Part 2 / Book 6 — Book VI (continued 8)

Sect. V relates to the classification of active substances into exciters and conductors of the galvanic fluid.

Sect. VI treats of experiments on the comparative effects of animal and vegetable substances employed in the galvanic chain.

Sect. VII describes, in a tabular form, the conducting substances, and those by which the galvanic fluid is insulated. In the employment of very long conductors, it was not possible for Humboldt to remark any interval between the instant when the muscle contracts and the moment the contact of the conductor takes place, the muscle and nerve being from two hundred to three hundred feet distant from each other. This announces a celerity of twelve hundred feet per second. The effect would be the same, should the conductors even be from ten thousand to twenty thousand feet in length. Thus Haller, in his physiology, ascribes to the nervous fluid a swiftness sufficient to enable it to run over a space of nine thousand feet a second. The calculation of Sauvages is carried to thirty-two thousand four hundred feet in the same space of time; and what is still infinitely more surprising, its celerity is estimated by the author of the essays on the mechanism of the muscles at five hundred and seventy-six millions of feet (upward of one hundred thousand miles) in the above space of a second of time. It ought here to be noticed that the great differences in these calculations arise from the different kinds of experiments on which they are founded.

Sect. VIII proves that the nerve which is intended to excite contractions in a muscle should be organically united with it, and it deals with the effects of galvanism upon vegetables, aquatic worms, insects and fishes.

Sect. IX describes the effects of galvanism upon amphibious animals, referring to the observations of Nollet, Rosel, Haller, Spallanzani, P. Michaelis and Herembstads.

Sect. X treats of the all-important effects of galvanism upon man, and makes allusion to the experiments of Hunter, Pfaff, Fowler, Munro, Robison, Hecker, Carradori, Achard, Grapengieser, Schmuck, Ludwig, Creve, Webster and Volta. In speaking of the observations made by the last named upon the tongue, he observes that some idea of them had been given thirty years before, in Sulzer’s work entitled “The New Theory of Pleasures,” published in 1767; and that if, at the above period, the consideration of the superficial situation of the nerves of the tongue had led to the artificial discovery of a nerve, the important discovery of metallic irritation would have been made in the time of Haller, Franklin, Trembley, Camper, and Buffon. How great a progress would not this revelation have made if the above philosophers had transmitted to us, thirty years ago, the theory and experiments which we leave to our successors?

Volta having singled out the differences, in point of savour, which result from galvanic experiments on the tongue according to the nature and disposition of the coatings, Humboldt repeated these experiments and added to them several of his own, with a nearly similar result. His different trials, however, having failed to produce any contraction of the tongue, appear to have established the truth of the ancient assertion of Galen, confirmed by Scarpa, namely, that the nerve with which the tongue is supplied by the third branch of the fifth pair is exclusively devoted to the sense of tasting, and that the ninth pair are exclusively destined for the motion of the tongue. This has been evidently proved by the galvanic experiments on the nerve in question.

The termination, in the pituitous membrane, of the nerves belonging to the organ of smelling, which originate in the first pair and in the first two branches of the fifth, together with the observation of the innumerable phenomena of sympathy between the organs of sight and those of smell and taste, had led to a presumption that, by galvanizing the nostrils, the smell would be affected. This supposition has not, however, been confirmed by any experiment.

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.”)

During the year 1781 William Nicholson had published the first edition of “An Introduction to Natural Philosophy.” In the second section of the third book of the latter work he treats of magnetism, the methods of communicating it, and the variation of the compass. The loadstone, he says, “is a ponderous ore of iron, usually of a dirty black colour and hard enough to emit sparks with steel. It is found in most parts of the world, and possesses a natural magnetism acquired most probably from its situation or position with respect to the earth.” In the third section of the same third book he discourses upon electrical matter, electrical jars, electrical instruments, and devotes much space to the explanation of experiments and facts touching natural and atmospheric electricity, balls of fire, of the ignis fatuus, or will-with-the-wisp, of waterspouts, earthquakes, etc., alluding to most of the then well-known observations thereon recorded by different scientists.

To Nicholson is due the invention of a revolving doubler, an improvement upon that of Abraham Bennet, which is described and illustrated in the “Encyclopædia Britannica,” as well as in No. 647, p. 10327, of the Sci. Am. Supplement (Read at A.D. 1794, also Phil. Trans., Vol. LXXVIII. p. 1, for M. Cavallo’s remarks upon the defects in Bennet’s doubler).

The above-named discovery of Nicholson and Carlisle, which, Mr. Davy says (Phil. Trans. for 1826, p. 386) was the true origin of all that had been previously done in electro-chemical science, together with Hisinger and Berzelius’ decomposition of salts, and the successful decomposition of ammonia, nitric acid, etc., made by the distinguished English chemical philosopher, Dr. William Henry (Nicholson’s Journal, Vol. IV. pp. 30, 209, 223 and 245; “Encyclopædia Metropolitana,” Vol. IV. pp. 221 and 611; Hutton’s abridgment of Phil. Trans., Vol. X. pp. 505, 599), as well as Davy’s decomposition of the earths and alkalies, creates at the commencement of another century, as we have already observed, an entirely new epoch in the history of chemistry.

References.—Nicholson’s letter to the Royal Society, read June 5, 1788, entitled “A description of an instrument which, by the turning of a winch, produces the two states of electricity without friction or communication with the earth” (influence or induction machine!); Nicholson’s Journal, 1800, Vol. IV. p. 179; Despretz, “Physique,” 1827, p. 432; Mechanics’ Magazine, Nov. 9, 1839; biography in “English Cyclopedia,” Vol. II. p. 82; Tomlinson, “Cyclopedia of Arts,” etc., 1862, Vol. I. p. 566; “Memoir of Joseph Henry,” 1880, p. 78; Highton, “The Electric Telegraph,” p. 28; Noad, “Manual,” p. 353; “Encycl. Brit.,” 1855, Vol. XXI. p. 628; Phil. Trans., Vol. LXXIX. p. 265; Philosophical Magazine, Vol. VII. p. 337, and XLV. p. 396; C. H. Wilkinson, “Elements of Galvanism,” 1804, Vol. II. pp. 21, 22, 46, 68, 375, etc.; “Bibl. Brit.,” Vol. XIX. p. 274; “Sciences et Arts,” Part I. p. 274, and Part II. p. 339, for Volta’s answer to Nicholson. For various treatises on, and methods of, effecting the decomposition of water, consult Adam W. Von Hauch (Mons’ Jour. de Chimie, Vol. I. p. 109); G. Carradori (Journal de Physique, An. XII. p. 20, “Nuova Scel. d’Op.,” quarto, Vol. I. p. 29, Paris and Milan, 1804); W. Wilson (Phil. Mag., Vol. XXII. p. 260); Cioni e Petrini (Brugnatelli’s An. di Chim., Vol. II. p. 322, 1805); M. Van Marum’s letter to Nauche (Jour. du Galvan., Eleventh Book, p. 187; Gilb. Ann., XI. p. 220); J. C. I. A. Creve, as at Ronalds’ “Catalogue,” p. 119; “Bibl. Britan.,” An. VIII. vol. xv. p. 23 and An. IX. vol. xvi. p. 23; J. C. Cuthbertson (Phil. Mag., Vol. XXIV. p. 170, 1806); Jos. Mollet’s Memoirs published at Aix and Lyons, 1821, 1823, as well as in the Reports of the Lyons Academy, 1823, 1825, and in the Comptes Rendus for 1823; Mr. Leeson (Sturgeon’s Annals, Vol. IV. p. 238, 1839; Robert Hare, Trans. Am. Phil. Soc., N.S., Vol. VI. p. 339; L. Palmieri and P. Linari-Santi, “Telluro-Elettricismo,” 1844; M. Merget’s theses, read before the Paris Academy, Aug. 30, 1849; A. Connel, Phil. Mag., 4th Ser., for June 1854, p. 426); Dr. Edward Ash, “On the action of Metals ... upon water,” in letter to Humboldt, April 10, 1796.

A.D. 1800.—Grout (Jonathan, Jr.), of Belchertown, Mass., takes out, October 24, the first telegraph patent in the United States. It was for a contrivance which he operated between Martha’s Vineyard and Boston, about ninety miles’ distance, from hilltop to hilltop, and which was sighted by telescopes (“Telegraph in America,” J. D. Reid, 1887, p. 5; also “Growth of Industrial Art,” Washington, 1888, p. 55).

A.D. 1800.—Cruikshanks (William), of Woolwich, England, confirms Nicholson and Carlisle’s experiments, and, in his further prosecution of them, employs a pile consisting of from forty to a hundred pairs of zinc and silver plates, as well as a tube holding silver terminals or electrodes, in place of the platinum electrodes, which they were first to make use of.

He discovers that hydrogen is always evolved from the silver or copper end of the voltaic pile and oxygen from the other; that, under like circumstances, metals can be “completely revived” from their solutions; that pure oxygen is freed when a wire of non-oxidable metal, like gold, is connected with the zinc plate, and that fluids that contain no oxygen cannot transmit the voltaic current. These results were verified by Lieut. Col. Henry Haldane, whose many observations upon the series of metals best suited to the production of voltaic electricity and their respective powers in connection therewith are related at pp. 242 and 313, Vol. IV of Nicholson’s Journal for Sept. and Oct. 1800.

Cruikshanks was also the first to discover, in 1800, that when passing the electric current through water tinged with lithmus, the wire connected with the zinc end of the pile imparted a red tinge to the fluid contiguous to it, and that by using water coloured with Brazil wood, the wire connected with the silver end of the pile produced a deeper shade of colour in the surrounding fluid, whence it appeared that an acid was formed in the former case, and an alkali in the latter. Fahie, who thus mentions the fact, justly remarks that upon this discovery are dependent the electro-chemical telegraphs proposed by Bakewell, Caselli, Bonelli, D’Arlincourt, Sawyer and others.

Cruikshanks is the inventor of the galvanic trough, an improvement upon the voltaic pile, made by soldering together rectangular plates of zinc and copper, and so arranging them horizontally, in a box of baked wood coated with an insulating substance, as to allow of open spaces which can be filled with a solution of salt and water or with diluted acid, to take the place of the wet plates of cloth, paper or pasteboard. Cruikshanks’ plan was adopted in the construction of the powerful battery of 600 pairs, which Napoleon Bonaparte presented to the Ecole Polytechnique and upon which Gay-Lussac and Thénard made their important experiments during the year 1808. As Noad remarks, it is a very convenient form when sulphate of copper is used, for Dr. Fyfe has shown (Phil. Mag., Vol. XI. p. 145) that this exciting agent increases the electro-chemical intensity of the electric current as compared with that evolved by dilute sulphuric acid in the proportion of 72 to 16.

