Letter | Published:

On the Constitution of the Solid Crust of the Earth

Nature volume 5, pages 8182 | Download Citation


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ANOTHER contribution to a subject on which the author has laboured for many years—never perhaps very brilliantly, but always in the main soundly. Such unmitigated nonsense has been talked on the subject of the thickness of the solid crust of the earth, even by scientific men of real power—generally mere mathematicians, sometimes geologists, rarely indeed physicists—and such extravagant views on the subject are still propounded and defended by men like Delaunay, who have done good work in closely allied questions, that it is really refreshing to read Archdeacon Pratt's paper. Yet its tone is somewhat hesitating, almost apologetic, and he finally arrives at the conclusion that what seems to us to be at least a natural assumption to make at starting (viz., that a level surface may be drawn, not very many miles under the surface of the eaith, such that in spite of hills and ocean beds the amount of matter shall be the same in every vertical line between these two surfaces) leads to results not after all very inconsistent with those derived from actual pendulum observations made over the Indian Continent. Sir W. Thomson's bold investigation of the tides in the solid earth, due to elastic yielding, furnishes us with by far the most powerful mode of attacking the general question which has been devised since Hopkins's celebrated suggestion of the information to be derived from precession and nutation ; and it is to be hoped that the labours of the Tidal Committee of the British Association will soon furnish, from observation, the data required for its numerical application.

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  • 26 March 2018

    This article was initially published with an incorrect DOI. A new DOI has been assigned and registered at Crossref, and has been corrected in the article.

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