[142] Faraday’s Experimental Researches on Electricity. This philosopher has shown, by the most conclusive experiments, “that the electricity which decomposes, and that which is evolved by the decomposition of, a certain quantity of matter, are alike. What an enormous quantity of electricity, therefore, is required for the decomposition of a single grain of water! We have already seen that it must be in quantity sufficient to sustain a platinum wire 1/104 of an inch in thickness, red hot, in contact with the air, for three minutes and three quarters. It would appear that 800,000 charges of a Leyden battery, charged by thirty turns of a very large and powerful plate machine, in full action—a quantity sufficient, if passed at once through the head of a rat or cat, to have killed it as by a flash of lightning—are necessary to supply electricity sufficient to decompose a single grain of water; or, if I am right, to equal the quantity of electricity which is naturally associated with the elements of that grain of water, endowing them with their mutual chemical affinity.”
[143] Experimental Researches: Faraday.
[144] The appearance of acid and alkaline matter, in water acted on by a current of electricity, at the opposite electrified metallic surfaces, was observed in the first chemical experiments made with the column of Volta—(see Nicholson’s Journal, vol. iv. p. 183, and vol. iv. p. 261, for Mr. Cruickshank’s Experiments; and Annales de Chimie, tom. xxxvii. p. 233, for those of M. Desormes): On some Chemical Agencies in Electricity: by Sir Humphry Davy.—Philosophical Transactions for 1807. The various theories of electro-chemical decomposition are carefully stated by Faraday, in his fifth series of Experimental Researches on Electricity, in which he thus states his own views:—“It appears to me that the effect is produced by an internal corpuscular action exerted according to the direction of the electric current, and that it is due to a force either superadded to or giving direction to the ordinary chemical affinity of the bodies present. The body under decomposition may be considered as a mass of acting particles, all those which are included in the course of the electric current contributing to the final effect; and it is because the ordinary chemical affinity is relieved, weakened, or partly neutralized by the influence of the electric current in one direction parallel to the course of the latter, and strengthened or added to in the opposite direction, that the combining particles have a tendency to pass in opposite courses.”
[145] “This capital discovery (chemical decomposition of electricity) appears to have been made in the first instance by Messrs. Nicholson and Carlisle, who observed the decomposition of water so produced. It was speedily followed up by the still more important one of Berzelius and Hisinger, who ascertained it as a general law, that, in all the decompositions so effected, the acids and oxygen become transferred and accumulated around the positive, and hydrogen, metals, and alkalies around the negative, pole of a voltaic circuit; being transferred in an invisible, and, as it were, a latent or torpid state, by the action of the electric current, through considerable spaces, and even through large quantities of water or other liquids, again to reappear with all their properties at their appropriate resting-places.”—Discourse on the Study of Natural Philosophy: by Sir John Herschel, Bart., F.R.S.
[146] Numerous beautiful illustrations of this fact will be found in Becquerel’s Traité Expérimental de l’Électricité et du Magnétisme.
[147] See Le Feu élémentaire of l’Abbé Nollet; Leçons de Physique, tom. vi. p. 252; Du Pouvoir thermo-électrique, by M. Becquerel—Annales de Chimie, vol. xli. p. 353; also a Memoir by Nobili, Bibliothèque Universelle, vol. xxxvii. p. 15; Experimental Contributions towards the theory of Thermo-Electricity by Mr. J. Prideaux—Philosophical Magazine, vol. iii., Third Series; On the Thermo-Magnetism of Homogeneous Bodies, with illustrative experiments, by Mr. William Sturgeon—Philosophical Magazine, vol. x. p. 1–116, New Series. Botto made magnets and obtained chemical decomposition. Antinori produced the spark. Mr. Watkins heated a wire in Harris’s Thermo-Electrometer.
[148] A very ingenious application of the knowledge of this fact was suggested by Mr. Solly, by which the heat of a furnace could be constantly registered at a very considerable distance from it. See Description of an Electric Thermometer: by E. Solly, Jun., Esq. Philosophical Magazine, vol. xx. p. 391. New Series.
[149] Humboldt; Personal Narrative, Chap. xvii.—Annales de Chimie, vol. xiv. p. 15.
[150] Experimental Researches on Electricity. Series xv. Consult Sir Humphry Davy: An Account of some Experiments on the Torpedo.—Philosophical Transactions, 1829, p. 15. John Davy, M.D., F.R.S.: An Account of some Experiments and Observations on the Torpedo, ibid., 1832, p. 259; and the same author’s Observations on the Torpedo, with an Account of some Additional Experiments on its Electricity; and Matteucci, Bibliothèque Universelle, 1837, vol. xii. p. 174.
[151] On Lightning Conductors, by Sir William Snow Harris; Observations on the Action of Lightning Conductors, by W. Snow Harris, Esq., F.R.S.—London Electrical Society’s Transactions. Numerous valuable papers On Electricity, by Sir William Harris, will be found in the Philosophical Transactions.