosmic salt to dull redness. The mass must then be placed in an open glass tube, in such a position that there will be an access of hot air from the flame. Thus aqueous hydrofluoric acid is formed, which can be recognized by its smell being more suffocating than chlorine, and also by the etching produced by the condensation of vapor in the tube. Moist Brazil paper, applied to the extremity of the tube, will be instantly colored yellow.

Merlet's method for the detection of this acid is the following:[3] Pulverize the substance for examination, then triturate it to an impalpable powder, and mix it with an equal part of bisulphate of potassa. Heat the mass gradually in a moderately wide test-tube. The judicious application of heat must be strictly observed, for if the operator first heats the part of the tube where the assay rests, the whole may be lost on account of the glass being shattered. The spirit-flame must be first applied to the fore part of the tube, and then made to recede slowly until it fuses the assay. After the mixture has been for some time kept in a molten state, the lamp must be withdrawn, and the part containing the assay severed with a file. The fore part of the tube must then be well washed, and afterwards dried with bibulous paper. Should the fluorine contained in the substance be appreciable, the glass tube, when held up to the light, will be found to have lost its transparency, and to be very rough to the touch.

[3] Quoted by Plattner.

Great care should be observed not to allow this very corrosive acid to come into contact with the skin, as an ulcer will be the consequence that will be extremely difficult to heal.

When hydrofluoric acid comes in contact with any silicious substance, hydrofluosilicic acid gas is always formed.

(12.) _Selenium_ (Se).--This element occurs in combination with lead as the selenide, and with copper as the selenide of copper. It exists also combined with cobalt and lead, as the selenide of these metals; also as the selenide of lead and mercury.

The smallest trace of selenium may be detected by igniting a small piece of charcoal in the flame of oxidation, when the peculiar and unmistakable odor of decayed horse-radish will indicate the presence of that element. An orange vapor is eliminated if the selenium be present in any quantity, while there is an incrustation around the assay of a grey color, with a metallic lustre. This incrustation frequently presents a reddish-violet color at its exterior edges, often running into a deep blue. If a substance containing selenium be placed in a glass tube, closed at one end, and submitted to heat, the selenium is sublimed, with an orange-colored vapor, and with the characteristic odor of that substance. Upon the cool portions of the tube a steel-grey sublimate is deposited, and, beyond that, can be discerned small crystals of selenic acid. If the mineral be the seleniferous lead glance, sulphurous acid gas will be given off, and may be detected by the smell, or by a strip of moistened litmus paper.

If arsenic is present, heating upon charcoal will quickly lead to the determination of the one from the other.

* * * * *

TABULAR STATEMENT OF THE REACTIONS OF MINERALS BEFORE THE BLOWPIPE.

In PART THIRD of this work, commencing at page 109, the student will find a sufficiently explicit description of the blowpipe reactions of those principal substances that would be likely to come beneath his attention. The following tabular statement of those reactions--which we take from Scheerer and Blanford's excellent little work upon the blowpipe--will be of great benefit, as a vehicle for consultation, when the want of time--or during the hurry of an examination--precludes the attentive perusal of the more lengthy descriptions in the text.

In the examination of minerals, before the student avails himself of the aid of the blowpipe, he should not neglect to examine the specimen rigidly in relation to its physical characters, such as its hardness, lustre, color, and peculiar crystallization. It is where the difference of two minerals cannot be distinguished by their physical appearance, that the aid of the blowpipe comes in most significantly as an auxiliary. For instance, the two minerals molybdenite and graphite resemble each other very closely, when examined in regard to their physical appearance, but the blowpipe will quickly discriminate them, for if a small piece of the former mineral be placed in the flame of oxidation, a bright green color will be communicated to the flame beyond it, while in the latter there will be no color. Thus, in a very short time, these two minerals can be distinguished from each other by aid of the blowpipe, while no amount of physical examination could determine that point. The blowpipe is equally an indispensable instrument in the determination of certain minerals which may exist in others as essential or non-essential constituents of them. For instance, should a minute quantity of manganese be present in a mineral, it must be fused with twice its bulk of a mixture of two parts of carbonate of soda, and one part of the nitrate of potassa, in the flame of oxidation upon platinum foil. The manganate of soda thus formed will color the fused mass of a bluish-green tint.

Or a slight quantity of arsenic may be discerned by the following process recommended by Plattner:[4] one grain of the finely pulverized metal is mixed with six grains of citrate of potassa, and slowly heated on the platinum spoon. By this means the metals are oxidized, while the arseniate of potassa is obtained. Then boil the fused mass in a small quantity of water in a porcelain vessel till all tho arseniate is dissolved. The metallic oxides are allowed to subside, and the above solution decanted off into another porcelain vessel. A few drops of sulphuric acid are added, and the solution boiled to expel the nitric acid, after which it is evaporated to dryness. In this operation, the sulphuric acid should be added only in sufficient quantity to drive off the nitric acid, or, at the utmost, to form a bisulphate with the excess of potassa. When dry, the salt thus obtained is pulverized in an agate mortar, and mixed with about three times its volume of oxalate of potassa, and a little charcoal powder. The mixture is introduced into a glass bulb having a narrow neck, and gently warmed over a spirit-lamp in order to drive off the moisture, which must be absorbed by a piece of blotting-paper in the neck of the bulb. After a short time, the temperature is increased to a low red heat, at which the arsenious acid is reduced and the metallic arsenic sublimed, and which re-condenses in the neck of the bulb. If there the arsenic be so small in quantity as to exhibit no metallic lustre, the neck of the bulb may be cut off with a file immediately above the sublimate, and the latter exposed to the flame of the blowpipe, when the arsenic is volatilized, and may be recognized by its garlic odor.

[4] Quoted by Scheerer.

If the presence of cadmium is suspected in zinc-blende, it may be detected by fusing a small piece of the blende upon charcoal in carbonate of soda. The peculiar bright yellow sublimate of the oxide of cadmium, if it be present, will not fail to indicate it. This incrustation can be easily distinguished from that of zinc. Thus, with the three illustrations we have given, the student will readily comprehend the great utility of the blowpipe in the examination of minerals.

Although the following tables were not arranged especially for the last part of this work, still this arrangement is so good that by their consultation the student will readily comprehend at a glance what requires some detail to explain, and we feel no hesitation in saying that, although they are not very copious, they will not fail to impart a vast amount of information, if consulted with any degree of carefulness.

The minerals given are such as are best known to English and American mineralogists under the names specified. For more detailed reactions than could be crowded into a table, the student will have to consult the particular substance as treated in Part Third. If this part is perused carefully previous to consulting the tables, these will be found eminently serviceable as a refresher of the memory, and may thus save much time and trouble.

And, finally, we would certainly recommend the student, after he shall have gone through our little volume (if he is ambitious of making himself a thorough blowpipe analyst), to then take up the larger works of Berzelius and Plattner, for our treatise pretends to nothing more than a humble introduction to these more copious and scientific works.

* * * * *

Mineral. Diamond

Formula. C

Behavior

in glass-bulb. --

on platinum foil. In fine powder is slowly consumed without residue in a strong oxidizing Flame.

* * * * *

Mineral. Graphite

Formula. C with some iron silica, etc.

Behavior

in glass-bulb. Generally gives off water.

on platinum foil. Is slowly consumed leaving more or less ash, principally Fe^{2}O^{3}.

* * * * *

Mineral. Anthracite

Formula. C + x[.H]

Behavior

in glass-bulb. Evolves water.

on platinum foil. Is slowly consumed with the exception of a small quantity of ash.

* * * * *

Mineral. Wallsend-coal

Formula. C, H, O, S and ash.

Behavior

in glass-bulb. Intumesces and gives off water and tarry matters which partly condense in bulb, and leave a porous coke.

on platinum foil. Takes fire under blowpipe flame, and burns with a smoky flame, depositing much soot and leaving a porous cinder which burns slowly and leaves a small ash.

* * * * *

Mineral. Cannel-coal

Formula. C, H, N, O, S and ash.

Behavior

in glass-bulb. As the preceding but gives off more tar.

on platinum foil. Similar to the preceding. If held to the lamp-flame, takes fire and burns for some seconds.

* * * * *

Mineral. Brown-coal

Formula. C, H, N, O, S, and ash.

Behavior

in glass-bulb. Gives off much water and tar, and leaves a porous cinder retaining the form of the original fragment.

on platinum foil. Burns slowly and without flame, leaving some ash.

* * * * *

Mineral. Asphaltum

Formula. C + H + O.

Behavior

in glass-bulb. Fuses with ease affording an empyreumatic oil having an alkaline reaction, and combustible gasses, and leaves a carbonaceous residue, which is entirely consumed under the blowpipe flame, except a little ash.

on platinum foil. Takes fire and burns with a bright flame and a thick smoke.

* * * * *

Mineral. Elaterite

Formula. C + H.

Behavior

in glass-bulb. Fuses and gives off water having an acid reaction, naphtha and a tarry fluid, which chiefly condense in the neck of the bulb, and leave a light, pulverulent carbonaceous residue.

on platinum foil. Fuses, takes fire, and burns with a smoky flame, leaving a carbonaceous residue, which under the blowpipe flame, is quickly consumed, with the exception of the ashes.

* * * * *

Mineral. Hachettine

Formula. C + H.

Behavior

in glass-bulb. Fuses to a clear colorless liquid, which solidifies on cooling and has a tallow-like smell.

on platinum foil. Fuses, takes fire, and burns with a bright flame until entirely consumed.

* * * * *

Mineral. Ozokerite

Formula. C + H.

Behavior

in glass-bulb. Fuses readily to a clear brown oily fluid, which solidifies on cooling.

on platinum foil. As the preceding.

* * * * *

Mineral. Amber

Formula. C + H + O.

Behavior

in glass-bulb. Fuses with difficulty, and affords water, an empyreumatic oil, and succinic acid which condense in the neck of the bulb leaving a shining black residue.

on platinum foil. Takes fire and burns with a yellow flame and a peculiar aromatic odor.

* * * * *

Mineral. Mellite

Formula. [...Al][=M]^{3} + 15[.H]

Behavior

in glass-bulb. Gives off water. If heated to redness, is carbonized, and gives a slight empyreumatic odor.

on platinum foil. On charcoal burns to a white ash, which moistened with nitrate of cobalt and heated shows the alumina reaction.

* * * * *

POTASH.

* * * * *

Mineral. Nitre

Formula. [.K][.....N]

Behavior

(1) in glass-bulb. Fuses readily to a clear liquid and with a strong heat boils with the evolution of oxygen.

(2) in open tube. --

(3) on charcoal. Deflagrates leaving a saline mass, which is absorbed into charcoal and gives a sulphur reaction on silver.

(4) in forceps. On platinum wire fuses and colors the flame violet more or less modified by lime and soda.

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. --

(8) Special reactions. With bisulphate of potassa in the glass-bulb evolves nitrous fumes.

* * * * *

Mineral. Polyhalite

Formula. [.K][...S]+[.Mg][...S]+2[.Ca][...S]+2[.H]

Behavior

(1) in glass-bulb. Gives off water.

(2) in open tube. --

(3) on charcoal. Fuses to a reddish bead, which in the reducing flame solidifies and shrinks to a hollow crust.

(4) in forceps. On platinum wire fuses and colors the flame yellow from a small quantity of soda.

(5) in borax. Dissolves with ebullition to a clear glass, which is slightly colored by iron, and when saturated become opaque on cooling.

(6) in mic. salt. As in borax.

(7) with carb. soda. Fuses. The alkalies are absorbed by the charcoal leaving the lime and magnesia infusible on the surface.

(8) Special reactions. The alkaline mass when laid on silver gives a sulphur reaction.

* * * * *

SODA.

* * * * *

Mineral. Rock-salt

Formula. NaCl.

Behavior

(1) in glass-bulb. Fuses to a clear liquid

(2) in open tube. --

(3) on charcoal. Fuses, is absorbed by the charcoal and partially volatilized incrusting the charcoal around.

(4) in forceps. Fuses with great ease and colors the flame yellow.

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. --

(8) Special reactions. Gives the chlorine reactions.

