The eleventh chapter of Wilkinson’s work contains the analysis of the report drawn up by Mr. J. N. Hallé in behalf of the commission appointed by the French National Institute. This commission, which was organized to look into (examiner et vérifier) the different galvanic experiments which had been made and to ascertain their effects and results, was composed of such distinguished French physiologists as Coulomb, Fourcroy, Vauquelin, Charles, Sabathier, Hallé, Pelletan and Guyton de Morveau, who were afterward joined by both Humboldt and the celebrated Prof. Venturi, of Modena.
Humboldt’s observations respecting the application of galvanism to medicine are embodied in his well-known letter to M. Loder, inserted in “La Bibliothèque Germanique,” Vol. IV, Messidor, An. VIII. p. 301, and are likewise detailed by Wilkinson (Chap. XIII) where references are made, more particularly, to the experiments of Hufeland, Behrends, Creve, Hymly, Pfaff and Anschell.
Between the years 1799 and 1804 Von Humboldt made observations upon the magnetic intensity of the earth, of which an account will be found in Vol. XV of the Annalen der Physik. These were made upon the American Continent during the course of his well-known journey, the equal of which latter, says Petersen, has not been seen since the days when Alexander the Great fitted out an extensive scientific expedition for Aristotle.
Humboldt’s observations in the same line were continued for many years, notably between 1805 and 1806, in company with Gay-Lussac during a tour which they made together through France, Switzerland, Italy and Germany, as related in the first volume of the Mémoires de la Société d’Arcueil.
Some idea can be formed of the extent of Humboldt’s share in the magnetical labours of the first half of the century by perusing the last chapters of his “Cosmos” and the third volume of his “Relation Historique.” At p. 615 of the last-named work, he himself says: “The observations on the variation of terrestrial magnetism, to which I have devoted myself for thirty-two years, by means of instruments which admit of comparison with one another, in America, Europe and Asia, embrace an area extending over 188 degrees of longitude from the frontier of Chinese Dzoungarie to the West of the South Sea, bathing the coasts of Mexico and Peru, and reaching from 60 degrees North latitude to 12 degrees South latitude. I regard the discovery of the law of the decrement of magnetic force from the pole to the equator as the most important result of my American voyage.”
Humboldt was the first who made especial observations of those irregular perturbations to which he applied the name of “magnetic-storms,” and the effects of which he originally observed at Berlin in 1806. These are treated of in his “Cosmos,” London, 1858, Vol. V. pp. 135, etc., wherein he states that, when the ordinary horary movement of the needle is interrupted by a magnetic-storm, the perturbation manifests itself often simultaneously, in the strictest sense of the word, over land and sea, covering hundreds and thousands of miles, or propagates itself gradually, in short intervals of time, in every direction over the earth’s surface. In this same work (“Cosmos,” Sabine’s translation, Vol. I. p. 180), he contributes a graphic description of the concurrent and successive phases of a complete aurora borealis, reference to which is made by Noad (“Manual,” etc., pp. 228, 229, 235), who, likewise, gives (pp. 612–615) an account of the establishment of magnetic stations at different points, for simultaneous observations, upon a plan originally laid out by Humboldt.
As early as 1806, this great naturalist had published at Erfurt his “Inquiry Concerning Electrical Fishes.” While at Naples with Gay-Lussac, during the previous year, they had examined the properties of the torpedo, and had observed more particularly that the animal must be irritated previous to the shock, preceding which latter a convulsive movement of the pectoral fins is noticeable, and that electrical action is prevented by the least injury done to the brain of the fish; also, that a person accustomed to electrical discharges could with difficulty support the shock of a vigorous torpedo only fourteen inches long; that the discharge can be felt with a single finger placed upon the electrical organs, and that an insulated person will not receive the shock if the fish is touched with a key or other conducting body (Phil. Mag., Vol. XXII. p. 356; Annales de Chimie, No. 166; “Encycl. Brit.,” 1855, Vol. VIII. p. 573). Humboldt’s account of the mode of capturing gymnoti is detailed at pp. 575, 576 of the last-named work, as well as at pp. 472–474 of Noad’s “Manual of Electricity,” London, 1859.