Both the above and Volta’s form of battery were much improved upon by Dr. William Babington (1756–1833), who united the pairs of zinc and copper plates by soldering them at one point, and by attaching them to a strip of wood in such a manner as to allow of the entire line being immersed at will into an earthenware or wooden trough having a corresponding number of cells or partitions. The extraordinarily strong voltaic battery, constructed in 1808 for the Royal Institution of London, by Mr. Eastwick under the direction of Sir Humphry Davy and of John George Children, was built upon this plan. It consisted of 200 separate parts, each part being composed of ten double plates, in all 2000 double plates of zinc and copper with a total surface of 128,000 square inches, and the charge which William H. Pepys was accustomed to give it consisted of a mixture of 1168 parts of water, 108 parts nitrous acid, and 25 parts sulphuric acid.

References.—Wilkinson, “Elements of Galvanism,” 1804, Vol. II. pp. 52–63, 96–99; Pepper, “Electricity,” 1809, pp. 313–315; Noad, “Manual,” pp. 263, 264; Tomlinson, “Cyclopædia of Arts,” Vol. I. p. 566; Napier, “Electro-Metallurgy,” 1853, pp. 27, 28; Nicholson’s Journal, Vol. IV. pp. 187, 254, 261 and 511; Sturgeon’s Annals, Vol. IX. p. 309; Cruikshanks, “Some Experiments and Observations on Galvanic Electricity,” July 1800; also “Additional Remarks on Galvanic Electricity,” September 1800.

A.D. 1801.—Davy (Humphry), a very eminent English chemical philosopher, whose early studies had been greatly influenced both by Dr. John Tonkin, of Penzance, and by Gregory Watt, son of the celebrated inventor, James Watt, as well as by Mr. Davies Giddy Gilbert, who brought him to the notice of the English Royal Institution, delivers before the latter body, on the 25th of April 1801, his first lecture, wherein he traces the history of galvanism, and describes the different methods of “accumulating” it.

His first communication to the Royal Society was made in June of the same year, and is entitled, “An Account of Some Galvanic Combinations Formed by the Arrangement of Single Metallic Plates and Fluids, Analogous to the New Galvanic Apparatus of Volta.” As his able biographer, Prof. T. James Stewart Traill, M.D., of Edinburgh, remarks, this paper is the first of that series of electro-chemical investigations which have immortalized his name. In all hitherto constructed piles, the series had consisted of not less than two metals, or of one plate of metal, another of charcoal, and some interposed fluid. He showed in this paper that the usual galvanic phenomena might be energetically exhibited by a single metallic plate and two strata of different fluids, or that a battery might be constructed of one metal and two fluids, provided one of the fluids was capable of causing oxidation on one of the surfaces of the metal (“Bakerian Lectures,” London, 1840, pp. 32, etc., and Phil. Trans., Vol. XCI. p. 297).

On the 20th of November 1806 was read before the Royal Society Davy’s first Bakerian lecture, “On Some Chemical Agencies of Electricity.” This essay was universally regarded as one of the most valuable contributions thus far made to chemistry, and obtained for Davy the prize founded by Napoleon when First Consul, to be awarded by the French Institute, “à celui, qui par ses expériences et ses découvertes, fera faire a l’électricité et au galvanisme un pas comparable à celui qu’ont fait faire à ces sciences Franklin et Volta” (“Bakerian Lectures,” 1840, p. 56, and notes at p. 349, Vol. I of Dr. Lardner’s “Lectures,” etc., 1859).

Of the French Institute Davy became a member in 1817. Regarding the above-named important paper, given in full at pp. 1–56, of the volume of “Bakerian Lectures,” already referred to, Davy says (Phil. Trans. for 1826, p. 389): “Referring to my experiments of 1800, 1801 and 1802, and to a number of new facts, which showed that inflammable substances and oxygen, alkalies and acids, and oxidable and noble metals, were in electrical relations of positive and negative, I drew the conclusion that the combinations and decompositions by electricity were referable to the law of electrical attractions and repulsions,” and advanced the hypothesis “that chemical and electrical attractions were produced by the same cause, acting in the one case on particles; in the other on masses; ... and that the same property, under different modifications, was the cause of all the phenomena exhibited by different voltaic combinations” (Vol. I. pp. 678–684 of Dr. Thomas Young’s “Course of Lectures,” London, 1807, on “Electricity in Motion,” also Dr. Henry M. Noad’s “Manual,” London, 1859, pp. 362–365).

The second Bakerian lecture, “On some new phenomena of chemical changes produced by electricity, particularly the decomposition of the fixed alkalies, and the exhibition of the new substances which constitute their bases; and on the general nature of alkaline bodies,” was read Nov. 19, 1807. In this he gives an account of the most brilliant of all his discoveries (made during the previous month), proving that the so-called fixed alkalies are merely combinations of oxygen with metals. It has been stated by Dr. John Ayrton Paris that since the days of Newton no such happy and successful instance of philosophical induction has ever been afforded as that by which Davy reached the above-named results (Phil. Trans. for 1808, Vol. XCVIII. pp. 1–44). Davy’s observations were fully confirmed by Gay-Lussac, Thénard, Berzelius and Pontin (Annales de Chimie, Vol. LXXII. p. 193; Vol. LXXV. pp. 256–291; Bibl. Brit. for June 1809, p. 122). Although Davy was less successful in his attempt to decompose the proper earths, he proved that they consist of bases united to oxygen. It was reserved for Friedrich Wöhler, Berzelius and Bussy to exhibit the bases by themselves, and to show that all, excepting silica, are metallic, and capable of uniting with iron.

It is said that the original 500-plate batteries of the Royal Institution were so worn in the course of Davy’s experiments as to be almost unserviceable, and that he suggested to the managers the propriety of starting a subscription for the purchase of a large galvanic battery. This being acted upon during the month of July 1808, he was placed in possession of the battery already alluded to in the Cruikshanks article (A.D. 1800), and which was the most powerful constructed up to that time. “With this battery Davy did not reach any new results of importance; but he was enabled to demonstrate the galvanic phenomena upon a more brilliant scale. Nor was the increased power necessary to carry on successfully the experiments on the decomposition of the alkalies and the earths as was apparently believed by many of those historians of science ... who attributed the author’s brilliant success in electro-chemical research to his supposed extraordinary means, the enormous voltaic batteries of the Royal Institution.” In this connection, the terse notes appearing at foot of pp. 62, 63, 106, 107 of the 1840 edition of the “Bakerian Lectures” will prove interesting reading.

It was with the afore-named galvanic combination that Davy openly made—in 1809–1810, and not in 1813, as has been frequently stated—the first display of the continuous electric arc (John Davy, “Memoirs of the Life of Sir Humphry Davy,” p. 446).

“When the cells of this battery were filled with sixty parts of water mixed with one part of nitric acid and one part of sulphuric acid,” he says, “they afforded a series of brilliant and impressive effects. When pieces of charcoal about an inch long and one-sixth of an inch in diameter were brought near each other (within the thirtieth or fortieth part of an inch), a bright spark was produced, and more than half the volume of the charcoal became ignited to whiteness, and by withdrawing the points from each other a constant discharge took place through the heated air, in a space equal at least to four inches, producing a most brilliant ascending arch of light, broad and conical in form in the middle. When any substance was introduced into this arch, it instantly became ignited; platina melted as readily in it as wax in the flame of a common candle; quartz, the sapphire, magnesia, lime, all entered into fusion; fragments of diamond, and points of charcoal and plumbago, rapidly disappeared, and seemed to evaporate in it, even when the connection was made in a receiver exhausted by the air pump; but there was no evidence of their having previously undergone fusion” (“Elements of Chemical Philosophy,” 1812, p. 154).

Dr. Paris says that Davy had already produced the spark upon a small scale as far back as 1800 (Nicholson’s Journal, Vol. III, quarto, p. 150), and we learn, through an article published upon the early experiments with the electric light, the names of others who had likewise noticed the arc at about the same period, while Quetelet informs us that M. Curtet is reported to have observed the light between carbon points during the year 1802 (Curtet’s letter to J. B. Van Mons in the latter’s Journal de Chimie, No. VI. p. 272, and in Journal de Physique, An. XI. p. 54). The article referred to is as follows:

“Dr. S. P. Thompson has given the following interesting details in regard to this subject: In looking over an old volume of the Journal de Paris, I found, under date of the Twenty-second Ventose, An. X (March 12, 1802), this passage, which evidently refers to an exhibition of the electric arc: ‘Citizen (E. G.) Robertson, the inventor of the phantasmagoria (magic lantern), is at present performing some interesting experiments that must doubtless advance our knowledge concerning galvanism. He has just mounted metallic piles to the number of 2500 zinc plates and as many of rosette copper. We shall forthwith speak of his results, as well as of a new experiment that he performed yesterday with two glowing carbons. The first having been placed at the base of a column of 120 zinc and silver elements, and the second communicating with the apex of the pile, they gave at the moment they were united a brilliant spark of an extreme whiteness that was seen by the entire society. Citizen Robertson will repeat the experiment on the 25th.’”

The date generally given for this discovery by Humphry Davy is 1809, but earlier accounts of his experiments are found in Cuthbertson’s “Electricity” (1807), and in several other works.

In the Phil. Mag., Vol. IX. p. 219, under date of Feb. 1, 1801, in a memoir by Dr. H. Moyes, of Edinburgh, relative to experiments made with the pile, we find the following passage: “When the column in question had reached the height of its power, its sparks were seen by daylight, even when they were made to jump with a piece of carbon held in the hand.” In the same volume of the Phil. Mag., and immediately following Dr. Moyes’ letter to Dr. Garthshore, on experiments with the voltaic pile, will be found an account of similar investigations made in Germany, and communicated by Dr. Frulander, of Berlin.

