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Mineralogical Chemistry.

Origin of Hydrogen Chloride, Sulphurous Anhydride, and Iodine in the Gases of Volcanoes. By L. RICCIARDI (Gazzetta, 16, 38-42).-Gay-Lussac, Bunsen, and others, who have studied the gaseous emanations from craters and fumaroles, have concluded that at the commencement of the eruption, hydrogen chloride is evolved, which is succeeded immediately by sulphurous anhydride and other compounds. On the other hand, in the case of the eruption of Etna in the year 1883, the author found this order to be reversed, in that sulphurous anhydride was first evolved and subsequently hydrogen chloride; this point, however, is not insisted on.

As regards the origin of the hydrogen chloride, it probably arises from the decomposition of metallic chlorides, especially magnesium chloride, in the presence of steam at a high temperature. In confirmation of this view, it is shown that finely-powdered granite and lava, mixed with pure sodium chloride, evolves hydrogen chloride, the quantity of which is increased by blowing in a current of steam. On repeating the experiment, with the addition of a small quantity of potassium iodide, iodine is evolved, an element which has been found in the gaseous emanations from the crater of the island Vulcano in the Eolian group. Lastly, the formation of sulphurous anhydride is in all probability due to the interaction of calcium and magnesium sulphates, either singly or conjointly with the silica, whereby silicates are produced with separation of sulphuric oxide, which is decomposed into sulphurous oxide and oxygen. Thus (1) SiO, + MgSO = MgSiO, (enstatite) + SO,; (2) SiO, + CaSO, CaSiO, (wollastonite) + SO3; and (3) SiO2 + CaSO, + MgSO, MgCaSiO, (monticellite) + 2SO3. It was found that an artificial mixture of granite with magnesium or calcium sulphates evolved sulphurous anhydride.

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On the other hand, Bunsen attributes the formation of sulphurous anhydride to the oxidation of hydrogen sulphide, as also to the decomposition of sulphates of the alkalis and alkaline earths at high temperatures.

V. H. V.

Stromeyerite from Mexico. By G. A. KÖNIG (Zeit. Kryst. Min., 12, 621).—An analysis of stromeyerite from Zacatecas in Mexico gave the following results :

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This corresponds with the formula (AgCu),S. The mineral occurs in imperfect prismatic crystals in quartz. Its sp. gr. is 6.23.

B. H. B. Braunite from Jakobsberg in Wermland. By L. J. IGELSTRÖM (Zeit. Kryst. Min., 12, 659–660).—This mineral, discovered by the author some years ago, is found massive or in small crystals in

Archæan limestone. Analyses of the crystals gave the following mean results :

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Buratite from Laurium. By E. JANNETTAZ (Zeit. Kryst. Min., 12, 645).—The mineral forms small bundles of pale-green needles. The needles exhibit oblique extinction. Analysis gave the following results:

CO2. CuO. ZnO. H2O. Residue.
15.45 18.07 50.45 14.75 0.50

Total. 99.22

B. H. B.

Analyses of Bohemian Minerals. By B. ERBEN (Zeit. Kryst. Min., 12, 664-666).-The author gives analyses of the following minerals:-1. Carbonates from the felspar-basalt of Kolozruky between Laun and Brüx; 2. Fibrous barytes from Mies; 3. Comptonite from Katzenburg, near Leitzmeritz (formula RAL,Si2O + 2H2O); 4. Aluminium and ferric sulphates from Webrschan: (a.) white microcrystalline aggregate soluble in water, sp. gr. 1.72; formula (Al,Fe)2(SO4)3 + 15H2O, that is, the composition of keramobalite less 3H,O; (b.) compact yellow mass, becoming deep red on exposure to moist air, easily soluble in water; sp. gr. 2.038; formula (Fe,Al),(SO) + 12H2O, that is, the composition of Schrauf's ihleite. B. H. B.