At request of the King of Prussia, Humboldt returned from Paris to his native city in 1827, and it was during the winter of 1827–1828 that he began in Berlin his lectures on “Cosmos, or Physical Universe.” This is the title of his chief work, which has universally been recognized one of the greatest productions ever published, and one which Ritter pronounced as being the culminating point both in the history of science and in the annals of civilization.
References.—Klenke, “Alex. Von Humboldt, ein biographisches Denkmal,” 1851: “Alex. Von Humboldt ... von Wittwer,” Leipzig, 1861; “Life of Alex. Von Humboldt,” translated by J. and C. Lassell, 2 Vols., London, 1873; “Meyer’s Konversations-Lexikon,” Leipzig und Wien, 1895, Vol. IX. pp. 44–47; Delambre’s eulogium on Humboldt will be found at p. 15, Vol. XV of “Edinburgh Review”; Gren’s “Neues Journal der Physik,” Vol. IV; Annales de Chimie, Vol. XXII; An. Chim. et Physique, Vol. XI; Poggendorff’s “Annalen,” Vols. XV, XXXVII; “Société Philomathique,” Tome I. p. 92; “Opus. Scelti,” XXI. p. 126; Knight’s “Mech. Dict.,” Vol. II. p. 1874; Phil. Mag., Vol. VI (1800), pp. 246, 250; “Cat. of Sc. Papers of Roy. Soc.,” Vol. III. pp. 462–467; Vol. VI. p. 692; Vol. VII. pp. 1035–1036; Sc. Am. Supp., No. 457, pp. 7301, 7302; Noad, “Manual,” pp. 425, 528, 529, 612; Harris, “Rudim. Magn.,” Part III. p. 103; Walker, “Ter. and Cos. Magn.,” 1866, p. 81; Humboldt, “Aphorismi ex doctrina ...” 1793; “Voyage, etc., dans les années, 1799–1804”; “Report of Seventh Meeting of British Association,” Vol. VI, London, 1838, pp. 1, 5 and 7, and the remainder of Major Sabine’s able article upon “Magnetic Intensity,” in the same volume; “Report of the Meeting of the French Academy of Sciences” of May 21, 1849, for extract of a letter from Emile H. Du Bois-Reymond, sent by Humboldt, and treating of the Electricity of the Human Frame (“L’Institut,” Mai 23, 1849); S. H. Christie and Sir G. B. Airy, “Report upon a Letter ...” London, 1836; C. H. Pfaff, “Mém. sur les expér. de Humboldt ...” 1799; Houzeau et Lancaster, “Bibl. Gén.,” Vol. II. pp. 168, 1580–1581.
A.D. 1800.—William Nicholson, editor of the journal bearing his name, as well as an able chemist, and Sir Anthony (then Mr.) Carlisle, an English surgeon, while carrying on a series of chemical experiments, discover that, by means of the voltaic pile, water is decomposed into its constituents of oxygen and hydrogen. Their pile consisted of seventeen silver half-crown pieces alternated with equal discs of copper and cloth soaked in a weak solution of ordinary salt, and, having used a little water to make good the contact of the conducting wire with a plate to which the electricity was to be transmitted, Carlisle observed that gas was being set free in the water, while Nicholson recognized the odour of hydrogen proceeding from it. The better to observe this result they afterward (May 2, 1800) employed a small glass tube, which, after being filled with water, was stopped at both ends with corks through which passed two brass wires extending a little distance into the water. When platinum wires were used, gas bubbles appeared from both wires, and the two gases, hydrogen from the negative and oxygen from the positive end, were found to be nearly in the proportion to constitute water. (See account of above in Pepper’s “Electricity,” p. 312, as well as at pp. 193 and 194 of Fahie’s “History of Telegraphy to 1837,” and at pp. 339 and 340 of Vol. I of Lardner’s “Lectures.”)