References.—Nicholson’s Journal, Vol. XV. pp. 50–52; Vol. XXIII. pp. 258–260; Gehlen’s Journal, Vol. II, 1806, pp. 155–158. For his other papers, consult Nicholson’s Journal, Vol. IX. p. 179; Vol. X. pp. 166–167; Vol. XIX. pp. 156–157; Vol. XXVI. pp. 72–75; Gilbert’s Annalen, Vol. XXIII. pp. 441–447; “Roy. Soc. Catal. of Sc. Papers,” Vol. V. pp. 900–901; Sturgeon’s Scientific Researches, Bury, 1850, p. 153; Sir Humphry Davy’s lecture “On some chemical agencies of electricity,” read Nov. 20, 1806; Annales de Chimie, Vol. LX. p. 314; Vol. LXI. pp. 330–331; “Bibl. Britan.,” Vol. XXXIII, 1806, p. 324.
A.D. 1806.—Maréchaux (Peter Ludwig), correspondent of the French Galvani Society at Wesel, is the first to construct an effective dry pile containing paper discs. He makes known through M. Riffault (Annales de Chimie, Vol. LVII for January 1806, p. 61), that water is not essential to the production of galvanic effects, and his experiments are repeated for the Chemical Society by M. Veau Delaunay, as shown in Journal de Physique, Messidor, An. XIV.
This “Maréchausian Pile,” or colonne pendule, as it was originally denominated, consists of pairs of oven-dried cardboard, pasteboard, or blotting-paper, and of copper discs all pierced in such manner as to be suspended by three silken cords which hold them fast in position. Sturgeon remarks (“Researches,” pp. 199 and 239) that in this dry column the electric pulsations are, in consequence of the very great number of interrupting papers, less frequent than in either the processes of Volta or in that of Seebeck, notwithstanding which the instrument produces slow pulsatory currents.
References.—W. Sturgeon’s “Annals of Electricity,” Vol. I. p. 256, note; Vol. VIII. pp. 379, 484; Phil. Mag., Vol. XXIV. p. 183; Poggendorff, Vol. II. p. 46; “Roy. Soc. Cat. of Sci. Papers,” Vol. IV. p. 236; Gilbert’s Annalen der Physik, Vols. X.-XXVII passim, also Vol. XV. p. 98 and Vol. XVI. p. 115 giving a description of the Maréchaux electro-micrometer (screw and silver leaf), likewise Vol. XXII, containing an account of the observations made by M. Paul Erman.
A.D. 1807.—Young (Thomas), M.D., a very celebrated English scientist, “eminent alike in almost every department of human learning,” who was the associate of Davy at the Royal Institution, and who became the successor of Volta as Foreign Associate of the French Academy of Sciences, publishes his very elaborate “Course of Lectures on Natural Philosophy and the Mechanical Arts,” upon which he was assiduously engaged for five years, and a new edition of which was issued (with additional references and notes) by the Rev. P. Kelland, M.A., F.R.S., during the year 1845.
The above-named work comprises the sixty lectures which Dr. Young delivered during his connection with the Royal Institution and includes also his optical and other memoirs, as well as a very extended classified catalogue of publications in every leading department of science. His biographer in the “English Encyclopædia” remarks that Young’s lectures embody a complete system of natural and mechanical philosophy, drawn from original sources, and are distinguished not only by extent of learning and accuracy of statement, but by the beauty and originality of the theoretical principles. One of these is the principle of interferences in the undulatory theory of light. “This discovery alone,” says Sir John Herschel, “would have sufficed to have placed its author in the highest rank of scientific immortality, were even his other almost innumerable claims to such a distinction disregarded.” The first reception, however, of Dr. Young’s investigations of light was very unfavourable. The novel theory of undulation especially was attacked in the Edinburgh Review, and Dr. Young wrote a pamphlet in reply, of which it is said but one copy was sold, but it is now generally received in place of the molecular or emanatory theory.
His review and treatment of the field of electrical and magnetic phenomena, as may be imagined from the foregoing, is very extensive, and as no justice could be done it by making therefrom such extracts as would suitably come within the scope of the present “Bibliographical History,” only an extract from the lecture treating of “Aqueous and Igneous Meteors” will here be given.
Speaking of the aurora borealis, he says “that it is doubtful if its light may not be of an electrical nature. The phenomenon is certainly connected with the general cause of magnetism. The primitive beams of light are supposed to be at an elevation of at least 50 or 100 miles above the earth, and everywhere in a direction parallel to that of the dipping needle; but perhaps, although the substance is magnetical, the illumination, which renders it visible, may still be derived from the passage of electricity, at too great a distance to be discovered by any other test.... It is certainly in some measure a magnetical phenomenon; and if iron were the only substance capable of exhibiting magnetic effects, it would follow that some ferruginous particles must exist in the upper regions of the atmosphere. The light usually attending this magnetical meteor may possibly be derived from electricity, which may be the immediate cause of a change in the distribution of the magnetic fluid contained in the ferruginous vapours that are imagined to float in the air.”
The assumption of ferruginous particles or vapours, remarks Prof. Robert Jameson, of the Edinburgh University, seems, however, purely gratuitous and imaginary; and as iron is not the only substance or matter capable of exhibiting magnetic effects, light itself being susceptible of polarization, the above hypothesis is, therefore, untenable even on the ground upon which it has been rested by its author. But it is, nevertheless, certain that the cause of this luminous meteor is intimately connected with magnetism and electricity; or, rather, as the magnetic is variously modified and effected by the electric power, with the phenomena of electro-magnetism.
References.—Young’s Catalogue for “Aurora Borealis” and “Terrestrial Magnetism” (“Lectures,” London, 1807, Vol. II. pp. 440–443, 488–490), “Journal Roy. Inst.,” Vol. I; Dr. George Peacock’s “Life of Thomas Young”; also “Miscellaneous Works of T. Young,” London, 1855; “Memoirs of the Life of Thos. Young,” London, 1831; also Vol. XIII of John Leitch’s “Hieroglyphical Essays and Correspondence,” all of which contain every contribution made by the scientist to the Phil. Trans., as well as many other important articles communicated by him to other scientific publications of his time; “Eloge Historique de Dr. Thomas Young,” par M. Arago, in Mém. de l’Acad. Roy. des Sc., etc., Tome XIII. p. 57; Quarterly Review for April 1814; Tyndall, “Heat as a Mode of Motion,” 1873, pp. 267, 268; Annales de Chimie, Feb. 1815; Whewell, “History of the Inductive Sciences,” 1859, Vol. II. pp. 92, 96, 106, 111–118.