* * * * *

Mineral. Natron

Formula. [.Na][..C] + 10[.H]

Behavior

(1) in glass-bulb. Fuses, with the evolution of water.

(2) in open tube. --

(3) on charcoal. Fuses, and is absorbed into the pores of the charcoal.

(4) in forceps. Fuses and behaves as the preceding.

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. --

(8) Special reactions. Dissolves in acid with violent effervescence.

* * * * *

Mineral. Soda-nitre

Formula. [.Na][.....N].

Behavior

(1) in glass-bulb. Fuses and if strongly heated evolves nitrous fumes. (2) in open tube. -- (3) on charcoal. Deflagrates and is absorbed into the charcoal.

(4) in forceps. Deflagrates on platinum wire, coloring the flame yellow.

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. --

(8) Special reactions. In a glass-bulb with bisulphate of potassa, gives the NO^{5}-reaction.

* * * * *

Mineral. Glauber-salt

Formula. [.Na][...S] + 10[.H].

Behavior

(1) in glass-bulb. Fuses and gives off water having a neutral reaction.

(2) in open tube. --

(3) on charcoal. Fuses, and is absorbed by the charcoal. The saturated charcoal laid upon silver gives the sulphur reaction

(4) in forceps. Fuses and colors the flame yellow.

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. --

(8) Special reactions. Gives the SO^{3}-reaction.

* * * * *

Mineral. Glauberite

Formula. [.Na][...S] + [.Ca][...S].

Behavior

(1) in glass-bulb. Decrepitates with the evolution of more or less water, and when strongly heated fuses to a clear liquid.

(2) in open tube. --

(3) on charcoal. Fuses to a clear bead, then spreads out; the soda is absorbed and the lime left on the surface. Laid on silver, the fused mass gives a sulphur reaction.

(4) in forceps. Fuses easily to a clear glass, coloring the flame yellow.

(5) in borax. Fuses easily and gives the lime reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. As alone in charcoal.

(8) Special reactions. As in preceding.

* * * * *

Mineral. Borax

Formula. [.Na][...B]^{2}+10[.H].

Behavior

(1) in glass-bulb. Intumesces with the evolution of water, and under a strong heat fuses.

(2) in open tube. --

(3) on charcoal. Intumesces and fuses to a clear bead more or less colored by impurities.

(4) in forceps. As on charcoal.

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. Fuses to a clear bead, which becomes crystalline on cooling.

(8) Special reactions. Gives the boracic-acid-reaction.

* * * * *

Mineral. Cryolite

Formula. 3NaFl+Al^{2}Fl^{3}.

Behavior

(1) in glass-bulb. Decrepitates slightly and gives a trace of water.

(2) in open tube. If heated so that the flame be allowed to play up the tube upon the mineral, flourine is evolved, which corrodes the interior of the tube.

(3) on charcoal. Fuses to a limpid bead, which on cooling becomes a white enamel. If heated for some time, it bubbles, gives off fluorine and becomes infusible.

(4) in forceps. Fuses, coloring the flame yellow.

(5) in borax. Dissolves to a clear bead, which is rendered opaque by a large addition.

(6) in mic. salt. As in borax.

(7) with carb. soda. Fuses to a clear bead, then spreads out on the charcoal, the soda is absorbed, and an infusible mass of alumina remains.

(8) Special reactions. If the alumina residue obtained be moistened with cobalt solution and heated strongly, it assumes a beautiful blue color.

* * * * *

BARYTA AND STRONTIA.

* * * * *

Mineral. Heavy-spar

Formula. [.Ba][...S].

Behavior

(1) in glass-bulb. Sometimes decrepitates and gives off more or less water

(2) in open tube. --

(3) on charcoal. Fuses in the reducing flame.

(4) in forceps. Fuses with difficulty on edges. Colors the outer flame green. In reducing flame forms BaS, which fuses readily.

(5) in borax. Gives the baryta-reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Fuses to a clear bead; then spreads out and is absorbed into the charcoal. The fused mass laid on silver gives the S-reaction.

(8) Special reactions. If fused with potassa on platinum, gives the SO^{3}-reaction.

* * * * *

Mineral. Celestine

Formula. [.Sr][...S].

Behavior

(1) in glass-bulb. --

(2) in open tube. --

(3) on charcoal. Fuses to a milk-white bead.

(4) in forceps. Colors the flame crimson.

(5) in borax. Gives the strontia-reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Similar to the preceding.

(8) Special reactions. Similar to the preceding.

* * * * *

Mineral. Witherite

Formula. [.Ba][..C].

Behavior

(1) in glass-bulb. Decrepitates more or less and evolves Water.

(2) in open tube. --

(3) on charcoal. Fuses, effervesces, and is partially absorbed by the charcoal.

(4) in forceps. Colors the outer flame intensely green.

(5) in borax. Dissolves with effervescence and gives the baryta-reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Fuses to a clear bead; then spreads out and passes into the charcoal.

(8) Special reactions. In dilute HCl dissolves with much effervescence.

* * * * *

Mineral. Strontianite

Formula. [.Sr][..C].

Behavior

(1) in glass-bulb. Becomes opaque.

(2) in open tube. --

(3) on charcoal. As in the forceps.

(4) in forceps. Exfoliates and becomes arborescent. The filaments glow brilliantly and fuse on the point. Colors the flame brilliantly crimson.

(5) in borax. Resembles the preceding.

(6) in mic. salt. As in borax.

(7) with carb. soda. As the preceding.

(8) Special reactions. As the preceding.

* * * * *

Mineral. Barytocalcite.

Formula. [.Ba][..C] + [.Ca][..C].

Behavior

(1) in glass-bulb. As in the preceding.

(2) in open tube. --

(3) on charcoal. In powder frits together, but does not fuse.

(4) in forceps. Colors the flame green in the centre and red towards the point.

(5) in borax. Dissolves with effervescence. In large quantities gives a semi-crystalline bead.

(6) in mic. salt. As in borax, but the saturated bead is milk-white.

(7) with carb. soda. Fuses, and is partially absorbed leaving the lime on the surface.

(8) Special reactions. As witherite.

* * * * *

LIME.

* * * * *

Mineral. Gypsum

Formula. [.Ca][...S] + 2[.H].

Behavior

(1) in glass-bulb. Turns white, giving off water and being converted into plaster of Paris.

(2) in open tube. --

(3) on charcoal. In the reducing flame forms CaS, which has an alkaline reaction on test paper, and gives a sulphur-reaction when laid on silver and moistened.

(4) in forceps. Fuses with difficulty to a bead, coloring the flame red.

(5) in borax. Dissolves to a clear bead, which gives the lime- reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Behaves as lime. The alkaline mass laid on silver and moistened gives the sulphur-reaction.

(8) Special reactions. Gives the sulphuric-acid reaction.

* * * * *

Mineral. Apatite { Cl Formula. [.Ca]{ -- +3[.Ca]^{3}[.....P] { Fl Behavior

(1) in glass-bulb. Occasionally decrepitates and gives off some water.

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. IV. Previously dipped in SO^{3} colors the flame green, afterwards red.

(5) in borax. Dissolves easily and when in some quantity gives an opaline bead.

(6) in mic. salt. Gives the lime-reaction.

(7) with carb. soda. Is infusible. The alkali is absorbed, leaving the lime on the on the surface of the charcoal.

(8) Special reactions. With microcosmic salt and oxide of copper, gives the chlorine-reaction. With microcosmic salt in the open tube evolves fluorine.

* * * * *

Mineral. Pharmacolite

Formula. [.Ca]^{2}[.....As] + 6[.H].

Behavior

(1) in glass-bulb. Gives off water, and emits an arsenical odor.

(2) in open tube. --

(3) on charcoal. Fuses to an opaque bead and emits a strong smell of arsenic.

(4) in forceps. Fuses to a translucent violet colored bead, the color being due to cobalt. Colors the flame blue at first, then faintly red.

(5) in borax. Dissolves readily to a bead strongly colored by cobalt, which obscures the lime-reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Fuses, and emits As. The alkali is then absorbed by the charcoal, as in the preceding.

(8) Special reactions. --

* * * * *

Mineral. Calespar

Formula. [.Ca][..C].

Behavior

(1) in glass-bulb. Turns white and sometimes decrepitates. Strongly heated loses CO^{2} and becomes caustic.

(2) in open tube. --

(3) on charcoal. Turns white, or brown if containing much iron or manganese and glows brilliantly.

(4) in forceps. Glows brilliantly, coloring the flame red. Becomes caustic and shows a strong alkaline reaction.

(5) in borax. Dissolves with evolution of CO^{2} and when pure gives the lime-reaction. The bead is generally more or less colored by iron and manganese.

(6) in mic. salt. As in borax.

(7) with carb. soda. Fuses, and behaves as other lime-salts.

(8) Special reactions. Dissolves with effervescence in cold HCl.

* * * * *

Mineral. Fluorspar

Formula. CaFl

Behavior

(1) in glass-bulb. Phosphoresces with various colors, when heated in the dark.

(2) in open tube. --

(3) on charcoal. Fuses easily to a clear bead, which becomes opaque on cooling, then loses fluorine, glows brilliantly and becomes infusible.

(4) in forceps. As on charcoal. Colors the flame red.

(5) in borax. Gives the lime-reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Fuses to a clear bead, opaque on cooling. With an addition of the alkali behaves as lime.

(8) Special reactions. With microcosmic salt in open tube gives the fluorine-reaction.

* * * * *

MAGNESIA.

* * * * *

Mineral. Brucite

Formula. [.Mg][.H].

Behavior

(1) in glass-bulb. Evolves water.

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. V.

(5) in borax. Behaves as magnesia. Sometimes gives a faint iron-reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Behaves as magnesia.

(8) Special reactions. With nitrate of cobalt, gives the magnesia reaction

* * * * *

Mineral. Epsomite

Formula. [.Mg][...S] + 7[.H].

Behavior

(1) in glass-bulb. Evolves water having an acid reaction on test paper.

(2) in open tube. --

(3) on charcoal. Gives of HO and SO^{3}, shines brilliantly, and becomes alkaline and caustic.

(4) in forceps. V. As on charcoal.

(5) in borax. Behaves as magnesia.

(6) in mic. salt. As in borax.

(7) with carb. soda. The alkali is absorbed leaving the magnesia on surface of the charcoal. Gives the sulphur-reaction on silver.

(8) Special reactions. The magnesian residue obtained on treating with carbonate of soda (7), assumes a flesh-tint, when treated with cobalt.

* * * * *

Mineral. Boracite

Formula. [.Mg][...B]^{2} + 2[.Mg][...B].

Behavior

(1) in glass-bulb. Occasionally gives off a trace of water.

(2) in open tube. --

(3) on charcoal. Fuses with intumescence to a white crystalline bead.

(4) in forceps. I. As on charcoal. Colors the flame green.

(5) in borax. Fuses easily to a clear bead, which is crystalline, when containing much of the mineral, and is usually slightly tinted by iron.

(6) in mic. salt. As in borax.

(7) with carb. soda. With a small quantity of alkali fuses to a clear bead on cooling. With a larger quantity gives a clear, uncrystallizable bead.

(8) Special reactions. --

* * * * *

Mineral. Magnesite

Formula. [.Mg][..C].

Behavior

(1) in glass-bulb. Sometimes gives off a small quantity of water.

(2) in open tube. --

(3) on charcoal. Is infusible. With cobalt-solution, assumes a dusky flesh tint.

(4) in forceps. --

(5) in borax. Behaves as magnesia. Sometimes a slight iron-reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Fuses to a bead, the soda is then absorbed, leaving an infusable mass of magnesia.

(8) Special reactions. The magnesian residue obtained by fusing with carbonate of soda gives the magnesian-reaction with nitrate of cobalt. Dissolves with effervescence in warm HCl.

* * * * *

Mineral. Mesitine spar

Formula. ([.Mg][.Fe][.Mn])[..C].

Behavior

(1) in glass-bulb. As magnesite.

(2) in open tube. --

(3) on charcoal. Is infusible. Assumes a deep brown color.

(4) in forceps. V.

(5) in borax. Gives the iron and manganese-reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. As magnesite, but the residual mass has a dark color from iron and manganese.