Cyprusite. By J. DEBY (J. Roy. Mic. Soc., 4, 186-191; Zeit. Kryst. Min., 12, 616-618).-This mineral was first described by Reinsch (Abstr., 1882, 578). It forms thick veins in a melaphyr or dolerite containing zeolites. The principal locality where it is found is near Kynussa on the right bank of the Balahussa stream. The mineral is usually friable, but sometimes quite hard. Its sp. gr. is 1.8. It is insoluble in water, but soluble in acids, leaving an insoluble residue of 16.90 per cent. An analysis of the soluble portion gave the following results:

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from which the author deduces the formula Al,S3O12,8Fe2SO6 + 18H2O. The difference from the composition found by Reinsch is considerable. Under the microscope, the mineral is found to consist of hexagonal tablets, and an optical investigation showed that it belongs to the hexagonal system.

The author observed in several places the efflorescences mentioned by Reinsch. Their composition is as follows:

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Iron was found to be absent. The mineral was of a greenish-white

colour, and looked exactly like weathered ferrous sulphate. Its formula is 2Al2O3,5SO3 + 25H2O. B. H. B.

Hæmatostibiite, a New Mineral from Örebro. By L. J. IGELSTRÖM (Zeit. Kryst. Min., 12, 650-651).-At the Sjögrufvan iron mine, Örebro, Sweden, in fissures in compact tephroite in granulite interstratified in Archæan limestone, there occur barytes, a mineral resembling chondroarsenite, and the new mineral. The latter appears black, but is blood-red and transparent in thin sheets. It is rhombic, and exhibits distinct dichroïsm. Analysis gave the following results :

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In composition, the new mineral is very similar to manganostibiite (Abstr., 1886, 25). B. H. B.

Composition of Columbite from Graveggia in Val Vigezzo. By A. Cossa (Gazzetta, 17, 31-37).-Steuever has recently found columbite among the pegmatite minerals of Graveggia. It appears that columbite occurs in three typical forms, namely (i) black crystals of metallic lustre, sp. gr. 567, appearing brownish-red, when pulverised; (ii) more lustrous crystals than the preceding, sp. gr. 5-78; and (iii) crystals covered with a paste of a light green colour. An analysis of a specimen of the first type gave the following results:

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Nb2O5 and Ta2O. FeO. MnO. SnO2. CaO. MgO. Total. 9.84 8.98 0.23 1.17 trace 98.74

78.52

In the course of these analyses, it was observed that Marignac's method for the separation of niobic and tantalic acids, which is based on the difference in solubility of potassium flotantalate and oxyfluoniobate, although convenient for obtaining the acids in a state of purity, is not applicable to their quantitative separation. According to Marignac, potassium fluotantalate crystallises in the trimetric system, but the author shows by examination of the crystals by polarised light that they belong to the clinohedric form, a view confirmed by an examination of a large sample of the salt from the columbite of Connecticut. V. H. V.

Pectolite from Auchensterry Quarry, Kilsyth. By J. YOUNG (Zeit. Kryst. Min., 12, 620).—The specimens described are the finest examples ever seen from Western Scotland, where pectolite is of somewhat rare occurrence. The mineral occurs in the form of fine greyish-white needles, with harmotome and a black mineral, probably tourmaline, in thin veins in the dolerite at Kilsyth, north-west of Glasgow. Analysis gave

SiOg. 52.74

Al2O3. Fe2O3.
0.67 1.20

MgO. CaO.
1.52 31.86

Na,O. H2O.
9.60

2:00 B. H. B.

Manganese-zinc Serpentine from Franklin, New Jersey. By G. A. KÖNIG (Zeit. Kryst. Min., 12, 621-622).-The mineral examined was compact, dark brown in colour, translucent at the edges, and had a semi-conchoidal fracture; sp. gr. 2.635. The mean of two analyses gave the following results (I):—

SiO2. Fe2O3. MnO. ZnO. MgO. H2O. Total. I.... 42.20 2.80 7.44 3.90 29.24 14.04 99.62 II 6.91 3.10 29.24 14.04 94.99

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41.70 Analysis II gives the results obtained after subtracting 4:15 per cent. of franklinite. The author regards the mineral as a serpentine in which the magnesium is partially displaced by manganese and B. H. B. Biotite. By A. KNOP (Zeit. Kryst. Min., 12, 588–607).—The author gives the following analyses of biotite :

