A.D. 1845. 1845. 1845. 1845. 1846. 1846. 1846. (See M. HEIDER, in 1845, employed a platinum wire, heated by a voltaic battery, to cauterize the dental nerves. De la Rive's Treatise on Electricity, Vol. III., p. 687.) Professor WILLIAM THOMSON, in 1845, showed how the electric polarization is to be taken into account in the Leyden jar. (See Encyclopædia Britannica, 8th edition, art. Electricity, p. 534.) Mr. C. V. WALKER, in 1845, by means of three Daniell's cells and a brass anode, electro-deposited brass from a strong solution of cyanide of potassium which had been sequentially electrolysed with a copper and zinc anode. Alloys of gold and copper, or gold and silver, may be electro-deposited by similar means. (See British Association Report for the meeting in 1845, p. 30.) Dr. REMAK, in 1845, discovered that certain points favourable for the application of electricity to the human body "corresponded with the points of entrance of the "muscular nerves, and that the degree of contraction of a "muscle was proportioned exactly to the number of motory nerve-fibres embraced by the current at its point "of application." (See Dr. Remak's Ueber Methodische Electrisirung gelähmter Muskeln, Berlin, 1845; also The British and Foreign Medico-Chirurgical Review, January 1859, p. 91, et seq.) Dr. PRING, in 1846, submitted to the Royal Society his process of electro-disruptive etching. The hardest steel is thereby engraved by the disruptive discharges passing between a metal tool and the face of the plate. A galvanic series, in connection with an electro-magnetic coil, is used, the plate being attached to one pole and the tool to the other pole of the arrangement. (See Smee's Electrometallurgy, pp. 337, 338.) M. CRUSELL, of St. Petersburgh, in 1846, "conceived "the idea of cutting and cauterizing the tissues, by means "of a wire or a thin plate of platinum, rendered incan"descent by a powerful electric current, by making them "act after the fashion of a saw, by means of a backward "and forward motion." (See De la Rive's Treatise on Electricity, Vol. III., p. 687.) Mr. HEARDER, in 1846, constructed his electro-dynamic coil. By means of this apparatus, in connection with a A.D. 1847. 1847. 1847. 1847. 1847, galvanic battery and the condenser of M. FIZEAU, sparks can be obtained through an intervening space of air without previous contact. (See Noad's Manual of Electricity, pp. 727, 728.) Professor WILLIAM THOMSON, in 1847, advanced his singularly beautiful theory of electrical images and reflections. (See Encyclopædia Britannica, 8th edition, art. Electricity, p. 534.) Professor SILLIMAN, about the year 1847, successfully copied the iridescent colors of mother-of-pearl by the electrotype process. For this purpose a mould is taken of the shell in fusible metal, and an electro-cast from that mould. (See Smee's Electro-metallurgy, pp. 281, 282; also Timb's Year Book of Facts, 1847.) WERNER SIEMENS, in the summer of 1847, tried successfully a gutta-percha-covered copper wire on an electric telegraph line of from four to five English miles in length, viz., between Berlin and Gross-Beeren. (See Journal of the Society of Arts, April 23, 1858, p. 350.) Mr. E. LOOMIS, in a letter to Mr. Sabine, dated August 2, 1847, proposes to use Morse's "magnetic telegraph," to determine the difference of longitude between Philadelphia and Washington. (See Abbé Moigno's Traité de Télégraphie Electrique, pp. 124-126.) CHARLES V. WALKER, F.R.S., in 1847 and 1848, pro1848. posed and adopted underground wire insulated with gutta percha for electric telegraphs. (See Whitehouse's pamphlet, The Atlantic Telegraph, p. 4.) 1848. M. FOUCAULT, in 1848, constructed an electric light apparatus, in which the luminous point remains fixed; to effect this the carbons are moved by clock-work, which is liberated, by the armature of an electro-magnet included in the electric circuit, on the weakening of the electric current. M. BRETON'S apparatus is similar to M. Foucault's, but instead of springs for approximating the carbons, weights and counterpoises are used; there is also a ratchet wheel and click movement instead of a detent employed to maintain the separation of the electrodes. In DUBOSCQ's apparatus the electrodes have a constant tendency to come into contact, the upper one by its weight, the lower by a A.D. spiral spring tending to unwind an endless screw; during the passage of the current the regulating electro-magnet's lever armature gears into the endless screw and prevents the approach of the electrodes by intervening mechanism, but on the weakening of the current the force of the spring preponderates, moves the lower electrode, and revolves a barrel carrying a cord connected with the upper electrode; a pulley of variable diameter, which transmits motion to the barrel, enables the comparative motion of the electrodes to be accurately adjusted, the luminous point thus remains fixed under all circumstances. (See De la Rive's Treatise on Electricity, Vol. II., pp. 326-328, also Vol. III., pp. 310-315.) 66 1848. Dr. FARADAY, in 1848, showed that gutta percha has powerful insulating properties. "When rubbed it shows negative electricity." (See London and Edinburgh Philosophical Magazine and Journal of Science, Vol. XXXII., p. 165; also Gmelin's Handbook of Chemistry, Vol. I., p. 313.) 