Page:Memoirs of the Geological Survey of Great Britain, Volume 1.djvu/446

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Researches on the Influence of Magnetism and Voltaic Electricity, on Crystallization, and other Conditions of Matter. By Robert Hunt, Keeper of Mining Records.

A.—INFLUENCE OF MAGNETISM.

1. An attentive examination of the peculiar characteristics of the rocks which form the crust of the earth, leads to the conclusion, that they have, during the process of consolidation, been subjected to the influences of forces which appear to act independently of the powers of cohesion.

Although the consolidation of rocks is often due to the force of aggregative attraction, sometimes assisted by the agglutinizing properties of silica, or other cementing principles, it is evident that their molecular arrangement is frequently produced by some other power; and that crystalline structure is in all cases dependent upon some disposing agent, acting often in opposition to the influence of simple cohesion.

2. Geologists have observed a remarkable uniformity in the laminations of strata, and the divisional planes of rocks have been found by them to observe some approach to a distinct order of arrangement; in many cases approximating to the direction of the present magnetic meridian.[1]

Such arrangements we cannot but suppose to be dependent upon some influence, universal in character and constant in action, which is exerted in giving to the particles of matter certain conditions or properties, upon which depend their order of position in the mass; in other words, these particles are impressed with the power of arranging themselves according to some law of polarity, which may, or may not, be due to electrical excitation. The singular powers exerted by electrical currents upon matter; breaking up the strong forces of chemical affinity; re-arranging the atomic elements, and giving new forms to compound bodies, naturally lead to the supposition, that this power, which is manifestly diffused through all matter, may be concerned in producing the

  1. "Although the direction of the present magnetic meridian in the district may be merely temporary, and the approximation of so many great divisional planes to it therefore accidental, still their great prevalence, both in the igneous rocks and sedimentary deposits, in that direction, leads us to suppose that polar forces may have considerably governed the arrangement of the component matter of the rocks they traverse, during consolidation, either from the cooling of the former, or the chemical changes which have taken place in the latter."—Geological Report on Cornwall, Devon, &c., Sir Henry De la Beche.