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II.—Terrestrial Magnetism as Modified by the Structure of the Earth's Crust; and Proposals Concerning a Magnetic Survey of the Globe

Published online by Cambridge University Press:  01 May 2009

Extract

I Will now put forward some details, for it seems necessary that some proofs of what has been maintained in general should be given, and I shall therefore quote some examples of the intimate connexion between earth-structure and terrestrial magnetism. No diagrams could indicate the relations better than Locke's Magnetic Sections across the Hudson, which were taken at three different points of the Palisades, Snake Hill, Fort Lee and Patterson (see Plate XV.). The dip and intensity were in each case determined at a number of points along a line perpendicular to the range of cliffs, and the curves rise very suddenly to maxima just above the edges of the cliffs, which are composed of columnar diorite. This diorite is widely distributed and lies between masses of Triassic sandstone; the dip is slight and towards the west.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1889

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References

page 536 note 1 Nipher, F., Magnetic Survey of Missouri. Fifth Annual Report, Trans. St. Louis Ac., vol. iv. No 3, p. 516.Google Scholar Chart of the Magnetic Variation in Missouri, St. Louis, 1880. Sold at Robert Beneck's, St. Louis. Chart of the Magnetic Variation in Missouri (photograph of a plaster chart), St. Louis, 1881.

page 536 note 2 Rijckevorsel, Report to His Excellency the Minister of the Colonies on a Magnetic Survey of the Indian Archipelago, made in the years 1874–1877. Amsterdam, 1879.

page 536 note 3 Schenzel, Beiträge zur Kenntniss der magnetischen Verhältnisse im Sudostlichen Ungarn, Repert. f. Experimental Physik, f. physikal Technik, f. math. u. astron. Instrumentenkunde, Herausgeg. v. Carl, München, 1877, Bd. XIII. s. 165.

page 537 note 1 Notes on Secular Changes of Magnetic Declination in Japan, vol. v. of the Trans. Seism. Soc. of Japan.

page 538 note 1 The Physical Geography of Japan, Proc. R.G.S. Feb. 1887.

page 538 note 2 Cargill G. Knott, D.Sc. (Edin.), F.R.S.E., Professor and Aikitsu Tanakadate Professor of Physics, Imp. University of Japan, A Magnetic Survey of all Japan, carried out by Order of the President of the Imp. University, Journal of the College of Science, Imp. University Japan, vol. ii. part iii. Tokio, 1888.

page 539 note 1 There is something very striking in Dr. Knott's representation. The centre of the great loop of 4° 20´, which will be noticed in the main island, coincides with the intersection of the great longitudinal and transverse fissures (Fossa Magna) of Japan. His curve of equal total force, and that of equal horizontal force, also prove that the Fossa Magna has some influence on the magnetic curves.