The description of Dr. Hare’s electrical machine (before alluded to at Van Marum A.D. 1785), wherein the plate is mounted horizontally so as to show both negative and positive electricity, was published in London during 1823, and can be found in Vol. LXII of the Phil. Mag., as well as at pp. 538, 604, 605, Vol. VIII of the 1855 “Encycl. Brit.” In the last-named article mention is made of the introduction of a band (illustrated Fig. 7, Plate CCXXII) which prevents the plate from being cracked, as it frequently is, through some hasty effort to put it in motion while it adheres to the cushions. It is also therein stated that in order to offset the heavy expense attending the breakage of large cylinders and plates, M. Walkiers de St. Amand, of Brussels, among many others, made an apparatus of varnished silk 25 feet long and 5 feet wide, capable of giving sparks 15 inches long (see A.D. 1785), while Dr. Ingen-housz constructed machines with pasteboard discs four feet in diameter, soaked in copal or amber varnish dissolved in linseed oil, which gave sparks of one and even two feet in length.
In the fifth volume, new series, of the Amer. Phil. Trans. will be found Dr. Hare’s “Description of an Electrical Machine,” with a plate four feet in diameter, so constructed as to be above the operator; also of a battery discharger employed therewith, and some observations on the causes of the diversity in the length of the sparks erroneously distinguished by the terms positive and negative. Hare is also the inventor of a single gold-leaf electroscope of such great delicacy that it has, he says, enabled him to detect the electricity produced by one contact between a zinc and copper disc, each six inches in diameter (Noad, “Manual,” p. 29; Harris’ “Rudim. Elect.,” p. 50; Silliman’s Journal, Vol. XXXV). He invented several other electrical appliances, and he is likewise the author of numerous important memoirs which it would be impossible to detail in the narrow limits of this “Bibliographical History.” They will, however, be found recorded in the publications named below.
References.—Phil. Trans. for 1769, Vol. LXIX. p. 659. See also, for Walkiers de St. Amand, the entry at A.D. 1785, as well as Lichtenberg’s Magazin, Vol. III, 1st, p. 118, for the last-named year. To these might be added the machines made by Mundt, of silken strips (Gren’s Journal der Physik., Vol. VII. p. 319); by N. Rouland, “Descript. des mach, elec. à taffetas,” Amsterdam, 1785; by Croissant and Thore; of paper by W. H. Barlow (Phil. Mag., Vol. XXXVII. p. 428), of gutta percha; as well as machines of rubber by Fabre and Kunneman, as shown at Th. Du Moncel’s “Exposé des appl. de l’El.,” second ed., p. 399, and third ed., 1872, Vol. II. pp. 78, 122, 265, besides the peculiarly constructed machines of Erdmann Wolfram (Ferussac, “Bulletin des Sciences Tech.” for 1824); of G. H. Seiferheld, “Beschreib ... elektrische mach,” 1787; of F. E. Neuman, as modified by F. Zantedeschi (“Ann. Sci. Lom.-Ven.,” XII. p. 73), and of those described at p. 420, Vol. II, and at p. 4, Vol. III of Nicholson’s Magazine. Consult likewise, pp. 335, 340, second Am. ed. of the “New Edin. Encycl.,” 1817. Poggendorff, Vol. I. pp. 1018, 1019; “Cat. Sci. Papers of Roy. Soc.,” Vol. III. pp. 177–182; Vol. VI. p. 182; Silliman’s Am. Jour. Sci. and Arts, Vols. II. pp. 312, 326; III. p. 105; IV. p. 201; V. p. 94; VII. pp. 103, 108, 351; VIII. pp. 99, 145; X. p. 67; XII. p. 36; XIII. p. 322; XV. p. 271; XXIV. p. 253, XXV. p. 136; XXXI. p. 275; XXXII. pp. 272, 275–278, 280–285; XXXIII. p. 241; XXXV. p. 329; XXXVII. pp. 269, 383; XXXVIII. pp. 1, 336, 339; XXXIX. p. 108; XL. pp. 48, 303; XLI. p. 1, and XLIII. p. 291; Phil. Mag., Vols. LVII. p. 284; LXII. pp. 3, 8, etc.; Phil. Mag. or Annals, Vol. VI. pp. 114, 171; Journal of the Franklin Institute, third series. Vol. XV. pp. 188, etc.; Trans. of the Am. Phil. Soc., N.S., Vol. VI. p. 297 (for Hare and Allen) also pp. 339, 341, 343, and Vol. VII for 1841; “Mem. Jos. Henry,” Washington, 1880, p. 82; Figuier, “Exp. et Hist.,” 1857, Vol. IV. pp. 391, 401, 402; Dr. Thomas Thomson, “Outline of the Sc.,” London, 1830, pp. 515, 517; Appleton’s “New Amer. Cycl.,” Vol. VII. p. 66; Appleton’s “Dict. of Machines, Mechanics ...” 1861, pp. 432, 433; Dr. William Henry, “Elem. of Exper. Chem.,” London, 1823, Vol. I. p. 169, and Supplement, Chap. VII. p. 29; “Annual of Sc. Disc.” for 1862, p. 99.
