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IV. A Chemical Analysis of Three Species of Whinstone, and Two of Lava
Published online by Cambridge University Press: 17 January 2013
Extract
On the 5th of August last, I announced to the Society that I had discovered soda in several varieties of the whinstone of Scotland, and also in lava from Mount Ætna, but did not describe the various experiments to which these substances had been subjected in my examination of them. In the following paper, therefore, I have the honour of laying an account of these experiments before the Society.
- Type
- Research Article
- Information
- Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 5 , Issue 1 , 1805 , pp. 76 - 98
- Copyright
- Copyright © Royal Society of Edinburgh 1805
References
page 76 note * The name whinstone is used throughout this paper in a generic sense, comprehending basalt, trap, certain kinds of porphyry, wacken, and some other stones of the argillaceous class.
page 78 note * The fusibility of this, and the other substances to be afterwards mentioned, I examined with Sir James Hall. For this purpose, a small piece of each was placed, with a pyrometer as near to it as possible, in an open muffle previously heated to redness. It could thus be seen perfectly during the operation, and the fire being raised, as soon as it was found to be soft, when pressed slightly by an iron rod, the degree of heat was ascertained by measuring the pyrometer.
page 78 note † The mortar I used was not scratched by any of the whins or lavas mentioned in this paper.
page 81 note * It therefore contained none of the earth which Vauquelin lately discovered, and to which he has given the name of glucine.
page 81 note † I Think, however, it is probable, that this basalt contained a small quantity of manganese, both from the brownish colour of the solution, No. 1. and from the green colour which the undissolved residuum gave, by fusion, with caustic potash.
page 85 note * This species is the first mentioned in Sir James Hall's paper. When powdered, it effervesced slightly with acids. I did not analyze it; but, in the course of the process for detecting soda, one of the earthy precipates proved, upon examination, to be magnesia. It is the only whin in which I have found this earth.
page 87 note * This is nearly the proportion given by Mr Kirwan.
page 88 note * In the 26th volume of the Annales de Chimie, p. 119. M. Scherer, in a letter to van Mons, Says, that he was informed by Dr Black, that Dr Hutton had, long ago, found potash in zeolite. In this statement M. Scherer is incorrect; because it was soda, as above mentioned, which Dr Hutton obtained from that substance.
page 93 note * Dolomieu, in describing this lava, says, that its fracture is conchoidal, like that of silex. The Specimen which I analyzed had an uneven fracture; and its colour was blackish-blue: in other respects, however, it answered to Dolomieu's description.
page 96 note * Since these experiments were performed, I have seen several decomposed sandstones, on the surfaces of which there was an efflorescence of common salt.
page 97 note * Mr Klafroth uses lime made of Carrara marble, which he boils with the alkali. (Beiträge, vol. i. preface).
page 97 note † Mr Lowitz, in describing his process for crystallizing caustic potash, directs the last evaporation to be performed in a glass resort. This method is very erroneous; as the alkali, when heated and concentrated, will dissolve large quantities of the glass.