1848. WERNER SIEMENS, in 1848, in the bay of Kiel, and in crossing the Rhine at Cologne and other rivers, successfully established subaqucous electric telegraph conductors. (See Journal of the Society of Arts, April 23, 1858, p. 351.) 1848, M. DUBOIS REYMOND, in 1848-9, published his re1849. searches in animal electricity. (See British and Foreign Medico-Chirurgical Review, January 1854, p. 126.) 1849. 1849. 1849. CHARLES V. WALKER, F.R.S., on January 10, 1849, made an experiment of submerging a gutta-percha-covered electric conductor in the open sea. 66 He attached two miles "of insulated wire, submerged in the sea, to the end of one "of the wires of the South Eastern Company's" [telegraphic?]" system at Folkestone, and spoke through it "to the Directors in London from the deck of the "steamer." (See Whitehouse's pamphlet, The Atlantic Telegraph, p. 4.) WERNER SIEMENS, in 1849, observed the electric charge in underground telegraphic line wires. (See Journal of the Society of Arts, April 23, 1858, p. 359.) BAUMGARTNER, in 1849, made observations which proved the existence of earth currents in telegraphic wires. (See Noad's Manual of Electricity, p. 239.) A.D. 1849. 1850. 1850. 1850. 1851. Mr. W. H. WALENN, in 1849, invented a single-fluid constant galvanic battery composed of cast-iron, acid sulphate of iron, and prepared zinc. The zinc plate is coated with lead (from a solution of the acetate), and then amalgamated; or it may be immersed in a solution containing lead and mercury. (See British Association Report for the meeting in 1849, pp. 45, 46.) Messrs. BRETT, in January 1850, "projected and obtained "concessions" for an electric telegraph line across the Channel. (See Whitehouse's pamphlet The Atlantic Telegraph, p. 4.) M. FROMENT's electric telegraph was invented in 1850. This apparatus writes or marks the dispatch in conventional signs, by means of a style which cuts as it writes, because it turns round itself in the same time that it makes its to-and. fro movement. The style is moved in a direct manner by the armature of the electro-magnet, and can make from 3000 to 4000 vibrations per minute (See Abbé Moigno's Traité de Télégraphie Electrique, p. 104.) Professor PAGE of America, in 1850, described his electro-magnetic engine in a series of lectures which he delivered before the Smithsonian Institution. This arrangement consisted of electro-dynamic helices, which, by their alternate excitement, gave reciprocating motion to iron cores; a connecting rod and crank communicated this motion to a fly-wheel shaft, and thence to the work to be performed. (See Dodd's Industrial Applications of Electricity, p. 10; also De la Rive's Treatise on Electricity, Vol. III., pp. 339, 340.) RUHMKORFF, in 1851, constructed his electro-dynamic coil. GROVE and GASSIOT subsequently made researches upon the passage of the electric spark developed by this apparatus in connection with Fizeau's condenser, and made to traverse various media. POGGENDORFF and FOUCAULT Constructed improved instruments of this kind. (See Noad's Manual of Electricity, pp. 726-730; also De la Rive's Treatise on Electricity, Vol. II., pp. 23, 24, and Vol. III., pp. 722-729; also Poggendorff's Annalen, t. xciv., p. 289; also Annales de Chimie et de Physique, t. xliv., p. 375; also Comptes Rendus de l'Académie des A.D. Sciences, t. xlii., p. 215; also Arch. des Sc. Phys. et Nat., t. xxxi. of the 4th series, p. 243; also Comptes Rendus de l'Académie des Sciences, t. xliii., p. 44.) Messrs. G. P. and R. F. BOND of the Cambridge, U.S., 1851. Observatory, in 1851, read an account of their apparatus for making astronomical observations by means of electromagnetism to the British Association at Ipswich. This apparatus consists of an electric break-circuit clock, a galvanic battery, and a spring governor, by which uniform motion is given to the paper. The cylinder revolves once per minute, and the observer depresses a break-circuit key at the instant of the transit of a star over the wire or hair line of the telescope, thus making a record accordingly on the paper. This apparatus enables observations to be increased in number, and reduces the personal equation to the minimum. (See British Association Report for the meeting in 1851, pp. 21, 22.) 1851. 1852. 1853. Messrs. BRETT, on September 25, 1851, laid an electric telegraph cable of massive construction across the Channel. (See Whitehouse's pamphlet The Atlantic Telegraph, p. 4.) Mr. LATIMER CLARK, in April 1852. noticed the phenomenon of the slow transmission of electric currents through submerged wires. (See Journal of the Society of Arts, April 23, 1858, p. 356.) M. BOULU, from the year 1853, endeavoured to reduce tumours by causing electric excitation to penetrate into the substance itself of the tumours. (See De la Rive's Treatise on Electricity, Vol. III., pp. 683, 684.) Dr. FARADAY communicated the results of his enquiries, respecting the Leyden jar charge of buried electric conducting wires, to the members of the Royal Institution, on 1854. January 20, 1854; he then showed that the electric currents which he employed travelled at the rate of only 750 miles per second along buried wires. (See Whitehouse's pamphlet The Atlantic Telegraph, p. 5.) 1854. 1854. Mr. WHITEHOUSE, in 1854, commenced his researches on the possibility of working an Atlantic electric telegraph. (See Whitehouse's pamphlet The Atlantic Telegraph, p. 6.) Mr. RUTTER, in 1854, invented a very delicate electroscope, that rendered the development of human electricity |