In the “Journal of the Royal Institution” (1802), Vol. I. p. 106, Davy describes a few experiments made with the pile, and says: “When instead of metals, pieces of well-calcined carbon were employed, the spark was still larger and of a clear white.” On p. 214 he describes and figures an apparatus for taking the galvano-electric spark into fluid and aeriform substances. This apparatus consisted of a glass tube open at the top, and having at the side another tube through which passed a wire that terminated in a carbon. Another wire, likewise terminating in carbon, traversed the bottom, and was cemented in a vertical position.

But all these observations are subsequent to a letter printed in “Nicholson’s Journal” for October 1800, p. 150, entitled “Additional experiments on Galvanic Electricity in a letter to Mr. Nicholson.” The letter is dated Dowry Square, Hotwells, Sept. 22, 1800, and is signed by Humphry Davy, who at this epoch was assistant to Dr. Beddoes at the Philosophical (Pneumatic) Institution of Bristol. It begins thus:

“Sir: The first experimenters in animal electricity remarked the property that well calcined carbon has of conducting ordinary galvanic action. I have found that this substance possesses the same properties as metallic bodies for the production of the spark when it is used for establishing a communication between the extremities of Signor Volta’s pile.”

Among the papers read by Davy before the Royal Society between June 30, 1808, and Feb. 13, 1814, are the following: “Electro-chemical researches on the decomposition of the earths, with observations on the metals obtained from the alkaline earths, and on the amalgam procured from ammonia”; “An account of some new analytical researches on the nature of certain bodies,” etc., and the Bakerian lecture “On some new electro-chemical researches, on various objects, particularly the metallic bodies from the alkalies and earths, and on some combinations of hydrogen”; “Elements of chemical philosophy, detailing experiments on electricity in vegetation.”

In alluding to the important subjects covered by him during the above-named period, his brother and biographer, John Davy, M.D., F.R.S., says: “I shall not attempt an analysis of these papers; I shall give merely a sketch of the most important facts and discoveries which they contain, referring the chemical reader to the original for full satisfaction. After the extraction of metallic bases from the fixed alkalies, analogies of the strongest kind indicated that the alkaline earths are similarly constituted; and he succeeded in proving this in a satisfactory manner. But, owing to various circumstances of peculiar properties, he was not able on his first attempts to obtain the metals of those earths in a tolerably pure and insulated state for the purpose of examination. On his return to the laboratory after his illness, this was one of the first undertakings. He accomplished it to a certain extent by uniting a process of Messrs. Berzelius and Pontin, who were then engaged in the same enquiry, with one of his own. By negatively electrifying the earths, slightly moistened, and mixed with red oxide of mercury, in contact with a globule of mercury, he obtained amalgams of their metallic bases; and, by distillation, with peculiar precautions, he expelled the greater part of the mercury. Even now, in consequence of the very minute quantities of the bases which he procured, and their very powerful attraction for oxygen, he was only able to ascertain a few of their properties in a hasty manner. They were of silvery lustre, solid at ordinary temperatures, fixed at a red heat, and heavier than water. At a high temperature they abstracted oxygen from the glass, and, at ordinary temperatures, from the atmosphere and water, the latter of which in consequence they decomposed. The names he proposed for them, and by which they have since been called, were barium, strontium, calcium and magnium, which latter he afterwards altered to magnesium....”

The reviewer of Davy, in the columns of the “Chemical News,” writing in 1879, states that his papers on numerous subjects flowed into the Royal Society’s archives in an uninterrupted stream, and it may be said, without exaggeration, that his work, especially during the six years from 1806 to 1812, did more for chemistry than the 60 which followed them.

Between the last-named dates, Davy was asked by the Dublin Society to give a course of lectures on electro-chemical science, which he delivered Nov. 8–29, 1810. Trinity College afterward conferred on him the degree of LL.D., and he was knighted by the Prince Regent one day before resigning from the Royal Institution, wherein he gave his farewell address on April 9, 1812.

In 1813, accompanied by his bride and Mr. Faraday (his “assistant in experiments and in writing”), Davy made his first trip to the Continent, where he met Ampère, Humboldt, Gay-Lussac, Vauquelin, Cuvier, Laplace and other distinguished scientists, and where he carried on many experiments, of which the results were duly communicated to the Royal Society, as were also the observations made by him up to the time of the completion of his second trip in 1820.

Besides the Rumford medal conferred on him in 1816, he received a baronetcy two years later, and was given, in 1827, the medal of the Royal Society, the presidential chair of which he occupied for seven consecutive years.

One of the four memoirs produced by Davy in 1818–1829 treats of electro-magnetism. In 1820, Davy, Arago and Seebeck independently discovered the magnetizing power of the electric current on steel and iron needles or filings. In Davy’s experiments, it is said, the filings adhered to the wire connecting the poles of a voltaic apparatus, consisting of a hundred pairs of plates of four inches, in such considerable quantities as to form a mass around it ten or twelve times the thickness of the wire (Phil. Trans. for 1821, p. 9; Annales de Chimie et de Physique, Vol. XV. p. 93).

Davy was actively engaged during 1821–1822 in experiments on electro-magnetism and on electricity in vacuo, reaching the conclusion, in the last-named channel, that electric light as well as electrical attractions and repulsions are observable in the most perfect vacuum obtainable. This is readily demonstrated with either the apparatus employed by Tyndall in his Lecture VIII, “On the analogies of light, heat and sound,” or with the apparatus used by Davy and illustrated at Plate CCXXIII of the “Encyclopædia Britannica,” eighth edition. From the numerous experiments and observations recorded in the last-named work the following are extracted:

“A spark capable of passing through only half an inch in common air will pass through six inches of the Torricellian vacuum.... When the minutest quantity of rare air was introduced into the mercurial vacuum, the colour of the electric light changed from bright green to sea green, and by increasing the quantity, to blue and purple. At a low temperature the vacuum became a much better conductor. A vacuum above fused tin exhibited nearly the same phenomena. At temperatures below zero the light was yellow and of the palest phosphorescent kind, just visible in great darkness, and not increased by heat. When the vacuum was formed by pure olive oil and by chloride of antimony, the electric light through the vapour of the chloride was more brilliant than that through the vapour of the oil; and in the last it was more brilliant than in the vapour of mercury at common temperatures. The light was of a pure white with the chloride, and of a red inclining to purple in the oil.... In carbonic acid gas the light of the spark is white and brilliant, and in hydrogen gas it is red and faint. When the sparks are made to pass through balls of wood or ivory they are of a crimson colour. They are yellow when taken over powdered charcoal, green over the surface of silvered leather, and purple from imperfect conductors.”

Davy’s Bakerian lecture for 1826 was entitled “On the relation of electrical and chemical changes.” Two years previous to its reading he had communicated to the English Government his discovery of what he erroneously considered a remedy against the rapid deterioration of copper sheathing for ships. His plan consisted in altering the electrical condition of the copper by adding plates of zinc or iron (called “protectors”), but the bottoms of the vessels became so foul through the deposition of calcareous matter and the adhesion of large balani and lepades, etc., to the copper, that the attempt had to be abandoned (A. Bobierre, “Thèse ... pour doubler les navires,” Nantes, 1858). It was in the same year (1824) that Davy made an important journey through Sweden, Norway, Denmark, Holstein, and Hanover, during which he met Oersted, Berzelius, Gauss, Olbers, Schumacher and other savants.

His last communication to the Royal Society, “Remarks on the Electricity of the Torpedo,” was sent from Rome in 1828, one year before his death, and embodies the result of many observations made while on the Continent, more especially during the years 1814–1815. The investigations in this line which, owing to continued ill health, he was unable to carry on, were completed by his brother, Dr. John Davy, who established the following points of difference between the phenomena of the torpedo and those of other kinds of electricity:

“Compared with voltaic electricity, its effect on the multiplier is feeble: its power of decomposing water and metallic solutions is inconsiderable; but its power of giving a shock is great, and so also is its power of magnetizing iron. Compared with common electricity, it has a power of affecting the multiplier, which, under ordinary circumstances, common electricity does not exhibit; its chemical effects are more distinct; its power of magnetizing iron and giving a shock appears very similar; its power of passing through air is infinitely less as is also (if it possess it at all) the power of producing heat and light.”

Davy likewise made noteworthy observations concerning the pyro-electricity of the tourmaline, confirming previous investigations in the same line, and asserting that “when the stone is of considerable size, flashes of light may be seen along its surface” (“Elements of Chemical Philosophy,” Vol. I. p. 130), a curious fact which Sir David Brewster says he does not believe has ever been verified by any subsequent observer.

It is not within the scope of this “Bibliographical History” to describe Davy’s other notable papers relative to the miner’s safety lamp, etc., but reference should be made here to his first scientific memoir, “On heat, light and the combination of light” (Sir H. Davy’s works, Vol. II) of which copious extracts are given by Prof. John Tyndall in the appendix to his third lecture on “Heat considered as a mode of motion.”

As regards the caloric theory, which had deservedly been engaging the attention of so many scientists, it is, however, thought best to quote here from Deschanel’s article on thermo-dynamics: “Strange to say, this theory survived the many exposures of its weakness and the, if possible, still more conclusive experiment of Sir Humphry Davy, who showed that two pieces of ice, when rubbed together, were converted into water, a change which involves not the evolution but the absorption of latent heat, and which cannot be explained by diminution of thermal capacity, since the specific heat of water is much greater than that of ice. Davy, like Rumford, maintained that heat consisted in motion, and the same view was maintained by Dr. Thomas Young; but the doctrine of caloric nevertheless continued to be generally adopted until about the year 1840, since which time the experiments of Joule, the eloquent advocacy of Meyer, and the mathematical deductions of Thomson, Rankine and Clausius, have completely established the mechanical theory of heat, and built up an accurate science of thermo-dynamics.”