(8) Special reactions. Dissolves with effervescense in warm HCl. With carbonate of soda and nitre gives a manganese-reaction.

* * * * *

ALUMINA.

* * * * *

Mineral. Sapphire Corundum Emery

Formula. [...Al=].

Behavior

(1) in glass-bulb. --

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. V.

(5) in borax. In fine powder dissolves slowly to a colorless glass.

(6) in mic. salt. As in borax.

(7) with carb. soda. --

(8) Special reactions. In fine powder moistened with cobalt-solution and heated yields a blue color.

* * * * *

Mineral. Websterite

Formula. [...Al][...S] + 9[.H].

Behavior

(1) in glass-bulb. Gives off water, and, when heated to incipient redness, sulphurous acid.

(2) in open tube. --

(3) on charcoal. Gives off water and SO^{3}, leaving an infusible mass.

(4) in forceps. V.

(5) in borax. Behaves as alumina.

(6) in mic. salt. As in borax.

(7) with carb. soda. Yields an infusible mass, which laid on silver and moistened, produces a black stain.

(8) Special reactions. Fused with potassa in platinum has no action on silver. Cobalt-solution produces the alumina reaction.

* * * * *

Mineral. Native Alum

Formula. [.R][...S] + [...Al][...S]^{3} + 24[.H].

Behavior

(1) in glass-bulb. Intumesces greatly and gives off much water. Strongly heated, evolves SO^{3}, which reddens litmus.

(2) in open tube. --

(3) on charcoal. Intumesces and become infusible.

(4) in forceps. V. Colors the flame violet if a potassa alum--yellow if soda--be present.

(5) in borax. Dissolves and gives the iron and manganese reaction, if these oxides be present. Otherwise the bead is colorless.

(6) in mic. salt. As in borax.

(7) with carb. soda. The alkali is absorbed into the charcoal, leaving an infusable mass which gives the sulfur reaction on silver.

(8) Special reactions. If not containing too much iron or manganese gives an alumina reaction with nitrate of of cobalt. In other respects as the preceding.

* * * * *

Mineral. Turquoise

Formula. [...Al=]^{2}[.....P] + 5[.H].

Behavior

(1) in glass-bulb. Evolves water, occasionally decrepitates and turns black.

(2) in open tube. --

(3) on charcoal. Turns brown, but remains infusible.

(4) in forceps. V. As on charcoal. Colors the outer flame green.

(5) in borax. In the oxidizing flame, gives a green bead, due to copper and iron. In reducing flame, opaque red.

(6) in mic. salt. As in borax.

(7) with carb. soda. Intumesces, then fuses to a semi-clear glass colored by iron. With more alkali yields an infusible mass.

(8) Special reactions. Gives the phosphoric-acid reaction.

* * * * *

Mineral. Wavellite

Formula. [Al=]F^{3} + 3([...Al=]^{4}[.....P]^{3} + 18[.H].)

Behavior

(1) in glass-bulb. Evolves water and some fluorine, which attacks the glass.

(2) in open tube. --

(3) on charcoal. Exfoliates and turns white.

(4) in forceps. V. As on charcoal. Colors the outer flame green, especially if moistened with SO^{3}.

(5) in borax. As alumina. Generally gives also a slight iron reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Forms an infusible white mass.

(8) Special reactions. With cobalt-solution on charcoal gives the alumina reaction.

* * * * *

Mineral. Spinel

Formula. [.R][...Al=].

Behavior

(1) in glass-bulb. --

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. V.

(5) in borax. Gives a slight iron reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Fuses partially and forms a porous mass.

(8) Special reactions. With nitrate of cobalt gives the alumina reaction. With nitre and carbonate of soda a slight manganese reaction.

* * * * *

SILICATES.

The presence of silica in a mineral can easily be ascertained by treating a small fragment in a bead of microcosmic salt. The bases will dissolve out with more or less difficulty in the salt, and the silica being insoluble will remain suspended in the bead, retaining the original form of the fragment. In borax, the silicates of lime and magnesia generally dissolve with considerable ease, but those of alumina slowly and with difficulty. The silicates of lime are moreover frequently characterized by intumescence or ebullition, when heated in the forceps in the blowpipe flame. The minerals presenting this character are marked in the table. As the most convenient mode of classifying the silicates for blowpipe examination, the following arrangement will be adopted:

TABLE I.--ANHYDROUS SILICATES.

TABLE II.--HYDROUS SILICATES.

FUSIBILITY.

I. Readily fusible to a bead. II. With difficulty fusible to a bead. III. Readily fusible on the edges. IV. With difficulty fusible on the edges. V. Infusible.

a. Afford a fluid bead with carbonate of soda. b. Afford a fluid bead with but little of that salt, but with a larger quantity a slaggy mass. c. Afford a slaggy mass only.

This classification of minerals, according to their fusibility and their behavior with carbonate of soda, was originally proposed by _Berzelius_, and a table of the principal oxidized minerals arranged according to these characters is given in his handbook of the blowpipe, and thence adopted, with some alterations by _Plattner_, in the very excellent and detailed work already many times cited. In the following general table I., the more important silicates only are included, and in table II. are enumerated in alphabetical order those which afford characteristic reactions.

TABLE I.

Anhydrous Silicates. ________________________________________________________________________ Fus. alone and with NaC.

Mineral. Formula. ________________________________________________________________________ I. a. Axinite ([.Ca][.Mg])^{3}([...B][...Si])^{3} + ([...Al=][...Fe=][...Mn=])^{2}([...Si][...B]) Int. Elaolite ([.K][.Na])^{3}[...Si] + 3[...Al=][...Si] Int. Garnet [.R]^{3}[...Si] + [.R=][...Si] Oligoclase [.Na][...Si] + [...Al=][...Si]^{2} Scapolite ([.Ca][.Na])^{3}[...Si]^{2} + 2[...Al=][...Si] Int. Spodumene ([.Li][.Na])^{3}[...Si]^{2} + 4[...Al=][...Si]^{2}Int. b. Asbestos As Hornblende to II. Augite ([.Ca][.Mg][.Fe][.Mn])^{3}[...Si]^{2} Int. some var. Epidote ([.Ca]Fe)^{3}[...Si] + Int. to III. 2([...Al][...Fe][...Mn])[...Si] Hornblende ([.Ca][.Mg][.Fe])^{4} + ([...Si][...Al=])^{3} Int. some var. Sodalite [.Na]^{3}[...Si] + 3[...Al=][...Si] + NaCl Int. to III. Vesuvian 3([.Ca][.Mg])^{3}[...Si] + 2([...Al=][...Fe=])[...Si] Int. c. Biaxial Mica [.K][...Si] + 4([...Al=][...Fe=])[...Si] to III. Hauyne ([.K][.Na])^{3}[...Si] + 3[...Al=][...Si] + [.Na][...Si] Tourmaline ([.R][...R=][...B])^{4}[...Si]^{3} Int. to V.

II. a. Labradorite ([.Ca][.Na][.K])[...Si] + ([...Al=][...Fe=])[...Si] Lepidolite (KNaL)F + ([...Al=][...Fe=])[...Si]^{2}? Ryacolite [.K][...Si] + [...Al=][...Si]^{2} Albite [.Na][...Si] + [...Al=][...Si]^{3} b. Augite [.R]^{3}[...Si]^{2} some var. Actinolite ([.Ca][.Mg][.Fe])^{4}[...Si]^{3} Int. Diopside ([.Ca][.Mg])^{3}[...Si]^{2} | Humboltilite 2([.Ca][.Mg][.Na][.K])[...Si] + ([...Al=][...Fe=])[...Si] Sahlite As Augite Tremolite ([.Ca][.Mg])^{4}[...Si]^{3} c. Pyrope ([.Ca][.Mg][.Fe])^{3}[...Si] + Al[...Si] + m[...Cr]?

III. a. Anorthite ([.Ca][.Mg][.Na][.K])^{3}[...Si] + 3([...Al=][...Fe=])[...Si] Nepheline ([.Na][.K][.Ca])^{2}[...Si] + 2[...Al=][...Si] Obsidian [...Si],[...Al=],[...Fe=],[.Fe],[.Ca][.Na][.K] Int. Orthoclase ([.K][.Na])[...Si] + [...Al=][...Si]^{3} Petalite ([.Li][.Na])^{3}[...Si]^{4} + 4[...Al=][...Si]^{4} Pumice [...Si],[...Al=],[.Ca],[.K],[.Na],[.H] Int. b. Gadolinite ([.Y][.Ce][.La][.Fe][.Ca])^{3}[...Si] to V. Nephrite ([.Ca][.Mg][.Fe])^{4}[...Si]^{3}? Int. Wollastonite [.Ca]^{3}[...Si]^{2} | c. Iolite ([.Mg][.Fe])^{3}[...Si]^{2} + 3[...Al=][...Si]

IV. a. Beryl [...Be][...Si]^{2} + [...Al=][...Si]^{2} b. Diallage ([.Ca][.Mg][.Fe])^{3}([...Si][...Al=])^{2} Hypersthene ([.Mg][.Fe])^{3}[...Si]^{2} | c. Fuchsite ([.K]^{5}[...Si])^{2} + 9([...Al=][...Cr=])^{6}[...Si]^{6} V. a. Leucite [.K]^{3}[...Si]^{2} + [...Al=][...Si]^{2} b. Chondrodite ([.Mg],[.Mg]F)^{4}([...Si]SiF^{3}) Olivine ([.Mg][.Fe][.Ca])^{2}[...Si] c. Andalusite ([...Al=]Fe)^{3}[...Si]^{2} Chrysoberyl [...Be] + [...Al=] Kaynite [...Al=]^{3}[...Si]^{2} Pycnite 6[...Al=]^{3}[...Si]^{2} + (3[...Al=]F^{3} + 2[...Si]F^{3}) Topaz 6[...Al=]^{3}[...Si]^{2} + (3[...Al=]F^{3} + 2[...Si]F^{3}) Zircon [...Zr=][...Si] Staurolite ([...Al=]Fe)^{2}[...Si] ________________________________________________________________________

Hydrous Silicates. ________________________________________________________________________ Fus. alone and with NaC.

Mineral. Formula. ________________________________________________________________________ I. a. Analcime [.Na]^{3}[...Si]^{2} + 3[...Al=][...Si]^{2} + 6[.H] Int. Apophyllite ([.K], KF)([...Si], SiF^{3}) + 6[.Ca][...Si] + 15[.H] Int. Brewsterite ([.Sr][.Ba])[...Si] + [...Al=][...Si]^{3} + 5[.H] Int. Chabasite ([.Ca],[.Na],[.K])^{3}[...Si] + 3[...Al=][...Si]^{2} + 18[.H] Int. Lapis Lazuli [...Si],[...S],[...Al=], Fe, [.Ca], [.Na], [.H] Laumonite [.Ca]^{3}[...Si]^{2} + 3[...Al=][...Si]^{2} + 12[.H] Int. Mesotype ([.Na][.Ca])[...Si] + [...Al=][...Si] + 3[.H] Int. Natrolite [.Na][...Si] + [...Al=][...Si] + 2[.H] Int. Prehnite [.Ca]^{2}[...Si] + [...Al=][...Si] + [.H] Int. Scolezite [.Ca][...Si] + [...Al=][...Si] + 3[.H] Int. Thomsonite ([.Ca][.Na])^{3}[...Si] + 3[...Al=][...Si] + 7[.H] Int. Datholite 2[.Ca]^{3}[...Si] + [...B]^{3}[...Si]^{2} + 3[.H] Int. Heulandite [.Ca][...Si] + [...Al=][...Si]^{3} + 5[.H] Int. Stilbite [.Ca][...Si] + [...Al=][...Si]^{3} + 6[.H] Int. b. Okenite [.Ca]^{3}[...Si]^{4} + 6[.H] Int. Pectolite ([.Ca][.Na])^{4}[...Si]^{3} + [.H] Int. c. Saponite 2[.Mg]^{3}[...Si]^{2} + [...Al=][...Si] + 10 or 6[.H] II. a. Antrimolite 3([.Ca][.K])[...Si] + 5[...Al=][...Si] + 15[.H] Harmatome [...Ba][...Si] + [...Al=]S^{2} + 5[.H] b. Brevicite [.Na][...Si] + [...Al=][...Si] + 2[.H] Orthite [.R]^{3}[...Si] + [...R=][...Si] + ([.H]?) Int.

