Nitrogen being acted on was manifestly diamagnetic in relation to common air when both were of the same temperature. Oxygen appears to be magnetic in common air. Hydrogen proved to be clearly and even strongly diamagnetic. Its diamagnetic state shows, in a striking point of view, that gases, like solids, have peculiar and distinctive degrees of diamagnetic force. Carbonic acid gas is diamagnetic in air. Carbonic oxide was carefully freed from carbonic acid before it was used, and it appears to be more diamagnetic than carbonic acid. Nitrous oxide was moderately, but clearly, diamagnetic in air. Olefiant gas was diamagnetic. The coal gas of London is very well diamagnetic, and gives exceedingly good and distinct results. Sulphurous acid gas is diamagnetic in air. Muriatic acid gas was decidedly diamagnetic in air.—On the Diamagnetic Conditions of Flame and Gases: Philosophical Magazine, 1847, p. 409.
[192] For illustration of this I must refer to my own Memoir, Researches on the Influence of Magnetism and Voltaic Electricity on Crystallization, and other conditions of matter, in the Memoirs of the Geological Survey of Great Britain, &c., vol. i.
[193] In a work published by Mr. Evan Hopkins, entitled On the Connexion of Geology with Terrestrial Magnetism, will be found many valuable practical observations made in this country and the gold and silver districts of America; but the views taken by the author are open to many objections.
[194] See a notice by Faraday of Morichini’s Experiments in Relations of Light to Magnetic Force—Philosophical Transactions, vol. cxxxvii. p. 15. See also Mr. Christie On Magnetic Influence in the Solar Rays—Philosophical Transactions, vol. cvii. p. 219; vol. cxix. p. 379.
[195] Sir David Brewster On Magnetism; republished from the Encyclopædia Britannica.
[196] The whole of the title of Kircher’s book will convey some idea of the subjects embraced:—Athanasii Kircheri Societatis Jesu Magnes, sive de Arte Magneticâ; opus tripartitum, quo Universa Magnetis Natura ejusque in omnibus Scientiis et Artibus usus novâ methodo explicatur: ac præterea e viribus et prodigiosis effectibus Magneticarum aliarumque abditarum Naturæ Motionum in Elementis, Lapidibus, Plantis, Animalibus elucescentium: multa hucusque incognita Naturæ Arcana, per Physica, Medica, Chymica, et Mathematica omnis generis Experimenta recluduntur Editio Tertia: ab ipso Authore recognita emendataque, ac multis novorum Experimentorum Problematibus aucta. Romæ, 1654.
[197] The following are the titles of the concluding chapters of Kircher’s book:—De magnetismo solis et lunæ in maria. De magneticâ vi plantarum. De insitionis magneticis miraculis. De magnetismo virgulæ auriferæ seu divinatoriæ. De plantis heliotropiis eorumque magnetismo. De magnetismo rerum medicinalium. De vi attractivâ potentiæ imaginativæ. De magnetismo musicæ. De magnetismo amoris.
[198] “For these reasons it appears most natural to seek their origin in the sun, the source of all living activity, and our conjecture gains probability from the preceding remarks on the daily oscillations of the needle. Upon this principle the sun may be conceived as possessing one or more magnetic axes, which, by distributing the force, occasion a magnetic difference in the earth, in the moon, and all those planets whose internal structure admits of such a difference. Yet, allowing all this, the main difficulty seems not to be overcome, but merely removed from the eyes to a greater distance; for the question may still be asked, with equal justice, whence did the sun acquire its magnetic force? And if from the sun we have recourse to a central sun, and from that again to a general magnetic direction throughout the universe, having the Milky Way for its equator, we but lengthen an unrestricted chain, every link of which hangs on the preceding link, no one of them on a point of support. All things considered, the following mode of representing the subject appears to me most plausible. If a single globe were left to move alone freely in the immensity of space, the opposite forces existing in its material structure would soon arrive at an equilibrium conformable to their nature, if they were not so at first, and all activity would soon come to an end. But if we imagine another globe to be introduced, a mutual relation will arise between the two; and one of its results will be a reciprocal tendency to unite, which is designated and sometimes thought to be explained by the merely descriptive word Attraction. Now would this tendency be the only consequence of this relation? Is it not more likely that the fundamental forces, being drawn from their state of indifference or rest, would exhibit their energy in all possible directions, giving rise to all kinds of contrary action? The electric force is excited, not by friction alone, but also by contact, and probably also, though in smaller degrees, by the mutual action of two bodies at a distance; for contact is nothing but the smallest possible distance, and that, moreover, only for a few small particles. Is it not conceivable that magnetic force may likewise originate in a similar manner? When the natural philosopher and the mathematician pay regard to no other effect of the reciprocal relation between two bodies at a distance, except the tendency to unite, they proceed logically, if their investigations require nothing more than a moving power; but should it be maintained that no other energy can be developed between two such bodies, the assertion will need proof and the proof will be hard to find.”—The above is a translation from Hansteen’s work On Magnetism.
[199] See article Animal Magnetism, Encyclopædia Britannica, and Mr. Braid’s papers On Hypnotism, published in the “Medical Times.”