References.—“The Life of Sir H. Davy,” by John Ayrton Paris, M.D., 1831, and by T. E. Thorpe, New York, 1896, also his life by Dr. John Davy, F.R.S., 1836; and his biography and articles “Chemistry” and “Voltaic Electricity” in the “Encyclopædia Britannica”; “Works of Sir Humphry Davy,” edited by John Davy, 1839–1840; “The Fragmentary Remains ... of Sir H. Davy,” 1858; “Dic. Tech. et Prat. d’Electricité” de Mr. Geo. Durant, Paris, 1887–1889; W. T. Brande, “Manual of Chemistry,” London, 1848, Vol. I. pp. xciii-cv, 213–224; C. H. Wilkinson, “Elements of Galvanism,” London, 1804, Vol. II. pp. 80–86, and Chap. XXVII; Thomas Thomson, “History of the Royal Society,” London, 1812, pp. 454–455; “Galvanism,” in Dr. Lardner’s Lectures; Noad’s “Lectures on Chemistry,” pp. 32–33; Bakewell’s “Elec. Sc.,” pp. 33–35; Daniel Davis, “Manual of Magnetism,” 1846–1852; Thomson, “History of Chemistry,” Vol. II. pp. 260–261; “Elem. of Exp. Chem.,” Wm. Henry, London, 1823, Vol. I. p. 192; “Elements of Chemical Philosophy,” p. 155; Thomas Thomson, M.D., London, 1830; “Outline of the Sciences of Heat and Electricity,” pp. 467, et. seq., 491–495, 533; De la Rive’s “Treatise on Electricity ...” Vol. II. pp. 282–283; “Encyclopedia Metropolitana,” Vol. IV (Galv.), pp. 176, 178, 222, and (Elec. Mag.) pp. 9 and 10; Gay-Lussac and Thénard, Phil. Mag., Vol. XXXII. p. 88, 1809; Jacquin, Phil. Mag., Vol. XXXVI. p. 73, 1810; M. Donovan, Phil. Mag., Vol. XXII. pp. 227, 245, 1811; M. Yatman, “A Letter ...” and Davy’s “Enquiries ...” London, 1811, 1814; W. Henry, “On Sir H. Davy and Dr. Wollaston,” London, 1830; Contessi G. Lelandri, “Ann. Reg. Lomb., Veneto,” 11, 78, 1832, and F. I. Roux, “Conservation des plaques ...” Paris, 1866; Nicholson’s Journal, 4to, Vol. IV. pp. 275, 337 and 394; and 8vo., Vol. I. p. 144, Vol. III. p. 135; Dredge, “Electric Illumination,” Vol. I. pp. 24, 25, 30; Phil. Mag., Vol. VII. p. 347, for experiments of Dr. Henry Moyes, also Vol. XI. pp. 302, 326; XXVIII. pp. 3, 104, 220; XXIX. p. 372; XXXI. p. 3; XXXII. pp. 1, 18–22, 101, 146, 193; XXXIII. p. 479; XXXV. p. 401; XXXVI. pp. 17, 85, 352, 404; XL. p. 145; LVIII. pp. 43, 406; LIX. p. 468; LX. p. 179; Phil. Mag. or Annals, Vols. I. pp. 31, 94, 190; VI. p. 81; X. pp. 214, 379, 426; Phil. Trans. for 1801, 1809, 1810, 1822; Sturgeon’s “Scientific Researches,” Bury, 1850, pp. 14–16, 23; Annales de Chimie, Vol. XV. p. 113; “Société Philomathique,” An. X. p. 111; Becquerel, Paris, 1850, Vol. I. pp. xi and 33 note; “Nuova Scelta d’Opusc.” Vol. II. pp. 190, 282; “Beiträge zur Erweiterung,” etc., Berlin, 1820; “Elemente d. Chemischen,” etc., Berlin, 1814; “Royal Society Catalogue of Scientific Papers,” London, 1868, Vol. II. pp. 171–175; “Biographie Générale,” Vol. XIII. p. 264; “Engineering,” London, Vol. LII. p. 759; “Abstracts of Papers ... Roy. Soc.,” London, 1832–1833, Vol. I. pp. 59, 247, 278, 313, 350; Vol. II. pp. 154, 159, 189, 213, 242, 281, 354; “Royal Society Catalogue of Scientific Papers,” Vol. II. pp. 175–180, and Vol. VI. p. 633 (likewise Vol. VII. pp. 494–495—for John Davy); “Bibliothèque Britannique,” Vol. XVII for 1801, pp. 237, 246; Vol. XXV, N.S. for 1824, p. 98; Vol. XXXIV, O.S. for 1807, p. 397 (the same as “Nicholson’s Journal,” for January 1807); Vol. XXXV. pp. 16, 141; “Edin. Phil. Journ.,” Vol. X. p. 185.

Of the afore-named references in the Phil. Magazine, Vol. XXXI, that at p. 3 relates to Davy’s new Eudiometer acting by the electric spark exactly in the same manner as that of Il Marchese de Brezé, described in the “Opuscoli.”

A.D. 1801.—Flinders (Matthew), a very able navigator and captain in the English merchant service, sails in the bark “Investigator” for the purpose of circumnavigating and exploring New Holland. During this memorable voyage he carefully observed the cause of errors in the variation of the magnetic needle as depending on the direction in azimuth of the ship’s head, having often noticed, as a writer in the English Quarterly Review expresses it (Vol. CXVIII. p. 343), that the direction of the compass needle frequently wandered from that which the known variation due to the geographical position of the ship assigned to it. To correct those disturbances he suggested placing aft of the compass a vertical bar of soft iron, whose upper end, having like magnetism as the imaginary mass in the ship’s head, would, in acting on the opposite pole of the compass needle, rectify its disturbances.

Flinders had, during the year 1795, made observations in the same line as those recorded by the astronomer Bayly, who had sailed with Captain Cook during his last two voyages, but it was not until his return from the unfortunate first voyage above alluded to that he properly recorded his investigations for the benefit of navigators.

References.—“Encyclopædia Britannica,” 1856, Vol. X. p. 295, and article “Australia,” Vol. IV. pp. 253, 254; “English Cyclopædia” (Biography), Vol. II. pp. 933–935; Sci. Am. Supp., No. 534, p. 8526; William Walker, “The Magnetism of Ships,” London, 1833, pp. 21–23; “Abstracts of Papers of the Phil. Trans., 1800–1830,” p. 187; Phil. Trans. for 1805; John Farrar, “Elem. of Elect.,” 1826, p. 381; “Cat. Sc. Papers Royal Soc.,” Vol. I. p. 187.

A.D. 1801.—Gautherot (Nicholas), able French chemist (1753–1803), discovers that when a current has passed through two plates or wires of the same metal in dilute sulphuric acid, a secondary, reverse or polarization current is obtainable after disconnecting the battery. This was the first step in the storage of electricity and an account is given of it in the Philosophical Magazine, Vol. XXIV. pp. 185–186, which contains a report of the proceedings before the Galvani Society of Paris. Gautherot says that the results he obtained should become the source or basis of several other experiments, and concur more than any other to the discovery of the theory of this new branch of physics.

In this same year Gautherot observed the power of adhesion of the two wires in contact with the upper and lower ends of the pile, a report upon which appears at p. 209, Vol. XXXIX of the Annales de Chimie, while a full account of his observations on the subject forms the substance of a separate work printed in London during the year 1828.

The French physicist, C. J. Lehot, makes allusion to the last-named discovery in the following words, at p. 4 of his pamphlet entitled “Observations sur le Galvanisme et le Magnétisme”:

“It has long been known that the two wires which terminate a pile attract one another, and, after contact, adhere like two magnets. This attraction between the two wires, one of which receives, and the other loses, the galvanic fluid, differs essentially from electrical attraction, as Ritter observed, since it is not followed by a repulsion after contact, but continues as long as the chain is closed.”

J. J. Fahie, who also quotes this passage, says:

“The discovery in question seems to have been made independently, and at about the same time by Gautherot (Philosophical Magazine or Annals for 1828, Vol. IV. p. 458), by P. S. Laplace, and by J. B. Biot (Journal de Physique et de Chimie, for 1801, Vol. LIII. p. 266). The latter made the further very acute observation that, if the wires are attached to plates of metal, and these plates approached by their edges, they will attract one another; while if approached by their faces no action whatever takes place. For other interesting experiments of this kind see ‘Nicholson’s Journal’ for 1804, Vol. VII. p. 304.”

Previous to the aforesaid discoveries, on the 12th Brumaire, An. IX (Nov. 1800), Gautherot had published his refutation of Volta’s contact theory, through the Paris “Société Philotechnique,” and it is to be found recorded at p. 471, Vol. I of the “Mémoires des Sociétés Savantes et Littéraires de la République Française.”

Later on he devoted so much attention to galvanic researches that Messrs. A. F. de Fourcroy and L. N. Vauquelin made a special report upon the five important memoirs containing the results of his many observations to the French Institute on the 21st Fructidor.

The first memoir gives the whole theory and practice of the various kinds of conductors, and describes an apparatus devised by Gautherot to ascertain the conducting powers of different natural, solid, liquid and even gaseous bodies (Izarn, “Manuel du Galvanisme” 1804, pp. 56–60). He enters into full details as to the effects of the voltaic pile in many experiments made upon himself, and draws consequences which apparently disprove the identity of the electric and the galvanic fluids.

The second memoir treats of the galvanic properties of charcoal, and shows that it is a less perfect conductor than are metallic substances.

In the third memoir he makes known his discovery that charcoal and zinc form a galvanic apparatus which will produce shocks, the decomposition of water, etc. He observes “that in the decomposition of water, charcoal decomposes that fluid in the same way with non-oxydable metals; or, in other words, that when two pieces of charcoal are employed for this purpose, one of them disengages the hydrogen gas, and the other the oxygen ... when the portions of charcoal touch each other in the water, its decomposition is not stopped on that account, as happens when metallic substances are brought in contact under the same circumstances. Indeed, if to bring more immediately together, one of the pieces of charcoal be cut in a furcated shape, this does not become an obstacle to the decomposition of the water.”

The fourth memoir treats further of different kinds of conductors, and of various methods of constructing galvanic columns.

In the fifth and last memoir, Gautherot relates his important discovery that an effective galvanic apparatus can be made without metals. He constructed one of forty layers of charcoal and plumbago, which communicated a strong and pungent taste, accompanied by the galvanic flash of light, and which finally produced the decomposition of water, the charcoal side disengaging the hydrogen gas (Izarn, “Manuel du Galvanisme,” 1804, p. 177).

During the month of March 1803, he read before the “Institut National” a memoir entitled “Recherches,” etc. (researches upon the causes which develop electricity in the galvanic apparatus). This appeared in the Journal de Physique, Vol. LVI. p. 429.