III. c. Pitchstone [...Si],[...Al=], Fe, [.Mg][.Na], [.K][.H] Talc to V. [.Mg]^{6}[...Si]^{5} + 2[.H] Chlorite 3([.Mg]Fe)^{3}[...Si] + ([...Al=]Fe)^{2}[...Si] + 9[.H] Pinite [...Si],[...Al=],[.Fe],[.K],[.Mg],[.H]

IV. a. Steatite [.Mg]^{6}[...Si]^{5} + 4[.H] c. Gilbertite [...Si],[...Al=],[.Fe],[.Mg],[.H] Int. Meerschaum [.Mg][...Si] + [.H] | Serpentine [.Mg]^{9}[...Si]^{4} + 6[.H] | V. a. Gismondine ([.Ca][.K])^{2}[...Si] + 2[...Al=][...Si] + 9[.H] ________________________________________________________________________

TABLE II.

_______________________________________________________________________ | Analcime | If transparent becomes white and opaque when heated, | but on incipient fusion resumes its transparency and | then fuses to a clear glass. | Andalusite | When powdered and treated with cobalt solution on | charcoal, assumes a blue color. | Apophyllite | Fuses to a frothy white glass. | Axinite | Imparts a green color to the blowpipe flame, owing to | the presence of boracic acid. This reaction is | especially distinct, if the mineral be previously mixed | with fluorspar and bisulphate of potassa. | Beryl | Sometimes gives a chromium reaction in borax and | microcosmic salt. | Chabasite | Fuses to a white enamel. | Chondrodite | Evolves fluorine in the glass tube, both when heated | alone and with microcosmic salt. It sometimes also | gives off a trace of water. | Chrysoberyl | Is unattacked by carbonate of soda. With nitrate of | cobalt on charcoal the finely powdered mineral | assumes a blue color. | Datholite | Fuses to a clear glass and colors the flame green. | Diallage | Frequently gives off water in small quantity. | Fuchsite | Gives the chromium reaction with borax and microcosmic | salt. | Gadolinite | That from Hitteroe, if heated in a partially covered | platinum spoon to low redness, glows suddenly and | brilliantly. | Hauyne | Affords the sulphur reaction both on charcoal and when | fused with potassa. It contains both sulphur and | sulphuric acid. | Hypersthene | As Diallage. | Kyanite | As Andalusite. | Lapis Lazuli | Fuses to a white glass, and when treated with carbonate | of soda on charcoal, gives the sulphur reaction on | silver. | Laumonite | When strongly heated, exfoliates and curls up. | Lepidolite | Colors the blowpipe flame crimson, from lithia; also | gives the fluorine reaction with microcosmic salt. | Leucite | Some varieties, when treated with cobalt solution, | assume a blue color. | Meerschaum | In the glass bulb frequently blackens and evolves an | empyreumatic odor due to organic matter. When this is | burnt off, it again becomes white, and if moistened | with nitrate of cobalt solution and heated, assumes | a pink color. | Okenite | Behaves as Apophyllite. | Olivine | Some varieties give off fluorine, when fused with | microcosmic salt. | Pectolite | Similar to Apophyllite. | Petalite | Imparts a slight crimson color to the flame, like | Lepidolite. | Prehnite | As Chabasite. | Pycnite | Assumes a blue color, when treated with nitrate of | cobalt. Gives the fluorine reaction with microcosmic | salt. | Pyrope | Gives the chromium reaction with borax and microcosmic | salt. | Scolecite | Similar to Laumonite, but more marked. | Scapolite | Occasionally contains a small quantity of lithia, and | colors the flame red when fused with fluorspar and | bisulphate of potassa. | Sodalite | If mixed with one-fifth its volume of oxide of copper, | moistened to make the mixture cohere, and a small | portion placed upon charcoal and heated with the blue | oxidizing flame, the outer flame will be colored | intensely blue from chloride of copper. | | Spodumene | When not too strongly heated, colors the blowpipe | flame red, when more strongly, yellow. | Stilbite | As Chabasite. | Topaz | When heated, remains clear. Otherwise as Pycnite. | Tourmaline | Gives the boracic acid reaction with flourspar and | bisulphate of potassa. | Wollastonite | Colors the blowpipe flame faintly red from lime. | Zircon | The colored varieties become white or colorless and | transparent, when heated. Is only slightly attacked | by carbonate of soda. ______________|________________________________________________________

* * * * *

URANIUM.

* * * * *

Mineral. Pitchblende

Formula. [.U][...U=] essentially.

Behavior

(1) in glass-bulb. Evolves some water and a small quantity of sulphur, sulphide of arsenic and metallic arsenic.

(2) in open tube. Evolves SO^{2} and a white sublimate of arsenious acid.

(3) on charcoal. Gives off arsenical fumes.

(4) in forceps. III. Colors the flame blue beyond the assay, owing to the presence of Pb. Sometimes also green towards the point, due to Cu.

(5) in borax. The roasted mineral affords the uranium reaction.

(6) in mic. salt. As borax. Also a small residue of silica.

(7) with carb. soda. Infusible. Affords the characteristic Pb incrustation, and sometimes yields minute particles of Cu.

(8) Special reactions. --

* * * * *

Mineral. Uranium ochre

Formula. [...U=][.H]^{2}. Behavior

(1) in glass-bulb. Evolves water and assumes a red color.

(2) in open tube. --

(3) on charcoal. V. In reducing flame assumes a green color.

(4) in forceps. --

(5) in borax. Gives the uranium reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. --

(8) Special reactions. --

* * * * *

Mineral. Uranite

Formula. ([.Ca] +[...U=]^{2})[.....]P + 8[.H].

Behavior

(1) in glass-bulb. Evolves water and becomes yellow and opaque.

(2) in open tube. --

(3) on charcoal. Fuses with intumescence to a black bead having a semi-crystalline surface.

(4) in forceps. --

(5) in borax. Gives the uranium reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Forms an infusible yellow slag.

(8) Special reactions. Gives the PO^{5} reaction.

* * * * *

Mineral. Chalcolite

Formula. ([.Cu]+[...U=]^{2})[.....P] + 8[.H].

Behavior

(1) in glass-bulb. As uranite.

(2) in open tube. --

(3) on charcoal. As uranite.

(4) in forceps. As uranite.

(5) in borax. In the oxidizing flame gives a green bead, which in the reducing flame becomes of an opaque red, from Cu.

(6) in mic. salt. As in borax.

(7) with carb. soda. In reducing flame yields a metallic bead of Cu.

(8) Special reactions. As uranite.

* * * * *

IRON.

* * * * *

Mineral. Iron pyrites

Formula. FeS^{2}.

Behavior

(1) in glass-bulb. Gives a considerable yellow sublimate of sulphur, and sometimes sulphide of arsenic. Also HS.

(2) in open tube. Sulphurous acid and sometimes arsenious acid are evolved.

(3) on charcoal. Gives off some sulphur, which burns with a blue flame. Residue fuses to a magnetic bead.

(4) in forceps. --

(5) in borax. The roasted mineral gives a strong iron reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Fuses to a black mass, which spreads out on charcoal and gives the sulphur reaction on silver.

(8) Special reactions. --

* * * * *

Mineral. Magnetic pyrites

Formula. [,Fe]^{5}[,,,Fe=]. Behavior

(1) in glass-bulb. --

(2) in open tube. Evolves sulphurous acid.

(3) on charcoal. Fuses to a magnetic bead black on the surface, and with a yellow shining fracture.

(4) in forceps. --

(5) in borax. As iron pyrites.

(6) in mic. salt. As in borax.

(7) with carb. soda. As iron pyrites.

(8) Special reactions. --

* * * * *

Mineral. Mispickel

Formula. FeAs + FeS^{2}.

Behavior

(1) in glass-bulb. A red sublimate of AsS^{2} is first formed and then a black sublimate of metallic arsenic.

(2) in open tube. Sulphurous and arsenious acids are evolved, the latter forming a white sublimate.

(3) on charcoal. Gives off much arsenic forming a white incrustation and fuses to a magnetic globule.

(4) in forceps. --

(5) in borax. As iron pyrites.

(6) in mic. salt. As in borax.

(7) with carb. soda. As iron pyrites.

(8) Special reactions. --

* * * * *

Mineral. Magnetic iron ore

Formula. Fe^{3}O^{4}

Behavior

(1) in glass-bulb. --

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. In the blue flame, fuses on edges and remains magnetic.

(5) in borax. Gives the iron reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. --

(8) Special reactions. --

* * * * *

Mineral. Specular iron Red haematite

Formula. Fe^{2}O^{3}

Behavior

(1) in glass-bulb. --

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. V. In the blue flame is converted into Fe^{2}O^{4}, and then behaves as the preceding.

(5) in borax. As magnetic iron ore.

(6) in mic. salt. As in borax.

(7) with carb. soda. --

(8) Special reactions. --

* * * * *

Mineral. Göthite

Formula. [...Fe][.H].

Behavior

(1) in glass-bulb. Evolves water.

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. As specular iron.

(5) in borax. As specular iron.

(6) in mic. salt. As in borax.

(7) with carb. soda. --

(8) Special reactions. --

* * * * *

Mineral. Franklinite

Formula. ([.Fe][.Zn][.Mn]) ([...Fe=][...Mn=]).

Behavior

(1) in glass-bulb. --

(2) in open tube. --

(3) on charcoal. Forms a white incrustation on the charcoal, which moistened with cobalt solution assumes a green color.

(4) in forceps. V. In the blue flame fuses on edges and and becomes magnetic.

(5) in borax. Gives the iron and manganese reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Affords a considerable white incrustation of ZnO.

(8) Special reactions. Gives a strong manganese reaction with nitre and carbonate of soda.

* * * * *

Mineral. Ilmenite

Formula. [...Ti=] and [...Fe=].

Behavior

(1) in glass-bulb. --

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. V. In reducing flame fuses on edges and becomes magnetic.

(5) in borax. Gives the iron reaction.

(6) in mic. salt. In oxidizing flame exhibits the iron reaction. In reducing flame assumes a deep brownish red color.

(7) with carb. soda. --

(8) Special reactions. --

* * * * *

Mineral. Chromic iron

Formula. [.Fe][...Cr=].

Behavior

(1) in glass-bulb. --

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. As the preceding.

(5) in borax. Dissolves slowly and gives the chromium reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. On platinum foil with nitre and carbonate of soda affords a yellow mass of chromate of potassa.

(8) Special reactions. --

* * * * *

Mineral. Lievrite

Formula. 3([.Fe][.Ca])^{3}[...Si] + 2[...Fe=][...Si].

Behavior

(1) in glass-bulb. Occasionally gives off some water and turns black.

(2) in open tube. --

(3) on charcoal. Fuses to a black globule, which in the reducing flame becomes magnetic.

(4) in forceps. I. In reducing flame is magnetic.

(5) in borax. Gives the iron reaction.

(6) in mic. salt. Gives the iron and silica reactions.

(7) with carb. soda. Fuses to a black opaque bead.

(8) Special reactions. Generally gives the manganese reaction with nitre and carbonate of soda.

* * * * *

Mineral. Chloropal

Formula. [...Fe=][...Si]^{2} + 3[.H].

Behavior

(1) in glass-bulb. Decrepitates more or less, gives off much water and turns black.

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. V. Loses color and turns black.

(5) in borax. Gives the iron reaction.

(6) in mic. salt. Gives the iron and silica reaction.

(7) with carb. soda. Fuses to a transparent green glass.

(8) Special reactions. --

* * * * *

Mineral. Green earth

Formula. [...Si],[.Fe],[...Al=],[.Na],[.K],[.H], etc.

Behavior

(1) in glass-bulb. Gives off water and becomes darker in color.

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. V. In reducing flame fuses on edges and colors the outer flame yellow ([.Na]) or violet ([.K]).

(5) in borax. As the preceding.

(6) in mic. salt. As the preceding.

(7) with carb. soda. Forms a slaggy mass.

(8) Special reactions. --

* * * * *

Mineral. Siderite

Formula. [.Fe][..C].

