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.”