References.—“Biographie Générale,” Vol. XIX. p. 694; Larousse, “Dict. Univ.,” Vol. VIII. p. 1089; Izarn, Giuseppe (Joseph) “Manuel du Galvanisme,” Paris, An. XII. 1804, s. 6, pp. 95, 250–254: Mém. des Soc. Savantes, etc., Vol. I. pp. 164, 168; P. Sue, aîné, “Hist. du Galvanisme,” Paris, An. X, 1802, Vol. II. pp. 191, 196–203, 213, 214, 316; Alglave et Boulard, Lumière Electrique, Paris, 1882, p. 219; Poggendorff, Vol. I. p. 857; “Extrait d’une lettre de Brugnatelli,” etc., Bruxelles, 1802 (Van Mons, Journal de Chimie, Vol. II. p. 216).

A.D. 1801.—Robertson (Etienne Gaspard), a very capable French experimentalist and one of the founders of the Paris Galvani Society, who has already been alluded to in the article relating to Sir Humphry Davy, writes a memoir, “Expériences nouvelles sur le fluide galvanique,” which was read before the Institute on the 11th Fructidor, An. VIII, and which appeared in the Annales de Chimie (Vol. XXXVII. p. 132), as well as in the “Mémoires Récréatifs, Scientifiques,” etc., published in Paris during 1840, three years after Robertson’s death.

Robertson states that as he was delivering a lecture on the 9th Vendémaire, An. IX, during which he alluded to differences which he found to exist between the galvanic and electric fluids, he was interrupted by Prof. Brugnatelli, who stated that Volta, who was then present, desired an opportunity to correct the wrong impressions the lecturer laboured under. Volta called upon him early the day following and brought a live frog as well as apparatus, with which they experimented quite extensively, and the results of which brought Robertson completely over to the views of the Italian scientist. Volta frequently repeated his visits, which led to the development of a lasting friendship between the two. They visited together all the prominent scientific bodies, such as l’Ecole de Médecine, l’Ecole Polytechnique, etc., but found to their great astonishment that Robertson was the only one in Paris who had as yet given the new discovery any serious attention. At pp. 250–253, Vol. I of his “Mémoires,” etc., will be found a full account of the above as well as of the very indifferent reception first given them by the celebrated Prof. Charles.

Robertson adds (p. 256 of last-named work) that he was asked by Volta to witness the latter’s notable experiments made before the members of the National Institute of France, Nov. 16, 18, 20, 1800, and already alluded to herein at A.D. 1775. The sessions of that body were being held at the time in the Palais du Louvre, and the excitement caused by the meetings was so great that all the approaches were guarded by soldiery. After Prof. Volta had explained his theory and alluded to the identity of electricity and galvanism, he announced that Robertson had first illustrated the fact, and he asked him to repeat his original experiment, which the latter did after the necessary hydrogen gas had been procured from the neighbouring cabinet of Prof. Charles.

Robertson is also the author of several other interesting memoirs on the electrophorus, the improved “couronne de tasses” and “acide galvanique” which can be found in Vol. XXXVII of the Journal de Physique and in the Journal de Paris for the year 1800 (“Recueil des Actes de la Soc. de Lyon,” Tome II. p. 370).

A.D. 1801.—Gerboin (A. C.), Professor at the Medical School of Strasbourg, is the first to report upon the peculiar agitation of mercury when the voltaic current passes through it.

He states, in his “Recherches expérimentales sur un nouveau mode de l’action électrique” (Strasbourg, 1808), that his many researches were instigated by the observation he had made during the winter of 1798, while in company with some friends watching a child play with a hollow wooden ball. The Italian physicist, Abbate Fortis (1740–1803), who wrote several works on natural philosophy, but who is best known by his “Viaggio di Dalmazia,” had already announced that a pyritical cube suspended by a thread held between the thumb and index would immediately, without any movement of the fingers, assume a circular motion upon being approached by another body. The “Morgenblatt” of Tübingen and the French “Archives Littéraires” render in 1807 a very complete account of Ritter’s researches upon the Fortis pendulum, and N. Meissas states, at pp. 181–187 of his “Nouveaux Eléments de Physique,” Paris, 1838, that he repeated the experiment of Ritter and of his friend Gerboin and observed many very curious results. These he embodied in a communication during the month of April 1829 to Ampère, who looked into Meissas’ work in company with M. Becquerel, also a member of the French Institute.

In his experiments, Gerboin employed a tube bent in U[** symbol] form, filled half full of mercury, which later was covered with a stratum of water, and he placed therein the wires connecting with a pile. The surface of the mercury beneath the negative pole was slightly oxidized, but the surface under the positive point moved so violently as to cause small bodies placed within to be thrown outward upon the surface of the tube. These bodies moved in a contrary direction, v from the circumference toward the interior, if the positive pole was made to touch the liquid metal.

References.—Observations of M. Erman, of the Berlin Academy of Sciences, upon M. Gerboin’s experiments related in the Annales de Chimie, Tome LXXVII. p. 32. Also, Annales de Chimie, Tome XLI. pp. 196, 197, Mém. des Soc. Sav. et Lit., Vol. II. p. 199; Dr. Gore, “El. Metal,” 1877, p. 3; De la Rive, “Treatise on Electricity,” 1856, Vol. II. p. 433; Gmelin’s “Chemistry,” Vol. I. p. 487.

A.D. 1801.—Trommsdorff (Johann Bartholomäus), German chemist and pharmacist, who became Professor of Physics and Chemistry in the University of Erfurt, discovers that by employing large plates in galvanic batteries he can produce the combustion of fine wires and of thin leaves of metal.

After having obtained very strong shocks and large sparks, and effected the decomposition of water, etc., with his first pile consisting of 180 discs of copper, zinc and wet cardboard, he experimented with very thin leaves of the following metals, and found them to burn as follows: Gold, with a bright white light; silver, with a blue light; yellow copper, with a reddish blue light; red copper, with an emerald blue flame; zinc, with a bluish white flame; tin, with a reddish white light, etc. When oxidizing the noble or perfect metals, gold, silver, platinum, in hollow glass spheres, he found them to melt so thoroughly as to completely line the sides of the latter.

Trommsdorff afterward constructed a much larger pile of nearly 600 discs, not doubting that with a larger apparatus he could consume very thick plates. It was while carrying on subsequent experiments that MM. Fourcroy, Vauquelin and Thénard ascertained the fact that metals were more effectively deflagrated by piles with large plates than by piles having a great many plates of smaller surfaces.

In a letter dated Erfurt, March 16, 1801, Trommsdorff alludes to the galvanic decomposition of water spoken of at p. 98 of the “Archives du Nord pour la Physique et la Médecine,” published at Copenhagen, and expresses doubts as to the correctness of the conclusions therein pointed out by Pfaff and Ritter.

References.—“Encycl. Metrop.” (Galvanism), Vol. IV. p. 221; “Roy. Soc. Sci. Papers,” Vol. VI. pp. 45–52; Poggendorff, Vol. II. pp. 1136, 1137; C. H. Wilkinson, “Elem. of Galv.,” London, 1804, Vol. II. pp. 134–136; J. S. Ersch, “Handbuch,” etc., p. 119; L. F. F. Crell, “Chemische Annalen” for 1801; 4^e Cah., p. 337; J. B. Van Mons, Journal de Chimie, Vol. I. p. 41; Larousse, “Dict. Univ.,” Vol. XV. p. 535. His pile is described at pp. 253–254, Vol. II of “Hist. du Galvanisme,” P. Sue, aîné, Paris, An. X, 1802, with references to Von Crell’s “Chemische Annalen,” 1801, 4th Book, p. 237, and Van Mons’ “Journal de Chimie,” Vol. I. p. 41.

A.D. 1801.—Libes (Antoine), Professor of Natural Philosophy at the Collège de Beziers and at the Paris Ecole Normale and Lycée Charlemagne, publishes in three volumes, at Paris, his “Traité élémentaire de Physique,” which had been preceded by his “Théorie de l’électricité,” etc., and was followed by a valuable “Dictionnaire de Physique” in 1806 (C. F. V. Delaunay, “Manuel,” etc., Paris, 1809).

In his “Traité,” Prof. Libes dispels the previous generally accepted belief as to the production of electricity by pressure. Experiments made by Æpinus and by Haüy had shown that such minerals as developed positive electricity by friction likewise exhibited the same electricity by pressure, and that those furnishing resinous or negative electricity by pressure developed the same electricity by friction.

It is known that varnished silk (taffetas gommé) acquires resinous electricity by ordinary friction, but Libes found the means of causing it to develop vitreous or positive electricity. This is shown when a metallic disc insulated by a glass handle is pressed upon the silk; the latter will acquire positive electricity while the disc will develop resinous or negative electricity. If, on the contrary, the disc is rubbed or rolled upon the silk so as to produce friction, the silk acquires resinous electricity and the disc vitreous or positive electricity. If a glass plate is substituted for the disc, the silk again acquires vitreous electricity and the glass resinous electricity, that is to say, they both develop contrary electricities to that furnished through ordinary rubbing.

References.—Larousse, “Dict. Univ.,” Vol. X. p. 475; Poggendorff, Vol. I. pp. 1449, 1450; Volpicelli, “Sul cognito fenomeno ...” Roma, 1859; Haüy, “Traité Elémentaire de Physique,” Paris, 1806, Vol. I. pp. 371, 372; A. C. Becquerel, “Expériences ... par la pression,” Paris, 1823; “Catal. of Sci. Papers of Roy. Soc.,” Vol. IV. p. 5; Thos. Thomson, “An Outline of the Sciences of Heat and Electricity,” London and Edinburgh, 1830, p. 482; Dove, p. 229; “Encycl. Brit.,” Vol. VIII, 1855, p. 563; Annales de Chimie et de Physique, Vol. XXII. p. 5; Phil. Mag., Vol. LXII. pp. 204, 263.

A.D. 1801.—Fourcroy (Antoine François de), an eminent French chemist, physician and author, who succeeded Macquer in the professorship at the Jardin du Roi, for which Lavoisier was likewise a candidate, publishes (Vol. XXXIX. p. 103, of the Annales de Chimie) the result of galvanic experiments which he made in conjunction with Louis Nicholas Vauquelin (1763–1829), and also with Baron Louis Jacques Thénard (1777–1857), who, in turn, became the successor of Fourcroy as Professor of Chemistry at the Ecole Polytechnique. They thought that by using many discs they could increase the force of the current and also decompose water more rapidly, but found this was not the case, and that with an enlarged pile the combustion of metallic wires was more rapid and brilliant, thus proving that the degree of combustion is relative to the surface of the plates (“Encyclopædia Britannica,” 1855, Vol. XXI. p. 626).