Behavior

(1) in glass-bulb. Occasionally decrepitates. Gives off CO^{2} and turns black and magnetic.

(2) in open tube. --

(3) on charcoal. As in glass bulb.

(4) in forceps. Behaves similarly to the magnetic oxide.

(5) in borax. Gives the iron and manganese reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Behaves as an oxide. With nitre and carbonate of soda on platinum generally gives the manganese reaction.

(8) Special reactions. In acid dissolves with effervescense.

* * * * *

Mineral. Copperas

Formula. [.Fe][...S] + 7[.H].

Behavior

(1) in glass-bulb. Gives off water, and, when strongly heated, SO^{2} and SO^{3}, which reddens litmus paper.

(2) in open tube. Evolves water and SO^{2}, which may be recognized by its odor.

(3) on charcoal. Loses water and SO^{2}, and is converted into [...Fe=].

(4) in forceps. Gives off H and SO^{2}, and then behaves as the magnetic oxide.

(5) in borax. The roasted mineral affords an iron reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Forms sulphide of sodium and oxide of iron. The former is absorbed into the charcoal, and if cut out and laid upon silver and moistened gives the S reaction.

(8) Special reactions. If dissolved in water, and a strip of silver-foil be introduced into the solution, the metal remains untarnished.

* * * * *

Mineral. Vivianite

Formula. [.Fe]^{3}[.....P] + 8[.H].

Behavior

(1) in glass-bulb. Gives off water.

(2) in open tube. --

(3) on charcoal. Froths up and then fuses to a grey metallic bead.

(4) in forceps. As on charcoal. Singes flame green ([.....P]).

(5) in borax. Gives the iron reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. In reducing flame becomes magnetic and fuses to a black saggy mass.

(8) Special reactions. --

* * * * *

Mineral. Iriphyline

Formula. ([.Fe][.Mn][.Li])^{3}[.....P].

Behavior

(1) in glass-bulb. Gives off water, having an alkaline reaction, and assumes a metallic lustre resembling graphite.

(2) in open tube. --

(3) on charcoal. Fuses readily to a black magnetic bead with a metallic lustre.

(4) in forceps. I. On platinum wire colors the flame crimson ([.Li]) and green ([.....P]), towards the point fuses to a black magnetic bead.

(5) in borax. Gives the iron and manganese reactions.

(6) in mic. salt. Gives the iron reaction which overpowers that of the manganese.

(7) with carb. soda. Forms an infusible porous mass, which under the reducing flame becomes magnetic.

(8) Special reactions. Gives the manganese reaction with nitre and carbonate of soda on platinum foil.

* * * * *

Mineral. Scorodite

Formula. [...Fe=][.....As] + 4[.H].

Behavior

(1) in glass-bulb. Evolves water.

(2) in open tube. Gives off water and AsO^{3}.

(3) on charcoal. Emits arsenical fume and in the reducing flame fuses to a magnetic mass having a metallic lustre.

(4) in forceps. I. As on charcoal. Colors the outer flame blue.

(5) in borax. The roasted mineral gives an iron reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. As alone on charcoal.

(8) Special reactions. Gives the arsenic reactions.

* * * * *

Mineral. Cube ore

Formula. [.Fe]^{3}[.....As] + [...Fe=]^{3}[.....As]^{2} + 18[.H].

Behavior

(1) in glass-bulb. Evolves much water.

(2) in open tube. As the preceding.

(3) on charcoal. As the preceding.

(4) in forceps. As the preceding.

(5) in borax. As the preceding.

(6) in mic. salt. As in borax.

(7) with carb. soda. As the preceding.

(8) Special reactions. As the preceding.

* * * * *

MANGANESE.

* * * * *

Mineral. Manganblende

Formula. MnS.

Behavior

(1) in glass-bulb. --

(2) in open tube. Gives off SO^{2} and becomes greyish green on surface.

(3) on charcoal. Is slowly roasted and converted into oxide.

(4) in forceps. V.

(5) in borax. The roasted mineral gives a strong manganese reaction.

(6) in mic. salt. In the unroasted state, dissolves with much ebullition and detonation due to elimination of sulphide of phosphorus. The bead then exhibits the characteristic violet color of manganese.

(7) with carb. soda. Forms a slaggy mass, which laid on silver and moistened, gives the sulphur reaction.

(8) Special reactions. --

* * * * *

Mineral. Pyrolusite

Formula. [..Mn].

Behavior

(1) in glass-bulb. Frequently gives off a small quantity of water and, when strongly heated, oxygen.

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. V.

(5) in borax. Gives the manganese reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Forms a slaggy mass.

(8) Special reactions. --

* * * * *

Mineral. Manganite

Formula. [...Mn=][.H].

Behavior

(1) in glass-bulb. Gives off much water.

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. V. Exfoliates slightly.

(5) in borax. As the preceding.

(6) in mic. salt. As in borax.

(7) with carb. soda. As the preceding.

(8) Special reactions. --

* * * * *

Mineral. Psilomelane

Formula. ([.Ba],[.Ca],[.Mg],[.K]) [..Mn] + [.H].

Behavior

(1) in glass-bulb. Gives off water and, when strongly heated, oxygen.

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. V. Colors flame faintly green(Ba) and red towards the point (Ca).

(5) in borax. As pyrolusite.

(6) in mic. salt. As in borax.

(7) with carb. soda. As pyrolusite.

(8) Special reactions. --

* * * * *

Mineral. Wad

Formula. [..Mn],[.Mn],[.H], also [...Fe=],[...Al=], [.Ba],[.Cu],[...Pb],[...Si], etc.

Behavior

(1) in glass-bulb. Gives off water.

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. V. Colors flame variously according to its composition.

(5) in borax. Gives the manganese reaction, more or less modified by the presence of other oxides.

(6) in mic. salt. As in borax.

(7) with carb. soda. As pyrolusite.

(8) Special reactions. Various according to composition. When strongly heated and then moistened has an alkaline reaction on red litmus paper.

* * * * *

Mineral. Rhodonite

Formula. [.Mn]^{3}[...Si]^{2}.

Behavior

(1) in glass-bulb. Gives off more or less water.

(2) in open tube. --

(3) on charcoal. Under a strong flame fuses to a brown opaque bead.

(4) in forceps. II. As on charcoal.

(5) in borax. In the oxidizing flame gives the manganese reaction. In reducing flame the iron reaction.

(6) in mic. salt. As in borax, but leaves an insoluble siliceous skeleton.

(7) with carb. soda. With a small quantity of the alkali fuses to a black bead. With a larger quantity forms a slag.

(8) Special reactions. --

* * * * *

Mineral. Diallogite

Formula. [.Mn][..C].

Behavior

(1) in glass-bulb. Frequently decrepitates and gives off more or less water.

(2) in open tube. --

(3) on charcoal. If strongly heated and moistened has an alkaline reaction on litmus paper due to the presence of Ca.

(4) in forceps. V. Frequently colors the flame slightly red.

(5) in borax. Gives the manganese and iron reactions.

(6) in mic. salt. As in borax.

(7) with carb. soda. Forms an infusible slag.

(8) Special reactions. In warm acid dissolves with much effervescence.

* * * * *

Mineral. Triplite

Formula. ([..Mn][.Fe])^{4}[.....P].

Behavior

(1) in glass-bulb. Generally gives off more or less water.

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. I. Colors the outer blowpipe flame green ([.....P]).

(5) in borax. Gives the manganese and iron reactions.

(6) in mic. salt. As in borax.

(7) with carb. soda. Forms an infusible mass.

(8) Special reactions. --

* * * * *

NICKEL AND COBALT.

* * * * *

Mineral. Millerite

Formula. NiS.

Behavior

(1) in glass-bulb. --

(2) in open tube. Evolves SO^{2}.

(3) on charcoal. Fuses with much ebullition to a magnetic bead.

(4) in forceps. --

(5) in borax. The roasted mineral gives a nickel reaction, slightly modified by small quantities of iron and copper.

(6) in mic. salt. As in borax.

(7) with carb. soda. Fuses to a slaggy mass, which on silver gives the sulphur reaction.

(8) Special reactions. --

* * * * *

Mineral. Coppernickel

Formula. Ni^{2}As.

Behavior

(1) in glass-bulb. Gives off a little AsO^{3}.

(2) in open tube. Gives off much AsO^{3} and some SO^{2} and falls to powder.

(3) on charcoal. Fuses to a magnetic bead, with the evolution of arsenic, which colors the flame blue.

(4) in forceps. --

(5) in borax. The arsenical bead obtained by fusing the mineral on charcoal, if fused upon the same support with borax successively added and removed, gives firstly an iron reaction, then cobalt if present, and lastly nickel.

(6) in mic. salt. If the residual bead which has been treated with borax be further treated with microcosmic salt, the nickel reaction will be obtained and sometimes a slight copper reaction.

(7) with carb. soda. --

(8) Special reactions. Affords a sublimate of metallic arsenic when treated with cyanide of potassium.

* * * * *

Mineral. Smaltine

Formula. CoAs.

Behavior

(1) in glass-bulb. When strongly heated generally evolves metallic arsenic.

(2) in open tube. Gives a crystalline sublimate of AsO^{3}. Also some SO^{2}.

(3) on charcoal. Gives off fumes of arsenic, and fuses to a dark grey magnetic bead, very brittle, colors flame blue.

(4) in forceps. --

(5) in borax. As the preceding, but the cobalt being in large excess requires some time for its perfect oxidation, before the nickel reaction is exhibited.

(6) in mic. salt. Gives the cobalt reaction, and after the cobalt has been, removed that of nickel.

(7) with carb. soda. --

(8) Special reactions. As the preceding.

* * * * *

Mineral. Glance cobalt

Formula. CoS^{2} + CoAs.

Behavior

(1) in glass-bulb. --

(2) in open tube. As the preceding, but gives off more SO^{2}.

(3) on charcoal. Gives off S and As, and fuses to a magnetic bead. Colors flame blue.

(4) in forceps. --

(5) in borax. Gives a cobalt and slight iron reaction when treated as the preceding minerals.

(6) in mic. salt. As in borax.

(7) with carb. soda. Gives a sulphur reaction of silver.

(8) Special reactions. As the preceding.

* * * * *

Mineral. Nickel glance

Formula. NiS^{2} + NiAs.

Behavior

(1) in glass-bulb. Decrepitates and gives an orange colored sublimate of AsS^{2}.

(2) in open tube. As the preceding.

(3) on charcoal. As the preceding.

(4) in forceps. --

(5) in borax. As copper nickel.

(6) in mic. salt. Gives the nickel reaction occasionally somewhat obscured by cobalt.

(7) with carb. soda. As the preceding.

(8) Special reactions. As copper nickel.

* * * * *

Mineral. Ulmannite

Formula. NiS^{2} + Ni(AsSb)^{2}.

Behavior

(1) in glass-bulb. Gives a slight white sublimate of SbO^{3} and more or less AsS^{3}.

(2) in open tube. Gives off thick fumes of SbO^{3} and SbO^{5} with AsO^{3} and SO^{2}.

(3) on charcoal. As glance cobalt, but accompanied by dense fumes of SbO^{3}.

(4) in forceps. --

(5) in borax. As copper nickel.

(6) in mic. salt. As the preceding.

(7) with carb. soda. As the preceding.

(8) Special reactions. As copper nickel generally, but arsenic is not always present.

* * * * *

Mineral. Cobalt pyrites

Formula. ([,Co][,Ni][,Fe]) ([,,,Co=][,,,Ni=][,,,Fe=]).

Behavior

(1) in glass-bulb. When strongly heated gives off sulphur and becomes brown.

(2) in open tube. Gives off much SO^{2} and a small quantity of AsO^{3}.

(3) on charcoal. In the reducing flame small fragments fuse with the evolution of sulphur to a magnetic bead having a bronze colored fracture.

(4) in forceps. --

(5) in borax. In the oxidizing flame on charcoal gives a violet colored glass. In the reducing flame the nickel is reduced and may collected in a gold bead. When the nickel is removed, the glass exhibits a slight iron reaction while warm.

(6) in mic. salt. As in borax, but the reduction of the nickel is more difficult than in the latter flux.