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I. Biotite from Böstenbach near Petersthal; II. Biotite from Freiersbach; III. Biotite from Easton, Pennsylvania; IV. Biotite from Oberbergen in the Kaiserstuhl; V. Biotite from the Klausenalpe: VI. Barium-biotite from the koppite-limestone of Schelingen in the Kaiserstuhl. These analyses exhibit great constancy in the percentages of alumina and alkalis; whilst the percentages of ferrous oxide and magnesia vary in such a way that their sums remain approximately equal. The mean of the six analyses gives the following oxygen ratio:

RO2 : R203 :

RO

as 2.1

: 1

:

1.4

This represents the formula R",RSO13. This formula might also be written RS3O, + RAL2O,; in which case biotite may be regarded as a molecular combination of amphiboloid material with spinell.

B. H. B. Pseudo-biotite. By A. KNOP (Zeit. Kryst. Min., 12, 607-609).A mineral resembling biotite, occurring in the granular limestone of

Schelingen in the Kaiserstuhl Mountains, was found on analysis to have the following composition:

SiO2. TiO2. Al2O3. Fe2O3. Mn2O3. MgO. KO. H2O. Total. 35.91 1.15 15.18 10.85 0.89 22.80 2.90 10.77 100.45 This altered biotite is termed by B. H. B.

Formula: R.Al, Si,O15 + 2H2O. the author pseudo-biotite.

Analysis of a Pink Clay. By A. DAMOUR (Zeit. Kryst. Min., 12, 655).—The argillaceous mineral described by Baret is soluble in dilute hydrochloric acid to the extent of 2.95 per cent. The residue is still of a pink colour. Analysis gave the following results:

SiO2.
Al2O3. FeO. MnO. MgO. K2O. H2O. Total.
53.11 21.22 1.04 0.40 2.32 0.79 21.70
Formula: AlSi,O2,12H2O. Sp. gr. 2.70.

100.58 B. H. B.

Meteoric Iron at Fort Duncan, Texas. By S. MEUNIER (Compt. rend., 104, 872-873).-This meteorite, which was discovered in 1882, is surrounded by a dull black crust, formed during its passage through the air. The interior has the colour of tin, with a characteristic silky lustre, and a crystalline fracture which shows cleavage. It contains elongated inclusions of the colour of silver, and darker masses with the colour of tombac. The meteorite has the composition Iron, 92.02; nickel (with traces of cobalt), 6·10; insoluble matter, 180 = 99·92; sp. gr. = 7.699. The insoluble matter consists of prismatic crystals of the variety of schreibersite known as rhabdite. The tombac-coloured inclusions are pyrrhotine, FS8, which is associated with daubréelite. In its composition, sp. gr., and the nature of the inclusions, this meteorite is almost identical with that which fell at Branau, July 14th, 1847. C. H. B.

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Examination of Schützenhof-Quelle, Wiesbaden. By H. FRESENIUS (J. pr. Chem. [2], 35, 237-254).-Yield about 160 litres a minute; temperature, 21st March, 1879, 49.2°; sp. gr. at 10°, 1.004999. The analysis gave in 1000 parts by weight: -NaCl, 5.154046; KCl, 0.157510; LiCl, 0.025228; NH,CI, 0.012340; CaCl,, 0585858; NaBr, 0002534; Nal, 0000028; CaSO, 0-134366, SrSO, 0020362; BaSO4, 0-000010; CaCO3, 0139495; MgCO3, 0124487; FeCO,, 0·002179; MnCO3, 0·000671; Ca,As2O, 0·000060; Al2P2O, 0.000334; aluminium silicate, 0.000401; SiO2, 0050907; total, 6-410816; combined carbonic anhydride, 0.127669; carbonic anhydride free, 0-308144; nitrogen, trace; also traces of rubidium, cæsium, nitric and boric acids, copper, hydrogen sulphide, and organic substances. Of the gases given off at the spring, 38-47 per cent. are absorbed by potash. The water contains no bacteria. water was led from the spring by enamelled iron pipes, but the water acted on them and the packing of the joints, with evolution of hydrocarbons and hydrogen sulphide, but since these pipes have been replaced by earthenware ones, no change is perceptible in the water as delivered at the baths, &c.

The

H. B.

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