The grand experiment made conjointly by Fourcroy, Vauquelin and Seguin on the composition of water from its constituent gases was commenced May 13, 1790, and continued by them without intermission until its completion, nine days later. “The gases were fixed in a close vessel by means of electricity, and produced a nearly equal weight of water” (Trans. Amer. Phil. Soc., N. S., Vol. VI. p. 339, giving description of apparatus for the decomposition and recomposition of water).

Fourcroy was also one of the savants appointed in 1798 by the Academy of Sciences of Paris to examine and report upon the experiments of Galvani. The committee was composed of Guyton de Morveau, Coulomb, Vauquelin, Sabathier, Pelletan, Charles, Fourcroy and Hallé, the last named being charged with the verification of all the then recent discoveries, which were repeated with the assistance of Humboldt, who went to Paris especially for the purpose. The official report fully endorsed the praiseworthy line of researches prosecuted by both Galvani and Humboldt, and the entire series of experiments was at once repeated by many leading physicists throughout Germany.

On June 19, 1803, one of Antoine Fourcroy’s most interesting memoirs, treating of meteoric stones, was read by C. Fourcroy before the French Institute.

References.—Phil. Mag., Vol. XVI. p. 299; Noad’s “Lectures,” pp. 183, 184; Ure, “Dict. of Chem.”; also the interesting biography embracing a list of his very numerous works and treatises, at pp. 846–849, Vol. IX of 1855 “Encyclopædia Britannica.” See likewise, “Royal Society Catalogue of Scientific Papers,” Vol. II. pp. 677–682; Thomas Thomson, “History of Royal Society,” p. 454; Wilkinson’s “Elements of Galvanism ...” 1804, Vol. II. pp. 113, 145, 151, 152, 208, 359; Fahie’s “History of Electric Telegraphy,” p. 194; Izarn, “Manuel du Galv.,” 1804, s. 4, p. 167; “Journal des Savants” for Jan. 1860; P. Sue, aîné, “Hist. du Galvanisme,” Paris, 1802, Vol. II. pp. 159–160, 241, 264. For Louis N. Vauquelin, consult “Cat. Sc. Papers of Roy. Soc.,” Vol. VI. pp. 114–128, 761; also “Mém. des Soc. Savantes et Litt.,” Vol. I. p. 204.

A.D. 1801.—Lehot (C. J.), French physicist, sends a curious and lengthy memoir, regarding the circulation of a very subtile fluid in the galvanic chain, to the Institut National, before which body it is read on the 26 Frimaire, An. IX.

To the analyzation of the above-named memoir, Wilkinson devotes more than half the tenth chapter of his “Elements of Galvanism,” calling attention to a very singular result from numerous experiments which is worthy of special mention. It is the possibility of actually distinguishing one metal from another without seeing or feeling either of them, and he says that by his arrangement of the chain, M. Lehot was able to recognize a portion of zinc from a piece of silver, at the extremity of metallic threads several yards in length.

Lehot’s contributions to the science of animal electricity are too numerous to be given here. Noad summarizes them in the translation from pp. 17, 18 of C. Matteucci’s “Traité des phénomènes ...” Paris, 1844.

He ascertained that in a recently killed animal contractions are excited by the electric current in whatever direction it may be applied, but, when the vitality of the animal has become diminished, if the current is sent in the direction of the ramifications of the nerves, contractions are produced only at the commencement of the current; the reverse takes place when the current is directed contrary to the ramifications of the nerves; i. e. in this case the contractions only take place when the current ceases. After studying the sensation excited by the current on the organs of taste, Lehot concluded that the current which traverses a nerve in the direction of its ramifications excites a sensation when it ceases to pass, though this influence is only exerted at the commencement of its passage when the nerve is traversed in a direction contrary to its ramifications. The later experiments of Carlo Francesco Bellingeri and Stefano Giovanni Marianini entirely confirm those of Lehot.

References.—Annales de Chimie, Vol. XXXVIII. p. 42; Journal de Physique, An. IX, Pluviose, LII. 135; Gilbert, Annalen, IX. 188; P. Sue, aîné, “Hist. du Galvanisme,” Vol. II. pp. 123, 124, 129, 132, 141,142; “Encyclopedia Metropolitana,” Vol. IV (“Electro-Magnetism,” p. 8).

A.D. 1801.—Wollaston (William Hyde), celebrated English chemist and natural philosopher, an associate of Sir Humphry Davy, who had taken the degree of M.D., and joined the Royal Society in 1793, but soon abandoned the practice of medicine to devote himself exclusively to scientific researches, is the first to demonstrate the identity of galvanism and frictional electricity, through a paper read before the above-named society in June 1801.

The latter communication shows that he succeeded in decomposing water as rapidly by means of mere sparks from frictional electricity as through the agency of the voltaic pile, and in a more tranquil and progressive manner than can be assured through shocks from large and powerful apparatus. He concluded that the decomposition must depend upon duly proportioning the strength of the charge to the quantity of water, and that the quantity exposed to its action at the surface of communication depends on the extent of that surface. He observes:

“Having procured a small wire of fine gold, and given to it as fine a point as I could, I inserted it into a capillary glass tube, and after having heated the tube so as to make it adhere to the point and cover it at every part, I gradually ground it down till, with a pocket lens, I could discern that the point of gold was disclosed. I coated several wires in this manner, and found that when sparks from a conductor were made to pass through water by means of a point so guarded, a spark passing to the distance of ⅛ of an inch would decompose water, when the point did not exceed ¹⁄₇₀₀ of an inch in diameter. With another point, which I estimated at ¹⁄₁₅₀₀, a succession of sparks ¹⁄₂₀ of an inch in length afforded a current of small bubbles of air. With a still finer filament of gold, the mere current of electricity, without any perceptible sparks, evolved gas from water.”

In his Bakerian lecture of Nov. 20, 1806, Sir Humphry Davy relates experiments made after the manner contrived by Wollaston, showing that the principle of action is the same in common as in voltaic electricity. Dr. Robert Hare, in a paper read before the Academy of Natural Sciences, “On the Objections to the Theories Severally of Franklin, Dufay and Ampère,” etc., says that, instead of proving the identity of galvanism with frictional electricity, the above-named experiments show that in one characteristic at least there is a discordancy, but that at the same time they possibly “indicate that ethereal may give rise to ethereo-ponderable undulations.” Noad remarks that in these ingenious experiments true electro-chemical decomposition was not effected; that is, “the law which regulates the transference and the final place of the evolved bodies had no influence.” The water was decomposed at both poles independently of each other, and the oxygen and hydrogen gases evolved at the wires are the elements of the water before existing in those places. Faraday observes:

“That the poles, or rather points, have no mutual decomposing dependence, may be shown by substituting a wire or the finger for one of them, a change which does not at all interfere with the other, though it stops all action at the charged pole. This fact may be observed by turning the machine for some time; for though bubbles will rise from the point left unaltered in quantity sufficient to cover entirely the wire used for the other communication, if they could be applied to it, yet not a single bubble will appear on that wire.”

Wollaston communicated a paper to the Royal Society (Phil. Trans., Vol. XCI. p. 427) showing that the oxidation of the metal is the primary cause of the electrical phenomena obtained in the voltaic pile. The oxidating power is finely shown by his eighth experiment, which he thus describes:

“Having coloured a card with a strong infusion of litmus, I passed a current of electric sparks along it, by means of two fine gold points, touching it at the distance of an inch from each other. The effect, as in other cases, depending on the smallness of the quantity of water, was most discernible when the card was nearly dry. In this state a very few turns of the machine were sufficient to occasion a redness at the positive wire, very manifest to the naked eye. The negative wire, being afterward placed on the same spot, soon restored it to its original blue colour.”

He verified in 1802 the laws of double refraction in Iceland spar announced by Huyghens, and wrote a treatise thereon which was read before the Royal Society on the 24th of June, and which contains additional evidence deduced from Dr. Wollaston’s superior mode of investigation.

He is said to have been the first to propose forming the spectrum by using a very narrow pencil of daylight instead of sunlight, and to have first made an accurate examination of the electric light. In his communication to the Philosophical Transactions for 1802 he says:

“When the object viewed is a blue line of electric light, I have found the spectrum to be separated into several images; but the phenomena are somewhat different from the preceding (viz. the spectrum of the blue portion of the flame of a candle). It is, however, needless to describe minutely appearances which vary according to the brilliancy of the light, and which I cannot undertake to explain.”

During the year 1815, Wollaston made a great improvement in the construction of voltaic batteries. Having observed that the power of a battery is much increased with a corresponding economy in zinc plates, when both zinc surfaces are opposed to a surface of copper, he devised what he called an elementary galvanic battery. Each couple of the latter is made up only of a plate of copper doubled up around a zinc plate from which it is kept apart by strips of cork or wood, and the connecting strips of metal are attached to a wooden rod which is lowered or elevated when the battery is in or out of action. He found that a properly mounted plate of zinc, one inch square, was more than sufficient to ignite a wire of platina ¹⁄₃₀₀₀ of an inch in diameter, even when the acid is very diluted (fifty parts of water to one of sulphuric acid).

He was a very careful workman, and in order to adapt his apparatus to the popular uses, he generally endeavoured to construct them upon the most reduced scale (dans des proportions très exigues). He produced platinum wire so extremely fine as to be almost imperceptible to the naked eye. It was estimated that 30,000 pieces of this wire, placed side by side in contact, would not cover more than an inch; that it would take 150 pieces of this wire bound together to form a thread as thick as a filament of raw silk, and that a mile of this wire would not weigh more than a grain. It may be well to add here that the wire made with John Wennstrom’s sapphire plates, for delicate electrical apparatus, is so fine that thirty-six miles of it, properly insulated for Government use in torpedo experiments, measures only about five inches in length by three in diameter when wound upon a spool. The fibre used as carbon filaments in the incandescent lamps is scraped to an even thinness by being drawn through sapphire plates from ³⁰⁄₁₀₀₀ to ⁴⁄₁₀₀₀ of an inch in diameter.

The smallest battery that Wollaston formed of the above-described construction consisted of a thimble without its top, flattened until its opposite sides were about two-tenths of an inch asunder. The bottom part was then nearly one inch wide and the top about three-tenths, and as its length did not exceed nine-tenths of an inch, the plate of zinc to be inserted was less than three-fourths of an inch square (Annals of Philosophy, Vol. VI. p. 210).