(7) with carb. soda. As glance cobalt.

(8) Special reactions. As copper nickel, but the amount of arsenic is usually very small.

* * * * *

Mineral. Emerald nickel

Formula. [.Ni]^{3}[..C] + 6[.H].

Behavior

(1) in glass-bulb. Gives off much water and turns black.

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. --

(5) in borax. Dissolves with much effervescence and gives the nickel reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Forms a slaggy mass.

(8) Special reactions. In warm dilute HCl dissolves with much effervescence.

* * * * *

Mineral. Cobalt Bloom

Formula. [.Co]^{3}[.....As] + 8[.H].

Behavior

(1) in glass-bulb. Gives off water.

(2) in open tube. --

(3) on charcoal. Evolves arsenical fumes and in the reducing flame fuses to a dark grey bead of arsenide of cobalt.

(4) in forceps. In the point of the blue flame fuses and colors the outer flame blue (As).

(5) in borax. Gives the cobalt reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. --

(8) Special reactions. Gives off arsenic with cyanide of potassium in glass tube.

* * * * *

Mineral. Earthy cobalt

Formula. [.Mn],[.Co],[.Cu],[.Fe],[.H], etc.

Behavior

(1) in glass-bulb. Gives off water.

(2) in open tube. --

(3) on charcoal. Emits a slight smell of arsenic, but does not fuse.

(4) in forceps. Colors the flame blue.

(5) in borax. In oxidizing flame gives the cobalt reaction which obscures those of [.Mn], [.Cu], etc. In reducing flame occasionally gives the [.Cu] reaction.

(6) in mic. salt. As in borax. If a saturated bead be treated on charcoal with tin in the reducing flame for a few seconds, the [.Cu] reaction is sometimes obtained.

(7) with carb. soda. Forms an infusible mass.

(8) Special reactions. With carbonate of soda and nitre on platinum foil, gives a strong manganese reaction.

* * * * *

ZINC.

* * * * *

Mineral. Zincblende

Formula. ZnS.

Behavior

(1) in glass-bulb. Decrepitates strongly.

(2) in open tube. Evolves SO and becomes white or yellow if containing iron.

(3) on charcoal. V. In the reducing flame incrusts the charcoal with ZnO; also with CdO, if that metal be present.

(4) in forceps. --

(5) in borax. The roasted mineral gives a zinc reaction, and sometimes a slight iron reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. As alone on charcoal. Moreover colors the flame blue. The fused alkali gives a S reaction on silver.

(8) Special reactions. --

* * * * *

Mineral. Red oxide of zinc

Formula. [.Zn].

Behavior

(1) in glass-bulb. --

(2) in open tube. --

(3) on charcoal. In the reducing flame forms a thin incrustation of oxide of zinc on the charcoal.

(4) in forceps. V.

(5) in borax. Generally gives a manganese and slight iron reaction in addition to that of zinc.

(6) in mic. salt. As in borax.

(7) with carb. soda. On charcoal, forms a thick incrustation of ZnO.

(8) Special reactions. With carbonate of soda and nitre on platinum foil gives manganese reaction.

* * * * *

Mineral. Electric calamine

Formula. 2[.Zn]^{3}[...Si] + 3[.H]

Behavior

(1) in glass-bulb. Gives off water and becomes white and opaque.

(2) in open tube. --

(3) on charcoal. --

(4) in forceps. V.

(5) in borax. Dissolves to a clear glass, which cannot be rendered opaque by the intermittent flame.

(6) in mic. salt. Dissolves to a clear glass, which becomes opaque on cooling. Silica remains insoluble.

(7) with carb. soda. With carbonate of soda alone is infusible. With 2 parts of alkali and 1 of borax fuses to a glass and sets free [.Zn], which incrusts the charcoal.

(8) Special reactions. --

* * * * *

Mineral. Calamine

Formula. [.Zn][..C].

Behavior

(1) in glass-bulb. Gives off CO^{2} and becomes opaque.

(2) in open tube. --

(3) on charcoal. As the red oxide. Sometimes also gives a lead incrustation.

(4) in forceps. V.

(5) in borax. Gives a zinc reaction and frequently an iron and manganese reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Forms a thick incrustation of zinc, sometimes also of [.Pb] and [.Co].

(8) Special reactions. Dissolves with much effervescence in cold acid.

* * * * *

BISMUTH.

* * * * *

Mineral. Native bismuth

Formula. Bi.

Behavior

(1) in glass-bulb. --

(2) in open tube. Fuses and is converted into a yellow oxide.

(3) on charcoal. Fuses to a bead and incrusts the charcoal with oxide.

(4) in forceps. --

(5) in borax. The oxide formed upon charcoal gives the bismuth reactions.

(6) in mic. salt. As in borax.

(7) with carb. soda. --

(8) Special reactions. --

* * * * *

Mineral. Bismuthine

Formula. BiS.

Behavior

(1) in glass-bulb. --

(2) in open tube. Fuses with ebullition and gives of S and SO^{2}.

(3) on charcoal. Fuses with much spirting and in the reducing flame yields a metallic bead and incrusts the charcoal with oxide.

(4) in forceps. --

(5) in borax. The oxide obtained upon charcoal gives the bismuth reactions.

(6) in mic. salt. As in borax.

(7) with carb. soda. As alone on charcoal. The fused alkali gives the sulphur reaction on silver.

(8) Special reactions. --

* * * * *

Mineral. Bismuthblende

Formula. [...Bi=]^{2}[...Si]^{3}.

Behavior

(1) in glass-bulb. Turns yellow and, when strongly heated, fuses.

(2) in open tube. --

(3) on charcoal. Fuses with ebullition to a brown globule forming an incrustation of [...Bi=] on the charcoal.

(4) in forceps. I. Fuses with ease to a yellow bead, coloring the outer flame bluish green, especially if moistened with HCl. This color is due to [.....P].

(5) in borax. Gives the bismuth and also an iron reaction.

(6) in mic. salt. As in borax, but leaves a silicious skeleton.

(7) with carb. soda. Fuses to a yellow mass. The bismuth is then reduced to the metallic state and partially volatilized, incrusting the charcoal beyond.

(8) Special reactions. --

* * * * *

Mineral. Tetradymite

Formula. Bi, Te, S.

Behavior

(1) in glass-bulb. Occasionally decrepitates and then fuses, forming a greyish white sublimate immediately above the mineral fragment.

(2) in open tube. Fuses and gives off white fumes, part of which pass up the tube and part deposit immediately above the mineral. This latter if heated fuses to clear drops (TeO^{3}). The mineral residue becomes surrounded by fused [...Bi=], characterized by its yellow color.

(3) on charcoal. Fuses to a metallic bead, colors the outer flame bluish green (Te and Se) and incrusts the charcoal around with the orange [...Bi=], beyond which is a white incrustation partly consisting of [...Te].

(4) in forceps. --

(5) in borax. The yellow oxide obtained upon charcoal gives the bismuth reaction, and the white incrustation of bismuth and telluric acid.

(6) in mic. salt. As in borax.

(7) with carb. soda. In the reducing flame yields a bead of metallic bismuth, part of which is part of the tellurium volatilized and incrusts the charcoal around.

(8) Special reactions. The fused alkaline mass gives the sulphur reaction on silver. Also gives the tellurium reaction with charcoal and carbonate of soda.

* * * * *

LEAD.

* * * * *

Mineral. Galena

Formula. PbS.

Behavior

(1) in glass-bulb. Generally decrepitates and gives off a small quantity of sulphur.

(2) in open tube. Gives off SO^{2}, and when strongly heated, a white sublimate of [.Pb], [.S].

(3) on charcoal. Fuses and is reduced affording a bead of metallic lead, and forming an incrustation of PbO on the charcoal. Colors the outer flame blue.

(4) in forceps. --

(5) in borax. The oxide formed upon charcoal gives the lead reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. As alone on charcoal. The fused alkali gives a sulphur reaction on silver.

(8) Special reactions. --

* * * * *

Mineral. Clausthalite

Formula. PbSe.

Behavior

(1) in glass-bulb. Decrepitates slightly.

(2) in open tube. Forms a sublimate of selenium, which is grey when thickly deposited, and red when thin.

(3) on charcoal. Gives off fumes smelling strongly of selenium and coloring the flame blue. In the reducing flame fuses partially and incrusts the charcoal with Se and PbO. After some time a black infusible mass alone remains.

(4) in forceps. --

(5) in borax. The infusible residue obtained upon charcoal gives an iron and sometimes copper and cobalt reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. With carbonate of soda, oxalate of potash yields a metallic bead, the fused alkali laid upon silver and moistened produces a stain similar to that produced by sulfur.

(8) Special reactions. --

* * * * *

Mineral. Jamesonite

Formula. [,Pb]^{3}[,,,Sb]^{2}.

Behavior

(1) in glass-bulb. Fuses and gives off some sulphur, sulphide of antimony and antimony which condense in the neck of the bulb.

(2) in open tube. Fuses and emits dense white fumes of SbO^{3}, which pass off and redden blue litmus paper.

(3) on charcoal. Fuses with great ease evolving much SbO^{3} and PbO, which incrusts the charcoal around the mineral. When the fumes have ceased, a small bead of metallic lead remains.

(4) in forceps. --

(5) in borax. The yellow incrustation formed upon charcoal gives the reaction of lead, and the white those of antimony.

(6) in mic. salt. As in borax.

(7) with carb. soda. As alone on charcoal. The fused alkali gives the sulphur reaction on silver.

(8) Special reactions. --

* * * * *

Mineral. Minium

Formula. Pb^{3}O^{4}.

Behavior

(1) in glass-bulb. --

(2) in open tube. --

(3) on charcoal. Is reduced first to litharge (PbO) and then to metallic lead which forms the usual incrustation.

(4) in forceps. Colors the outer flame blue.

(5) in borax. Gives the lead reactions.

(6) in mic. salt. As in borax.

(7) with carb. soda. As alone on charcoal.

(8) Special reactions. --

* * * * *

Mineral. Mendipite

Formula. PbCl + 2PbO.

Behavior

(1) in glass-bulb. Decrepitates slightly and assumes a yellow color.

(2) in open tube. --

(3) on charcoal. Fuses readily and is reduced to metallic lead with the evolution of acid fumes. Forms a white incrustation of PbCl, and a yellow one of PbO.

(4) in forceps. As the preceding.

(5) in borax. As the preceding.

(6) in mic. salt. As in borax.

(7) with carb. soda. As alone on charcoal.

(8) Special reactions. Gives the chlorine reaction with CuO and microcosmic salt.

* * * * *

Mineral. Cerusite

Formula. [.Pb][..C].

Behavior

(1) in glass-bulb. Decrepitates, gives off CO^{2}, turns yellow and fuses.

(2) in open tube. --

(3) on charcoal. Is reduced to metallic lead, incrusting the charcoal around with PbO.

(4) in forceps. As the preceding.

(5) in borax. Gives the lead reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. As alone on charcoal.

(8) Special reactions. In nitric acid dissolves with much effervescence.

* * * * *

Mineral. Anglesite

Formula. [.Pb][...S].

Behavior

(1) in glass-bulb. Decrepitates and gives off a small quantity of water.

(2) in open tube. --

(3) on charcoal. In the oxidizing flame fuses to a clear bead, which becomes opaque on cooling. In reducing flame is reduced with much ebullition to a metallic bead and incrusts the charcoal around with PbO.

(4) in forceps. As the preceding.

(5) in borax. Gives the lead reaction and occasionally a slight iron and manganese reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Is reduced yielding a metallic lead bead. The fused alkaline mass gives a sulphur reaction on silver.

(8) Special reactions. --

* * * * *

Mineral. Pyromorphite

Formula. PbCl + 3[.Pb]^{3}[.....P].

Behavior

(1) in glass-bulb. Decrepitates, and when strongly heated for some time, gives a slight white sublimate of PbCl.

(2) in open tube. --

(3) on charcoal. In oxidizing flame fuses to a bead having a crystalline surface on cooling, and forms a thin film of PbCl on the charcoal In reducing flame fuses without reduction and on cooling assumes a polyhedral form. Incrusts the charcoal slightly with PbO.

