XI.

Analysis of the Bronzite. By Mr. KLAPROTH*.

A VERY remarkable fossil, found in large masses in the Bronzite.

strata of serpentine near Kranbat in Upper Stiria, has been known within these few years by the name of bronzite. The following are its characters, as given by Mr. G. R. Karsten.

Its colour is a light tombac brown.

It is in masses, disseminated in large pieces.

It has a metallic semibrilliancy.

Its fracture is lamellar, very distinct from simple splitting.
The pieces separated are large grained.

In thin plates, it is translucid: in the mass, opaque.
Where scraped it appears white.

It is semihard, and very brittle.

Its specific gravity is not great. That of the specimen analysed was 3.2.

Its characters.

A. Exposed to a red heat for half an hour its colour Analysed. was rendered a little lighter, and it lost half a part per

cent.

B. a. 100 grains of bronzite were thickened with a lixivium containing 200 grains of potash, and then kept at a red heat for half an hour. The mass, which had not entered into fusion, was triturated in a mortar, then softened with hot water, supersaturated with muriatic acid, and completely dissolved. Being evaporated to dryness, and then treated with water acidulated with muriatic acid, the silex Silex. remained, which, after calcination, weighed 60 grains.

b. The muriatic solution was neutralized cold with carbonate of soda. The precipitate, treated with a boiling lixivium of potash imparted nothing to it. Well washed and heated red hot, 10-5 grs. of oxide of iron remained.

c. The colourless liquid, thus divested of iron, was made to boil, after which a sufficient quantity of carbonate of soda was added to decompose it entirely. The preci

Annales de Chim. vol, LXV, p. 107. Translated from Gehlen's Journal.

Oxide of iron.

Magnesia.

Component parts.

pitate obtained, after being strongly heated, consisted of 27.5 grains of pure magnesia.

C. Sixty grains of bronzite were heated red hot with 300 grains of nitrate of barytes, till the nitrate was completely decomposed. The mass, being triturated, diluted with water, and supersaturated with sulphuric acid, was boiled for some time, and then filtered. The free sulphuric acid having been saturated in great part with ammonia, acetate of barytes was added. The supernatant liquid was poured off, and evaporated to dryness. The residuum was heated red hot, then clutriated with hot water, and the liquid filtered off. This liquid contained a trace of potash, for reddened litmus paper acquired a blue tinge from it after some time; but one drop of nitric acid was more than sufficient to destroy this alkalinity, and give the liquid an acid character.

Bronzite therefore is composed of

Occurs disseminated in serpentine.

Hany's dial

lage,

The bronzite here described is the only instance known of its being found in compact masses; though it is frequently found in little separate pieces in serpentine; for instance, near Teinach, in the Pacher-Alp, in Lower Stiria, at Mount Hradicko in Moravia, at Zellerwalde near Siebenlehn, near Guanabacoa in Cuba, &c.

It is not yet decided whether the schillerstein (schillerspath, schillerblende) in the serpentine of Baste, near Hartzbourg, in the Hartz, may also be classed with it. As the analyses of this mineral yield alumine to the amount of 0.23 according to Heyer, and of 0.18 according to Gmelin, it should be classed with the schillernden hornblende, as has already been done by Mr. Karsten, if this large proportion of alumine be confirmed.

Mr. Hauy has made a separate species under the name of diallage, in which he has classed the smaragdite as green lamello-fibrous diallage, and the bronzite he gives as a variety

of

of this by the name of bronzed metalloid lamello-fibrous diallage. On the contrary he separates from it the Labrador hornblende, of which he makes a distinct species under the name of metalloid, reddish brown, laminar hyperstène.

the bronzite.

In my opinion our bronzite cannot be ranked with the different from emerald, or the diallage, as it is of a different nature; for, according to the analysis of Mr. Vauquelin, the diallage not only contains a little magnesia and alumine, but a preponderant proportion of lime, to say nothing of the chrome. It is distinguished too by melting alone into a scoria before the blowpipe, while the bronzite is infusible.

XIL

Extract from a Letter of Mr. GEHLEN, on the Analysis of the Kannelstein and Greenland Garnet, on some Metallic Succinates, &c.*

some fossils,

IN my way through Berlin Mr. Klaproth gave me the ana- Analysis of lyses of the kannelstein, Greenland garnet (almandine), and haarkies (capillary pyrites, Brochant, II, 127). The first, you know, has been classed in the zirconian genus; and Mr. Lampadius, of Freyberg, imagined he found in it zircon and potash. Mr. Gruner, of Hanover, and Mr. Trommsdorf, of Erfurt, who have analysed the Greenland garnet, assert, that they found zircon in this also. Neither of these fossils however afforded Mr. Klaproth any of this earth, the following being the results of his analyses.

Capillary pyrites native nickel. Succinic acid separates iron from manga

nese.

oxide of manganese 0.50

98.75

The capillary pyrites is not a sulphuret of iron, but native nickel, with a little cobalt and arsenic.

Several years ago, you know, in my examination of amber, and its acid, which I have not yet published, I found, that the succinate of iron was insoluble in water; that of manganese, on the contrary, very soluble; and that on this I founded an easy method of separating these two metals, which has since been much employed by Klaproth, Vauquelin, and others. The basis of this process being the different, or I may say, inverse solubility of two saline combinations, it was obvious, that other acids might produce a similar result. Accordingly Mr. Berzelius mentioned the supposed to do benzoic acid, which however I cannot think very suitable, as Mr. Trommsdorff asserts, that the benzoate of iron is very soluble. Mr. John has lately employed with the same view the oxalic acid, and acidulous oxalate of potash; and Mr. Simon, an eminent chemist of Berlin, confirms their utility in a paper he has just written on the analysis of some fossils, the colophonite, scapolite, &c.; and he observes they are preferable to the succinic acid, because the oxalate of iron is less bulky than the succinate.

Benzoic acid

the same.

Oxalic acid preferable.

Titanium precipitated by

tannin, not by gallic acid.

The same chemist has examined the phenomena exhibited by the gallic acid and tannin with titanium. This metal is not precipitated from its solutions except by tannin, or substances containing it.

INDEX.