We are also indebted to Dr. Wollaston for the first idea of the possibility of producing electro-magnetic rotations. Prof. Schweigger opposed the action of revolving magnetism upon the ground that if it were true, a magnet might be made to revolve around the uniting wire, but Faraday found experimentally not only that a magnet could be made to revolve round the uniting wire, but that a movable uniting wire might be made to revolve around a magnet. (See Faraday’s “Experimental Researches,” Vol, II. pp. 159–162 for “Historical Statement Respecting Electro-magnetic Rotation.”)

Wollaston was made secretary of the Royal Society in 1806, became its president in 1820 after the death of Sir Joseph Banks, and contributed in all thirty-eight memoirs to the Philosophical Transactions of that Institution.

His death occurred Dec. 22, 1828, and during the following February Dr. Fitton, President of the Geological Society, concluded his annual address with the following encomium:

“It would be difficult to name a man who so well combined the qualities of an English gentleman and a philosopher, or whose life better deserves the eulogium given by the first of our orators to one of our most distinguished public characters; for it was marked by a constant wish and endeavour to be useful to mankind.”

References.—Phil. Mag. or Annals, Vol. V. p. 444. See also “The Roll Call of the Royal College of Physicians of London,” by William Munk, M.D., Vol. II; Edin. Phil. Jour., Vol. X. p. 183; Gmelin’s “Chemistry,” Vol. I. p. 424; De la Rive, “Treatise on Electricity,” pp. 444, 445; Phil. Mag., Vol. XXXIII. p. 488; LXIII. p. 15; James Napier, “Manual of Electro-Metallurgy,” 4th Am. ed., pp. 492, 518; Desbordeaux, in Comptes Rendus, Vol. XIX. p. 273; Le Moniteur, No. 40 for 1806; Sue, aîné, “Galvanisme,” Vol. II. pp. 193–195, 199, 202; Joseph Izarn, “Manuel du Galvanisme,” p. 137; Poggendorff, Vol. II. p. 1362; “Encycl. Metrop.,” Vol. IV (Galvanism), pp. 180, 181, 216, 222; Nicholson’s Journal, Vol. V. p. 333; Thos. Young, “Lectures,” London, 1807, Vol. II. p. 679; W. Sturgeon, “Scientific Researches,” Bury, 1850, p. 29; Quarterly Journal of Science for January 1821; British Quarterly Review for August 1846; “Biog. Générale,” Tome XLVI. p. 822; Highton’s “Electric Telegraph,” p. 14; Larousse, “Dict. Universel,” Tome XV. p. 1370; “Cat. Sc. Papers ... Roy. Soc.,” Vol. I. p. 61; Vol. II. pp. 136, 199; “Bibl. Britan.,” 1801, Vol. XVIII. p. 274; 1810, Vol. XLIII. p. 347 (Phil. Mag., June 1809); Vol. I., N.S., 1816, p. 119.

A.D. 1802.—Walker (Adam), English writer and inventor of several very ingenious mathematical instruments, publishes in London his enlarged edition of “A System of Familiar Philosophy,” two volumes, 8vo, in which he devotes ss. 5–9 of Lecture II. vol. i. to magnetism, and all of Lectures VII and VIII of the second volume to electricity.

We are informed, through his preface, that “the identity of fire, light, heat, caloric, phlogiston and electricity, or rather their being but modifications of one and the same principle, as well as their being the grand agents in the order of nature ... are the leading problems of the work.” In another part he tells us:

“If electricity, light and fire be but modifications of one and the same principle ... and they have their origin or foundation in the sun, it is natural to suppose, in issuing from that luminary, they proceed from him first in their purest state, or in the character of electricity; that joining the particles of our atmosphere, electricity becomes light, and uniting with the grosser earth, fire ... that this fire shall be culinary when called forth from the earth by ordinary combustion, and electric when called forth by friction. Thus have I exhibited this wonderful agent in most of the lights in which it has yet been seen; and flatter myself the reader’s deductions from these appearances will be similar to my own, viz. that electricity emanates in a perfect state from the sun and fixed stars; that its particles repel each other and fill all space; that they have an affinity to the earth and planets, but an affinity that cannot easily be gratified, because the surrounding atmospheres are in part non-conductors, being already saturated, and, of course, repellent of the electric fluid” (Lecture VIII. p. 72).

In the section devoted to “Miscellaneous Observations,” he remarks that the magnetic power may almost be said to be created by friction, rather than communicated by it; for a magnet acquires strength by giving magnetism to iron; so that, if all the magnets in the world were lost, magnetism might be revived by rubbing the end of one steel bar against the side of another.

Section V, treating of “Magnetic Attraction,” concludes as follows: “How far these observations and experiments go to establish the doctrine of a magnetic effluvium flowing through the earth, or from one end of a magnet to the other, must be left to the reader’s judgment and opinion. We are apt to laugh at the subtil matter of Descartes and the aether of Euler, as occult qualities, which modern philosophy will not admit into its creed, but this effluvium is a subtil matter, an aether, equally as inexplicable and as equally out of the reach of our five senses to scrutinize; however, if we may venture to guess at causes by effects, and to compare analogies with what we can see, feel, etc., I think we have infinite data in favour of an electro-magnetic fluid, superior to any proof that can be brought of æther being the cause of gravity, light, vision, etc.”

John Read’s letter to the author concerning the electrophorus appears at pp. 47–49 of the second volume (Poggendorff, Vol. II. pp. 1248–1249).

A.D. 1802.—Alexandre (Jean), who is said to have been the natural son of Jean Jacques Rousseau, and to have studied for the medical profession, operates his secret telegraph (télégraphe intime) at Poitiers, and afterwards addresses M. Chaptal, Ministre de l’Intérieur, asking for financial aid in order that he may be enabled to go to Paris and submit his invention to the French Government. This request being refused on account of Alexandre’s unwillingness to divulge his secret, he next obtained an audience of M. Cochon, Prefect of Vienne, before whom he demonstrated his invention so successfully that the latter was induced to make a report of it to M. Chaptal, advising him to invite Alexandre to Paris at the expense of the State. A second refusal, however, followed, and Alexandre went to Tours, where he there also failed to obtain the desired assistance, after giving successful exhibitions of his telegraph before the Prefect of Indre-et-Loire, General Rommereul, as well as before the Mayor and the city officials.

The substance of Prefect Cochon’s communication is to be found translated at pp. 111–113 of Fahie’s “History of Electric Telegraphy,” which latter also contains a full translation of the report addressed, 10 Fructidor, An. X by the celebrated French astronomer, J. B. J. Delambre, to the First Consul, suggesting for the inventor’s representative, M. Beauvais, an interview which Bonaparte, however, refused to grant.

Alexandre died, 1832–1833, without having revealed his secret to any one but M. Beauvais. It is stated by Fahie that in the English Chronicle of June 19–22, 1802, appears a brief account of the above-named exhibition given at Tours, concluding as follows: “The art or mechanism by which this is effected is unknown, but the inventor says that he can extend it to the distance of four or five leagues, even though a river should be interposed.” A copy of the above-named newspaper, doubtless unique, was in Latimer Clark’s library.

References.—“Annales Télégraphiques,” March-April, 1859, pp. 188–199, for M. Edouard Gerspach’s Memoir; “Sci. Am. Suppl.,” No. 384, for a translation of M. Auguste Guéroult’s article in “La Lumière Electrique”; M. Cézanne, “Le Cable Transatlantique,” Paris, 1867, p. 32; M. Bério, “Ephemerides of the Lecture Society,” Genoa, 1872, p. 645.

A.D. 1802.—Sue (Pierre, aîné), a very able French physician, publishes, at Paris, “Histoire du Galvanisme et analyse des différents ouvrages publiés sur cette découverte ...” which is considered by scientists one of the most important works on the subject.

References.—“Biographie Générale,” Vol. XLIV. pp. 618–619; Larousse, “Dictionnaire Universel,” Vol. XIV. p. 1200; Wilkinson, “Elem. of Galv.,” 1804, Vol. I. p. 182.

A.D. 1802.—Brugnatelli (Luigi Valentino), who, after being a pupil, became the close friend and subsequently the colleague of Volta at the Pavia University, is the first to obtain, by means of the voltaic pile, a decidedly practical result in electro-plating. He gilded two large silver medals on bringing them in communication, by means of the steel wire, with the negative pole of a voltaic pile, and by keeping them one after the other immersed in ammoniurets of gold newly prepared and well saturated (Phil. Mag. for 1805).

He also electro-deposited bright metallic silver upon platinum, and observed that when the current entered the liquid by means of a pole of copper or zinc, those metals were dissolved and then deposited upon the negative pole. Spon tells us (“Dictionary of Engineering,” London, 1874, Vol. II. p. 1378) that the solutions employed by Brugnatelli were alkaline; they consisted of ammoniurets of gold, silver or platina, that is, the product obtained by treating the chlorides of gold and platina or the azotate of silver, by ammonia. There is much obscurity in the descriptions of Brugnatelli, but according to the Journal de Physique et Chimie of Van Mons, the most expeditious method of reducing, by means of the battery, dissolved metallic oxides, is to make use of their ammoniurets by placing the ends of two conducting wires of platina into ammoniuret of mercury. The wire of the negative pole speedily becomes covered with small particles of this metal. MM. Barral, Chevalier and Henri tried to reproduce Brugnatelli’s operation by following his descriptions, but with very imperfect results, the nature of the dissolvent employed by the learned Italian not being known.

At p. 136, Vol. XVIII of his Annali di Chimica, etc., Brugnatelli publishes a memoir entitled “Chemical Observations on the Electric Acid.” He says:

“Naturalists have hitherto merely abandoned one erroneous hypothesis for another, in considering the nature of the electric fluid. Some have regarded it as identical with heat; while others have been led to consider it as a modified caloric. The disciples of Stahl ascribed it to the nature of their phlogistic or, at least, supposed it to be a fluid abundantly provided with that principle. Henley conjectured it to be phlogistic, when in a state of repose, and fire, when in a state of activity. Among the moderns, several have been found who have declared it to be an acid; but their opinion has been combated by Gardini, who, by means of several ingenious observations, has endeavoured to demonstrate that it is composed of caloric and hydrogen.”