A.D. 1819.—Gmelin (Leopold), the most distinguished member of the family of that name, publishes, at Frankfort, 1817–1819, the first edition of his celebrated “Handbuch d. theoret. Chemie,” which embodies the whole extent of chemical science as it then existed and the fourth and last edition of which, under the author’s supervision, appeared during 1843–1845. This extensive work is well known, both in its original form and through the very able translation of it made by Mr. Henry Watts. In the report of the Council of the Chemical Society for 1854, it is said that “the greatest service which Gmelin rendered to science—a service in which he surpassed all his predecessors and all his contemporaries—consists in this: that he collected and arranged in order all the facts that have been discovered in connection with chemistry. His Handbuch der theoret Chemie stands alone. Other writers on chemistry have indeed arranged large quantities of materials in systematic order, but for completeness and fidelity of collation and consecutiveness of arrangement, Gmelin’s Handbuch is unrivalled.”
Although many references have been made herein to Leopold Gmelin’s treatment of such departments of science as directly appeal to the readers of this compilation, it is well to mention some of the headings under which they are to be found. They are, “Electricity,” “Electro-chemical Theories,” “Electrolysis,” “Technical Apparatus of Electricity,” “Theory of Galvanism,” “Galvanic Batteries,” “Magnetic Condition of All Matter,” etc., etc., the whole occupying pp. 304 to 519, Vol. I of Gmelin’s English edition. The list of many of Leopold Gmelin’s valuable contributions to science is given in the “Catalogue Sc. Papers Roy. Soc.,” besides which may be mentioned his “Uber e angebl. meteorische masse” (Gilbert, Annalen, LXXIII for 1823), and his “Versuch einer elektro-chemisch. theorie” (Poggendorff’s Annalen der Physik und Chemie, Vol. XLIV for 1838, while at pp. 547–550 of Mr. J. J. Griffin’s able work, published in London during 1858, will be found the results obtained by Prof. G. Magnus and by Prof. Faraday with a summary of Gmelin’s conclusions under the heading of “The Evidence of Electrolysis in Favour of the Radical Theory.”
Gmelin Family
This family, which, through four generations, has been continuously distinguished for its valuable contributions to chemistry as well as to the natural and medical sciences, deserves equally well here of such a special mention as was accorded to the Bernoulli and Cassini families, under dates A.D. 1700 and 1782–1791.
Johann Georg Gmelin (1674–1728), a very able chemist and pharmaceutist of Tübingen, was the father of:
Johann Conrad Gmelin (1707–1759), physician and author in the same city of Tübingen.
Johann Georg Gmelin (1709–1755), distinguished naturalist and chemist, who graduated as M.D. in his nineteenth year, became a member of the St. Petersburg Acad. of Sc. and was sent by the Empress Anna, in company with G. A. Müller and other noted scientists, upon a ten years’ exploring expedition through Siberia. He was one of the first explorers of Northern Asia, and a genus of Asiatic plants was named Gmelina after him by Linnæus.