(4) in forceps. Fuses and colors the flame blue.

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. Is reduced yielding a metallic bead and incrusting the charcoal with PbO.

(8) Special reactions. Gives the chlorine reaction with microcosmic salt and CuO. Also the phosphoric acid reactions.

* * * * *

Mineral. Mimetene

Formula. PbCl+ 3[.Pb]^{3}[.....As]

Behavior

(1) in glass-bulb. As the preceding.

(2) in open tube. --

(3) on charcoal. Fuses, but less easily than the preceding, gives off AsO^{3} and incrusts the charcoal with PbCl. Finally is reduced to a metallic bead and forms an incrustation of PbO.

(4) in forceps. As the preceding.

(5) in borax. The oxide formed on charcoal gives the lead reactions.

(6) in mic. salt. As in borax.

(7) with carb. soda. As the preceding.

(8) Special reactions. Gives the chlorine reaction.

* * * * *

Mineral. Vanadinite

Formula. PbCl + 3[.Pb]^{3}[...V]?

Behavior

(1) in glass-bulb. As pyromorphite.

(2) in open tube. --

(3) on charcoal. The powdered mineral fuses fuses to a black shining mass, which in the reducing flame affords a metallic bead. Incrusts the charcoal first with a white film of PbCl and afterwards with PbO.

(4) in forceps. As pyromorphite.

(5) in borax. Dissolves readily to a clear glass, which, in the oxidizing flame, is yellow, while hot, and colorless when cold. In reducing flame becomes opaque, and on cooling green.

(6) in mic. salt. In oxidizing flame is yellow while hot, becoming paler on cooling. In reducing flame brown while warm, and emerald green when cold.

(7) with carb. soda. On platinum wire fuses to a yellow bead, which is crystalline on cooling. On charcoal yields a button of metallic lead.

(8) Special reactions. With microcosmic salt and CuO, gives the chlorine reaction. If fused in a platinum spoon with from 3 to 4 times its volume of [.K],[...S]^{2} it forms a fluid yellow mass having an orange color when cold.

* * * * *

Mineral. Crocoisite

Formula. [.Pb][...Cr].

Behavior

(1) in glass-bulb. Decrepitates violently and assumes a dark color.

(2) in open tube. --

(3) on charcoal. Fuses and detonates yielding Cr^{2}O^{3} and metallic lead, and forming an incrustation of PbO on the charcoal.

(4) in forceps. As pyromorphite.

(5) in borax. Dissolves readily and colors the glass yellow while warm, and green when cold. (See Chromium reaction.)

(6) in mic. salt. As in borax.

(7) with carb. soda. On platinum foil gives a dark yellow mass, which becomes paler on cooling. On charcoal yields a metallic button.

(8) Special reactions. Treated as above with [.K],[...S]^{2} forms a violet colored mass, which on solidifying becomes reddish and on cooling pale grey.

* * * * *

Mineral. Molybdate of lead

Formula. [.Pb][...M].

Behavior

(1) in glass-bulb. As the preceding.

(2) in open tube. --

(3) on charcoal. Fuses and is partly absorbed into the charcoal leaving a globule of metallic lead, which is partially oxidized and incrusts the charcoal.

(4) in forceps. As pyromorphite.

(5) in borax. Dissolves readily and gives the molybdena reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Yields metallic lead.

(8) Special reactions. Fused as above with [.K],[...S]^{2} forms a yellow mass, which becomes white on cooling. If this be dissolved in water and a piece of zinc introduced into the solution, the latter becomes blue.

* * * * *

Mineral. Scheeletine

Formula. [.Pb][...W].

Behavior

(1) in glass-bulb. Decrepitates more or less.

(2) in open tube. --

(3) on charcoal. Fuses to a bead incrusting the charcoal with PbO. The bead on cooling is crystalline and has a dark metallic surface.

(4) in forceps. As pyromorphite.

(5) in borax. Dissolves to a clear colorless glass, which in the reducing flame becomes yellow, and on cooling grey and opaque.

(6) in mic. salt. Dissolves to a clear colorless glass, which in the reducing flame assumes a dusky blue color. After a time becomes opaque.

(7) with carb. soda. As the preceding.

(8) Special reactions. With carbonate of soda and nitre gives the manganese reaction.

* * * * *

COPPER.

* * * * *

Mineral. Native Copper

Formula. Cu.

Behavior

(1) in glass-bulb. --

(2) in open tube. --

(3) on charcoal. Fuses to a brilliant metallic bead, which on cooling becomes covered with a coating of black oxide.

(4) in forceps. Fuses and colors the outer flame blue.

(5) in borax. In the oxidizing flame dissolves and then gives the copper reactions.

(6) in mic. salt. As in borax.

(7) with carb. soda. --

(8) Special reactions. --

* * * * *

Mineral. Vitreous Copper

Formula. Cu^{2}S.

Behavior

(1) in glass-bulb. --

(2) in open tube. Evolves SO^{2} and, when pulverized and gently heated for some time is converted into CuO.

(3) on charcoal. Fuses to a bead, which spirts considerably and gives off SO^{2}. When pulverized and gently roasted, is converted into CuO.

(4) in forceps. --

(5) in borax. The roasted mineral gives the copper reaction, and sometimes also a slight iron-reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. In the reducing flame is decomposed, forming NaS and metallic copper. If the former be cut out and laid upon silver, it gives the sulfur reaction.

(8) Special reactions. --

* * * * *

Mineral. Copper pyrites

Formula. [,Cu=][,,,Fe=].

Behavior

(1) in glass-bulb. Decrepitates, sometimes gives a sublimate of sulphur and becomes bronze colored on the surface.

(2) in open tube. Evolves SO^{2} and is finally converted into a dark red mixture of Fe^{2}O^{3} and CuO.

(3) on charcoal. Fuses readily with much ebullition and is magnetic on cooling.

(4) in forceps. --

(5) in borax. As the preceding; but when the copper has been removed by reducing on charcoal, the bead shows a strong iron color.

(6) in mic. salt. As the preceding, but the color in the oxidizing flame is green, owing to the presence of iron.

(7) with carb. soda. Yields a bead of metallic copper and some magnetic oxide of iron which remains on the charcoal. The fused gives a sulphur reaction on silver.

(8) Special reactions. --

* * * * *

Mineral. Fahlerz

Formula. ([,Cu=][,Ag][,Fe][,Zn])^{4} ([,,,Sb][,,,As]).

Behavior

(1) in glass-bulb. Sometimes decrepitates, fuses, and when very strongly heated, gives a red sublimate of [,,,Sb] with [...Sb], also sometimes a black sublimate of [,Hg] and occasionally [,,,As].

(2) in open tube. Fuses and gives off thick fumes of SbO^{3} and SO^{2}, also generally AsO^{3}, leaving a black infusible residue. If Hg be present, it is sublimed and condenses in the tube in small drops.

(3) on charcoal. Fuses to a bead, which fumes strongly and incrusts the charcoal with SbO^{3}, and sometimes ZnO, which cannot be volatilized. Emits a strong smell of arsenic.

(4) in forceps. --

(5) in borax. The residue obtained on charcoal thoroughly roasted gives a copper reaction, and when the latter has been removed by reduction upon charcoal, an iron reaction.

(6) in mic. salt. As in the preceding.

(7) with carb. soda. With this flux and a little borax yields a bead of metallic copper; on silver, the alkaline mass gives a sulphur reaction.

(8) Special reactions. If the copper bead obtained by fusing upon carbonate of soda be cupelled with assay lead, a silver bead will be obtained. Or if dissolved in nitric acid and a drop or two of HCl added, a white precipitate of AgCl will be formed, which may be collected and reduced with carbonate of soda upon charcoal.

* * * * *

Mineral. Tennatite

Formula. ([,Cu=][,Fe=])^{4}[,,,As].

Behavior

(1) in glass-bulb. Decrepitates occasionally and gives a red sublimate of [,,,As].

(2) in open tube. Evolves [..S] and [...As], which condense and form a white sublimate.

(3) on charcoal. Fuses to a magnetic bead giving of arsenical and sulphurous fumes.

(4) in forceps. --

(5) in borax. As the preceding.

(6) in mic. salt. As the preceding.

(7) with carb. soda. Yields a copper bead and metallic iron in the form of a dark grey powder. The fused alkali gives the sulphur reaction.

(8) Special reactions. --

* * * * *

Mineral. Bournonite

Formula. ([,Pb]^{2}[,Cu=])[,,,Sb].

Behavior

(1) in glass-bulb. Decrepitates giving off sulfur and, when strongly heated, [,,,Sb] and [...Sb].

(2) in open tube. Evolves thick white fumes of [...Sb],[.....Sb] and [.Pb][...Sb]. Also [.S].

(3) on charcoal. Fuses readily and incrusts the charcoal with [...Sb] and [.Pb] leaving a dark colored bead.

(4) in forceps. --

(5) in borax. If the bead obtained on charcoal be fused on that support in the reducing flame with borax, a slight iron reaction is obtained, and after a time a copper reaction.

(6) in mic. salt. As with borax.

(7) with carb. soda. Yields a bead of metallic copper and lead and incrusts the charcoal with [...Sb] and [.Pb]. The alkaline mass laid on silver and moistened gives the sulphur reaction.

(8) Special reactions. --

* * * * *

Mineral. Red oxide of copper

Formula. Cu^{2}O

Behavior

(1) in glass-bulb. --

(2) in open tube. Is converted into the black oxide CuO.

(3) on charcoal. In the reducing flame is reduced, forming a bead of metallic copper.

(4) in forceps. Fuses and colors the the flame emerald green, or if previously moistened with HCl, blue.

(5) in borax. Gives the copper reaction.

(6) in mic. salt. As with borax.

(7) with carb. soda. Is reduced to a bead of metallic copper.

(8) Special reactions. --

* * * * *

Mineral. Atacamite

Formula. CuCl + 3[.Cu] + 6[.H].

Behavior

(1) in glass-bulb. Gives off much water, having an acid reaction, on test paper, and forms a light grey sublimate of CuCl.

(2) in open tube. --

(3) on charcoal. Fuses, colors the flame blue, forms a brown and a pale grey incrustation on the charcoal, and is reduced to metallic copper, leaving a small quantity of slag.

(4) in forceps. Fuses and colors the outer flame intensely blue and green towards the point.

(5) in borax. Gives the copper reactions.

(6) in mic. salt. As with borax.

(7) with carb. soda. Is reduced, yielding a bead of metallic copper.

(8) Special reactions. --

* * * * *

Mineral. Dioptase

Formula. [.Cu]^{3}[...Si]^{2} + 3[.H].

Behavior

(1) in glass-bulb. Gives off water and turns black.

(2) in open tube. --

(3) on charcoal. In the oxidizing flame becomes black. In the reducing flame red.

(4) in forceps. V. Colors the outer flame intensely green.

(5) in borax. Gives the copper reactions.

(6) in mic. salt. As with borax. The silica remains undissolved.

(7) with carb. soda. With a small quantity of carbonate of soda fuses to a bead, which on cooling is opaque and has a red fracture. With more alkali forms a slag, containing little beads of reduced copper.

(8) Special reactions. --

* * * * *

Mineral. Malachite

Formula. [.Cu]^{2}[..C] + [.H].

Behavior

(1) in glass-bulb. Gives off water and turns black.

(2) in open tube. --

(3) on charcoal. Fuses to a bead with a strong flame is reduced to metallic copper.

(4) in forceps. Fuses and colors the outer flame brilliantly green.

(5) in borax. Gives the copper reaction.

(6) in mic. salt. As with borax.

(7) with carb. soda. Yields metallic copper.

(8) Special reactions. Dissolves in HCl with much effervescence.

* * * * *

Mineral. Blue vitriol

Formula. [.Cu][...S] + 5[.H].

Behavior

(1) in glass-bulb. Intumesces, gives off water and becomes white.

(2) in open tube. Strongly heated is decomposed, given off SO^{2} and being converted into CuO.

(3) on charcoal. As in the glass-bulb. Then fuses, coloring the outer flame green, and is reduced to metallic copper and [,Cu=].

(4) in forceps. Fuses and colors the outer flame blue.