In the earlier experiments on the decomposition of even chemically pure water by the voltaic column, the presence of an acid was always apparent at the pole evolving oxygen, while alkaline matter appeared at the other (Nicholson’s Journal, quarto, Vol. IV. p. 183).

Mr. William Cruikshanks supposed the former to be the nitrous acid resulting from a combination of the oxygen at the positive pole with the azote of the air held in solution by the water, while the alkali, he said, proceeded from the combination of the same principle with the hydrogen evolved at the negative pole (Nicholson’s Journal, quarto, Vol. IV. p. 261). Mr. C. B. Desormes afterward endeavoured to show that the products were ammonia and muriatic acids (Annales de Chimie, Vol. XXXVII. p. 233). Brugnatelli’s experiments with the couronne de tasses, however, led him to consider it to be an acid sui generis produced by the combination of one of the constituents of water with positive electricity. He classed it as oxi-electric, and of all the metals, gold and platina alone appeared to him not to be sensibly affected by this electric acid.

References.—For Brugnatelli’s record of other experiments and observations and for his Memoirs upon different piles, upon animal electricity, upon the identity of the electric and galvanic fluids, etc. etc., see his “Principes,” etc., 1803, and “Grundsätze des Elektricität,” etc., 1812, his Annali di Chimica, Vols. VII. p. 239; XIX. pp. 77, 153, 274, 277, 280–281; XXI. pp. 3, 143, etc., 239; XXII. pp. 1, etc., 77–92, 257, 301; the Giornale di Chimica, Fis. e Storia Nat. of L. and G. Brugnatelli, G. Brunacci and P. Configliachi, Vol. I. pp. 147–163, 337–353; IX. p. 145; XI. p. 130, and the “Commentarii Medici,” edited by L. Brugnatelli and L. V. Brera; also Brugnatelli’s Giornale Fisico-Medico, etc., and its continuation, Avanzamenti della Medicina e Fisica, the first named containing (Vol. I. p. 280), a repetition of Galvani’s experiments, made by Volta, Rezia and Brugnatelli; G. Bianconi, “Intorno ...” and “Cenni intorno ... Galvanoplastica” (Nuovi Annali della Scienze Naturali); the “Biblioteca Italiana,” of which his son Gaspare Brugnatelli was an editor, in conjunction with Breislak, Configliachi, Carlini, Cotena, Acerbi, Brunacci, Fantonelli, Fumagelli, Ferrario, Giordiani, Gironi and Monti; G. A. Giobert, “Gior. Fis. Med.,” 1188; Du Pré, “Ann. di Chimica,” IX. 156; P. Mascagni, “Lettera ...” for Brugnatelli’s notes; A. Cossa, “Notizie ... elettro-chimica,” 1858; J. Napier, “Man. of El. Met.,” 4th ed., pp. 491, 492; J. B. Van Mons’ Journal de Chimie, Vols. I. pp. 1, 24, 101, 216, 325; II. pp. 106, 216; IV. p. 143; X. p. 114; XVI. p. 132; also Vol. LXXVI; Giornale di Fis. Chim., Vol. I. pp. 4–32, 28, 139–147, 164–166, 338; “Effemeridi Chim. Mediche di Milano,” 1807, Sem. I. p. 57; A. F. Gehlen’s Journal für die Chemie, Vol. I. pp. 54–88; VI. pp. 116–124; VIII. pp. 319–359; L. W. Gilbert, Annalen der Physik, Vols. VIII. pp. 284–299; XVI. pp. 89–94; XXIII. pp. 177–219; Philosophical Magazine, Vols. XXI. p. 187; XXV. pp. 57–66, 130–142; LIII. p. 321; Dr. Thos. Thomson’s Annals of Philosophy, Vol. XII. p. 228; Alfred Smee’s “Elements of Electro-Metallurgy,” History, pp. xxv-xxvi; Journal de Pharmacie, Vol. III. pp. 425, 426; J. Nauche, Journal du Galvanisme, etc., Vol. II. pp. 55–60; P. Sue, aîné, “Histoire du Galvanisme,” An. X, 1802, Vol. I. p. 305; II. pp. 263, 316, 320, 328; Annales de Chimie, Feb. 1818; for Brugnatelli, “Biblioth. Britan.,” Vol. XXXI., 1806, pp. 43, 122, 223 (pile végétale).

A.D. 1802.—Jäger (Karl Christoph Friedrich van), a well-known physicist of Wurtemberg and professor at Stuttgart, confirms by mathematical analysis the theory of electrical distribution and equilibrium, as will be seen by his papers in Gilbert’s Annalen der Physik, Vols. XII. pp. 123, 127; XIII. pp. 399–433; XXIII. pp. 59–84, and LII. pp. 81–108.

The views of Jäger were fully endorsed by Berzelius, who, like Scholz and Reinhold, endeavoured to extend them, and who says that we are indebted to the German physicist for actually the most complete elucidation of the theory of the voltaic pile.

In Vol. XLIX of Gilbert’s Annalen for 1815, pp. 47–66, will be found Jäger’s observations and experiments on Zamboni’s column as well as the papers of Zamboni and Deluc on dry piles. Dr. Thomson says that since Dr. Jäger found that, when the temperature was raised to 104 degrees, or as high as 140 degrees, the pile begins again to act as well as ever, we must conclude from this that dry paper, while cold, is a nonconductor of electricity, but that it becomes again a conductor when heated up to 104 degrees or 140 degrees.

References.—Poggendorff, Vol. I. pp. 1186, 1187; “Catalogue of Scientific Papers of the Royal Society,” Vol. III. p. 525; Jäger on the tourmaline in Gilbert’s Annalen for 1817, Vol. LV. pp. 369, 416, and Jäger, Bohnenberger and Zamboni in the Annalen for 1819, Vol. LXII. pp. 227–246; Figuier, “Expos. et Histoire,” 1857, Vol. IV. p. 433; Davy, “Bakerian Lectures,” 1840, pp. 44–56, on the “Agencies of Electricity.”

A.D. 1802.—Gale (T.), an American physician, publishes at Troy “Electricity or Ethereal Fire ... considered naturally, astronomically and medically, and comprehending both the theory and practice of medical electricity,” etc. Among other things, he describes at pp. 27, 28, various experiments made with his galvanometer; explains at pp. 46–64 how the Newtonian principles are erroneous; and shows at p. 264 how to extract lightning from the clouds; while at pp. 272, etc., are given directions for using electricity both as a sure preventive and cure of diseases.

A.D. 1802.—Gibbes (George Smith), M.D., of Bath, reads before the Royal Society a paper on the Phenomena of Galvanism thus noticed by Dr. Young at pp. 672, 673, Vol. II. of his “Course of Lectures,” London, 1707:

“Dr. Gibbes begins with reciting some experiments on the oxidation produced during the union of tinfoil with mercury, first in the air and then under water. He assumes a different opinion from that of Dr. Wollaston, respecting the origination of electricity in chemical changes, and maintains on the contrary that the electrical changes are to be considered as preceding and favouring the chemical. He imagines that the simple contact of various substances produces changes of electrical equilibrium, and that the action of acids is effectual in promoting these changes, by bringing their surfaces into contact. Dr. Gibbes observes upon Dr. Wollaston’s experiment of immersing zinc and silver in an acid solution, that if they are placed in two separate portions of the fluid, and the parts not immersed are brought into contact there is no emission of gas from the silver; but that it is copiously produced when the contact takes place in the same fluid. He proceeds to relate some experiments which seem to show a difference between galvanism and electricity, particularly that galvanism does not appear to be attracted by metallic points. He also states an experiment in which a piece of paper is placed on tinfoil, and rubbed with elastic gum, and although the tinfoil is not insulated, sparks are produced on raising the paper. Dr. Gibbes concludes with some arguments against the doctrine of the decomposition of water; and advances as a probable opinion, that oxygen and hydrogen gas are composed of water as a basis, united with two other elements, which, combined, form heat.”

As remarked by Wilkinson (“Elements of Galvanism,” London, 1804, Vol. II. pp. 385, 386), Dr. Gibbes’ hypothesis as to the composition of water having been deduced from Richter’s experiments, and these latter proving erroneous, the ingenious superstructure which the doctor has erected must necessarily fall to the ground.

A.D. 1802.—Romagnosi (Gian Domenico Gregorio Giuseppe), Italian jurist of Salsomaggiore, near Piacenza, who had devoted much time to scientific investigation, and was about taking the law professorship at the Parma University, communicates, Aug. 3, 1802, to the Gazetta di Trento, his important paper entitled “Articulo sul Galvanismo.” Of the latter, a translation, made from the reprint at p. 8 of Gilb. Govi’s “Romagnosi e l’Elettro-magnetismo,” appears at pp. 259, 260 of Fahie’s “History of Electric Telegraphy.”

To Romagnosi has by many been given the credit of having discovered the directive influence of the galvanic current upon a magnetic needle. This claim has of late years been again made for him, notably by Dr. Donato Tommasi, of Paris (Cosmos, les Mondes of June 30, 1883), while Dr. J. Hamel endeavoured to prove (pp. 37–39 of “Historical Account ... Galv. and Mag. Elec. ...” reprinted by W. F. Cooke for the Society of Arts, London, 1859) that Oersted was aware of Romagnosi’s experiments at the time he published the discovery of electro-magnetism. This is what Dr. Hamel says:

“I cannot forego stating my belief that Oersted knew of Romagnosi’s discovery announced in 1802, which was eighteen years before the publication of his own observations. It was mentioned in the book of Giovanni Aldini (the nephew of Galvani) ... Oersted was in Paris 1802 and 1803, and it appears from the book of Aldini, that at the time he finished it Oersted was still in communication with him; for he says at the end (p. 376) he had not been able to add the information received from Oersted, Doctor of the University at Copenhagen, about the galvanic labours of scientific men in that country.... It deserves to be remembered, that from Aldini’s book (“Essai théorique et expérimental sur le galvanisme,” etc., Paris, 1804, qto. p. 191, or Vol. I. of the 8vo ed., pp. 339–340) it was known that the chemist, Giuseppe Mojon (Joseph Mojon, in the French), at Genoa, had before 1804 observed in unmagnetized needles exposed to the galvanic current ‘a sort of polarity.’ Joseph Izarn repeats this also in his ‘Manuel du Galvanisme’ (Paris, An. xii., 1804, sec. iii. p. 120, or 1805, sec. ix.), which book was one of those that by order were to be placed in the library of every lycée of France.”