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VII.—Preliminary Observations on Magnetic Induction in Ferric Oxide at Various Temperatures and in Different States, and on the Possible Chemical Changes indicated by the Observations

Published online by Cambridge University Press:  15 September 2014

G. E. Allan
Affiliation:
University of Glasgow
John Brown
Affiliation:
University of Glasgow
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Extract

In a previous paper by one of us, it was shown that a certain part of rock magnetism was variable and uncertain under the influence of raised temperature. In some instances the rock specimen became permanently more magnetic after it was heated in air, whereas, in the majority of cases, heating caused great loss of magnetic quality. It was suggested that the increase of magnetism observed was caused by the transformation of hæmatite into a more magnetic iron oxide.

In order to obtain material which might support this assumption, and also to amplify the work of previous investigators, experiments were undertaken with artificial and natural ferric oxide, in which the transformation of ferric oxide from a non-magnetic into a magnetic condition was observed, while some of the conditions which assist or impede this change were also studied.

Type
Proceedings
Copyright
Copyright © Royal Society of Edinburgh 1914

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References

page 69 note * Phil. Mag., April 1909.

page 69 note † Upsala Universitets Årsskrift, 1896; Mat. och Naturv., ii. 1, 1897.

page 69 note ‡ Neues Jahrb. f. Mineralogie, vol. i. pp. 62–88, 1907.

page 70 note * Wied. Ann., lxviii, pp. 658673, 1899Google Scholar.

page 70 note † Phil. Mag., Jan. 1904 and April 1909.

page 70 note ‡ ibid., April 1909, p. 574.

page 72 note * Archives des Sciences, xxxi. p. 89, Feb. 1911.

page 72 note † The air here referred to means the air of the furnace in which the bars were heated. Usually the electric furnace was stopped at one end with wool and obstructed at the other by the thermo-couple. The gas furnace was open to the air at both ends.

page 74 note * See Phil. Mag., Jan. 1904, curve 15.

page 81 note * see p. 77

page 83 note * Ann. Chim. et Phys., v. 21, pp. 199–255, 1880.

page 83 note † Ber. d. chem. Ges., xlii. 4, pp. 4575–4581, 1909.

page 83 note ‡ Siewert, , Jahresber. Chemie, pp. 265266, 1864Google Scholar; Glaser. Zs. anorg. Chemie, xxxvi. p. 21, 1903.

page 84 note ‡ Ann. Chim. et Phys., iii. 69, pp. 214–224, 1863.

page 84 note † Ber. d. chem. Ges., xl. 2, pp. 1958–1960, 1907.