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Graustein.

NOME III. SIDERITE, WITH FELSPAR.

[FIRMICITE, from Julius Firmicus, who flourished under Constantine I. and first mentions alchemy, "scientiam alchemia*."]

The graustein of Werner is an intimate mixture of siderite with white felspar, which last often predominates. According to Mr. Jamesont it contains olivine and augite, like basaltin, and sometimes passes into that substance. It is frequent near Vesuvius, and in some other parts of Italy.

NOME IV. SIDERITE, WITH EARTHY
FELSPAR.

[SYNESITE, from Synesius, one of those Greek philosophers, in Egypt, who cultivated this science, A. D. 400.]

This combination has been described by Saus-
The mixture of siderite and felspar, in

sure.

* Matheseos iii. 15. Orosius first states, that Diocletian burnt the books of the Egyptians.

† iii. 190.

basalt and granitel, may be considered as a gradual approach to this intimate combination.

NOME V. FERRUGINOUS QUARTZ.

[ZOZIMITE, from Zozimus, one of the chief Greek philosophers of Egypt, who wrote on alchemy, A. D. 420.]

Near Sallenche, Saussure observed a rock, with protuberances, of a lively red, like cinnabar. When broken with a hammer it proved to be a micaceous ferruginous rock, with irregular nodules of quartz, tinged red with iron.

When the tender or micaceous part of this stone was exposed to the flame of the blow-pipe, it melted into a greenish and almost transparent glass; but the hard and quartzy parts scarcely suffered any change, except there were some free ferruginous particles, which in that case melted, and formed a black and brilliant dross, on the surface of the stone; but when the colouring part is intimately combined with this stone, it remains red and untouched*.

Sauss. 1134.

NOME VI. BASALTIN, WITH EARTHY
FELSPAR.

[GEBRITE, from Geber (Abou Moussa GIABER ben Haijam al Sofi), the first of the Arabian chemists, A. D. 830.]

Saussure afterwards describes another singular diamictonic rock, which he found near Mont Blanc.

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Fragments of a remarkable rock are afterwards observed; its colour is red, inclining to violet, like the dark lees of wine; it is not schistose, but in hard and compact masses; yields fire with steel In the fracture its grain appears a little scaly; and if observed with a lens, it is found mixed with dull grey parts. These parts, softer than the rest of the rock, become white when scraped with a knife, and are unquestionably of pierre de corne. As for the hard and reddish base, it seems to be of the same nature with that of several porphyries, which have been improperly classed among jaspers. The blast of the blow-pipe discolours and melts it, though with difficulty, into a transparent glass, strewed with small bubbles. This cha

racter belongs to felspar, and some kinds of petrosilex; but as this rock has not the fracture of petrosilex, I think I ought to look upon it as the earth of uncrystallised felspar. Fragments of this rock are found very plentifully spread on this road. I had not time to ascend to the rocks from which these fragments are detached, but I do not doubt, but that these rocks are situated like those of pierre de corne, which I have described in the preceding paragraph. Since I have become acquainted with this rock, I have found rolled pebbles of it in the environs of Geneva; so true is it, that we find in proportion to what we know."*

NOME VII. BASALTIN, WITH SIDERITÉ. [RHAZITE, from Rhazes, A. D. 900.]

This combination is far from uncommon, and may be found in most basaltic countries. It sometimes occurs even in schistose siderite. Basaltin, with siderite, from Saxony.

The same, from the Faroe Isles.

§ 1136.

NOME VIII. BASALTIN, WITH SILEX.

[EBENSINITE, from Eben Sina, or Avicenna, A. D. 1020.]

The siliceous part is generally felsite. Ba saltin sometimes passes into a more siliceous substance, which, in the north of Ireland, is schistose, and contains ammonites. It is supposed to be a detritus of the basaltin, mixed with siliceous particles in the primeval waters.

NOME IX. BASALTIN, WITH WACKEN.

(ALBERTITE, from Albertus Magnus, A. D. 1220.]

This combination sometimes occurs in Saxony, and other basaltic countries. But far more generally the basaltin is separated from the wacken by a positive line.

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