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III.—On the Substitution of Zinc For Magnesium in Minerals

Published online by Cambridge University Press:  01 May 2009

Edward T. Hardman
Affiliation:
Of the Geol. Survey of Ireland, Associate of the Royal College of Science, Dublin.

Extract

In the Geological Magazine of last October I have noticed the occurrence of zinc in small quantities in the White Limestone (Chalk) of the Co. Tyrone, and also in the overlying basalt. When that paper was read, exception was taken to the latter part of it, on the ground that-the metal in question had never been known to exist in rocks of igneous origin; but as my analysis seemed perfectly trustworthy, I saw no reason to modify it on the objections then put forward. Since then, whilst making an investigation.– with a different object–on a specimen of basalt from another locality in the neighbourhood of that whence the one originally examined was obtained, I succeeded in again finding zinc in it; and I think it well to mention the fact now, as an addendum to, and as confirming my former statement.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1874

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References

page 201 note 2 Vol X. page 434.

page 201 note 3 Before the Royal Geological Society of Ireland, June 11, 1873.

page 202 note 1 Fownes' Manual of Chemistry, 10th ed. p. 393; also Galloway's Qualitative Analysis, p. 49.Google Scholar

page 202 note 2 Supra cit.; also Dana's Manual of Mineralogy, p. 74.Google Scholar

page 202 note 3 Although in one or two cases implied.

page 203 note 1 Leinster Granite.

page 203 note 2 The zinc most probably occurs here in the dark magnesian mica.

page 203 note 3 It is therefore not entirely metamorphosed.

page 203 note 4 The specimens from the Survey Collection were obtained by the kind permission of Prof. Hull, F.E.S., Director of the Geological Surrey of Ireland.

page 204 note 1 This was rendered possible by the use of paraffin oil in the blowpipe lamp, by which a very large and hot flame was procured, capable of decomposing a much larger quantity of rock. For reductions, and where great beat is required in blowpipe analysis, it will be found most useful where gas is unattainable.