(5) in borax. The roasted mineral gives copper reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Yields metallic copper. The alkaline mass laid on silver gives S reaction.

(8) Special reactions. Gives the sulphuric acid reaction.

* * * * *

Mineral. Libethenite

Formula. [.Cu]^{4}[.....P] + 2[.H].

Behavior

(1) in glass-bulb. Gives off water and turns black.

(2) in open tube. --

(3) on charcoal. Gradually heated, turns black and fuses to a bead, having a core of metallic copper.

(4) in forceps. Fuses but does not color the flame distinctly. On cooling is black and crystalline.

(5) in borax. Gives the copper reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. With much of the alkali is decomposed, yielding metallic copper. With small portions successively added first fuses and then intumesces, fuses with a strong flame, and is then absorbed into the charcoal, leaving metallic copper.

(8) Special reactions. Gives the phosphoric acid reaction.

* * * * *

Mineral. Olivenite

Formula. [.Cu]^{4}([.....As][.....P]) + [.H].

Behavior

(1) in glass-bulb. Gives off water.

(2) in open tube. --

(3) on charcoal. Fuses with detonation and the evolution of arsenical fumes to a brittle regulus, brown externally and having a white fracture.

(4) in forceps. Fuses and colors the outer flame green. On cooling has a crystalline surface.

(5) in borax. Gives the copper reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. Is reduced, yielding metallic copper.

(8) Special reactions. Gives the arsenic reactions.

* * * * *

ANTIMONY.

* * * * *

Mineral. Native antimony

Formula. Sb.

Behavior

(1) in glass-bulb. Fuses and, when strongly heated, volatilizes being redeposited in the tube as a dark grey sublimate.

(2) in open tube. Fuses and gives off dense white fumes, which are partly redeposited on the tube. Sometimes also gives off arsenical fumes in small quantity.

(3) on charcoal. Fuses and gives off dense white fumes, which thickly incrust the charcoal and color the flame blue immediately beyond the assay.

(4) in forceps. --

(5) in borax. The oxide formed upon charcoal gives the antimony reactions.

(6) in mic. salt. As in borax.

(7) with carb. soda. --

(8) Special reactions. The incrustation on the charcoal, if treated with nitrate of cobalt assumes the characteristic green color.

* * * * *

Mineral. Grey antimony

Formula. SbS^{3}.

Behavior

(1) in glass-bulb. Fuses readily and occasionally gives off a small quantity of sulphur. Strongly heated forms a brown sublimate of SbS^{3} and SbO^{3}.

(2) in open tube. Fuses and gives off SO^{2}, which passes off up the tube, and dense white fumes of SbO^{3} and SbO^{5} which are partly deposited in the tube.

(3) on charcoal. Fuses and is partly absorbed by the charcoal and partly volatilized, incrusting the charcoal with the characteristic white oxides. Colors the flame blue.

(4) in forceps. --

(5) in borax. As the preceding.

(6) in mic. salt. As in borax.

(7) with carb. soda. Fuses and is reduced, yielding metallic antimony, which behaves as the preceding mineral upon charcoal. The alkaline mass gives the sulphur reaction.

(8) Special reactions. As the preceding.

* * * * *

Mineral. Antimony blende

Formula. [,,,Sb]^{2} + [...Sb].

Behavior

(1) in glass-bulb. Fuses easily, gives off first SbO^{3} and afterwards an orange colored sublimate. Strongly heated, is decomposed and gives a black sublimate, which becomes brown on cooling.

(2) in open tube. As the preceding.

(3) on charcoal. As the preceding.

(4) in forceps. --

(5) in borax. As native antimony.

(6) in mic. salt. As in borax.

(7) with carb. soda. As the preceding.

(8) Special reactions. As native antimony.

* * * * *

Mineral. White antimony

Formula. SbO^{3}.

Behavior

(1) in glass-bulb. Is sublimed and recondensed in the neck of the tube.

(2) in open tube. As in the glass-bulb.

(3) on charcoal. Fuses with the evolution of dense white fumes, which incrust the surface of the charcoal. In the reducing flame is partly reduced, yielding metallic antimony. Colors flame blue.

(4) in forceps. Fuses and is volatilized, coloring the outer flame blue.

(5) in borax. Gives the antimony reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. In the reducing flame is reduced, yielding metallic antimony.

(8) Special reactions. As native antimony.

* * * * *

ARSENIC.

* * * * *

Mineral. Native arsenic

Formula. As.

Behavior

(1) in glass-bulb. Sublimes without fusion and recondenses as a dark grey metallic sublimate, sometimes leaving a small residue.

(2) in open tube. If gently heated in a good current of air passes off as AsO^{3}, which is partly condensed as a white sublimate in the upper part of the tube.

(3) on charcoal. Passes off as AsO^{3}, which thinly incrusts the charcoal beyond the assay.

(4) in forceps. Colors the flame blue.

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. --

(8) Special reactions. --

* * * * *

Mineral. Realgar

Formula. AsS^{2}.

Behavior

(1) in glass-bulb. Fuses, enters into ebullition and is sublimed as a transparent red sublimate.

(2) in open tube. Gently heated passes off as SO^{2} and AsO^{3}, the latter of which is redeposited in the upper part of the tube.

(3) on charcoal. Fuses and passes off as arsenious and sulphurous acids.

(4) in forceps. Fuses and colors the flame blue.

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. As on charcoal, except that the S combines with the alkali forming NaS, which on silver gives the sulphur reaction.

(8) Special reactions. --

* * * * *

Mineral. Orpiment

Formula. AsS^{3}.

Behavior

(1) in glass-bulb. As the preceding, except that the sublimate is of a dark yellow color when cold.

(2) in open tube. As the preceding.

(3) on charcoal. As the preceding.

(4) in forceps. As the preceding.

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. As the preceding.

(8) Special reactions. --

* * * * *

Mineral. White arsenic

Formula. AsO^{3}.

Behavior

(1) in glass-bulb. Sublimes without fusion and re-condenses in white crystals.

(2) in open tube. --

(3) on charcoal. Sublimes and is partly recondensed on charcoal forming a white incrustation.

(4) in forceps. Colors the flame blue.

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. --

(8) Special reactions. Heated with charcoal in a glass-tube sealed at one end, is reduced and metallic arsenic sublimes.

* * * * *

MERCURY.

* * * * *

Mineral. Native mercury

Formula. Hg.

Behavior

(1) in glass-bulb. Volatilizes with little or no residue and recondenses in neck of bulb.

(2) in open tube. --

(3) on charcoal. Is volatilized.

(4) in forceps. --

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. --

(8) Special reactions. --

* * * * *

Mineral. Cinnabar

Formula. HgS.

Behavior

(1) in glass-bulb. Volatilizes sometimes leaving a slight earthy residue, and re-condenses as a black sulphide.

(2) in open tube. If gently heated is decomposed into metallic mercury, which volatilizes and recondenses in the upper part of the tube, and SO^{2}, which passes off as is easily recognized by its odor and bleaching properties.

(3) on charcoal. Is volatilized, generally leaving a small earthy residue.

(4) in forceps. --

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. With carbonate of soda and cyanide of potassium is decomposed and metallic mercury volatilized.

(8) Special reactions. When in the preceding experiment the mercury has been entirely dissipated, the alkaline residue laid on silver gives a sulphur reaction.

* * * * *

Mineral. Native amalgam

Formula. AgHg^{2}.

Behavior

(1) in glass-bulb. As native mercury, but leaves a residue of pure silver.

(2) in open tube. --

(3) on charcoal. The mercury volatilizes leaving the silver, which fuses to a bead, and, in the oxidizing flame, incrusts the charcoal with its characteristic oxide.

(4) in forceps. --

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. --

(8) Special reactions. --

* * * * *

SILVER.

* * * * *

Mineral. Native silver

Formula. Ag.

Behavior

(1) in glass-bulb. --

(2) in open tube. --

(3) on charcoal. Fuses and in a strong oxidizing flame forms an incrustation of dark brown oxide on the charcoal. If any antimony be present, it affords a crimson incrustation.

(4) in forceps. --

(5) in borax. Gives the silver reactions.

(6) in mic. salt. As in borax.

(7) with carb. soda. --

(8) Special reactions. --

* * * * *

Mineral. Antimonial silver

Formula. Ag^{2}Sb.

Behavior

(1) in glass-bulb. --

(2) in open tube. Gives off dense white fumes, which are partly deposited in the tube.

(3) on charcoal. Fuses, fumes strongly, forming a white incrustation, and when the antimony is nearly expelled a crimson one, a nearly pure silver bead remains.

(4) in forceps. --

(5) in borax. The incrustation formed on charcoal gives an antimony reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. As alone on charcoal.

(8) Special reactions. --

* * * * *

Mineral. Silver glance

Formula. AgS.

Behavior

(1) in glass-bulb. --

(2) in open tube. Gives off sulphurous acid.

(3) on charcoal. Gives off SO^{2} and is reduced to metallic silver. If impure, a small quantity of slag also remains.

(4) in forceps. --

(5) in borax. The residual slag (if any) obtained upon charcoal gives an iron reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. As alone on charcoal. The alkaline mass gives a sulphur reaction on polished silver.

(8) Special reactions. --

* * * * *

Mineral. Stephanite

Formula. [,Ag]^{6}[,,,Sb].

Behavior

(1) in glass-bulb. Decrepitates, fuses and gives a slight sublimate of sulphide of antimony.

(2) in open tube. Fuses and gives off SO^{2} and dense white antimonial fumes.

(3) on charcoal. Fuses and incrusts the charcoal with antimonious acid, leaving Ag with some antimony. If the flame be continued, a red incrustation is formed and finally a bead of pure silver remains surrounded by a small slag.

(4) in forceps. --

(5) in borax. The residual slag obtained on the charcoal gives an iron and copper reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. The silver is reduced and the antimony passes off in dense fumes. The fused alkali gives the sulphur reaction on silver.

(8) Special reactions. --

* * * * *

Mineral. Pyargyrite

Formula. [,Ag]^{3}[,,,Sb].

Behavior (1) in glass-bulb. Sometimes decrepitates, fuses readily, and, when strongly heated, gives a red sublimate of SbS^{3}.

(2) in open tube. As in the preceding.

(3) on charcoal. Fuses with much spirting and covers the charcoal with antimonial fumes. When the residual AgS is heated for some time in the oxidizing flame, a bead of pure silver is obtained.

(4) in forceps. --

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. As the preceding.

(8) Special reactions. --

* * * * *

Mineral. Proustite

Formula. [,Ag]^{3}[,,,As].

Behavior

(1) in glass-bulb. Fuses and at a low red heat affords a small sublimate of AsS^{3}.

(2) in open tube. Gradually heated it gives off AsO^{3} and SO^{2}. Sometimes also antimony fumes.

(3) on charcoal. As the preceding, except that a large quantity of AsO^{3} and but little SbO^{3} are given off.

(4) in forceps. --

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. As stephanite, except that much arsenic is given off and but little antimony.

(8) Special reactions. --

* * * * *

Mineral. Horn silver

Formula. AgCl.

Behavior

(1) in glass-bulb. Fuses, but undergoes no further change.

(2) in open tube. --

(3) on charcoal. Fuses readily in the oxidizing flame. In the reducing flame is slowly reduced yielding metallic silver.

(4) in forceps. --

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. Is rapidly reduced to metallic silver.

(8) Special reactions. If cut up into small pieces mixed with oxide of copper and then heated before the oxidizing flame upon charcoal, it colors the flame blue.

THE END.

* * * * *

Transcriber's Notes:

Text italicized in the original book is surrounded by '_'.

This book had many columnar tables, often split across pages. These have been transformed in data sheets for readability.

The notation ^{#} is used for superscripted numbers, indicating the composition of the various chemical compounds.

Some of the element symbols were differenced by markings that were not defined in the book, but are supposed to be valence markings. These have been transcribed as follows:

'.' or ',' above element symbol [?.Symbol] or [?,Symbol] '-' above element symbol [=Symbol] '-' through element symbol [Symbol=] ... So [...Al] where the original text had Al _ [=M] where the original text had M ,,, [,,,Sb] where the original text had Sb ... [...Fe=] where the original text had Fe, line through the Fe.