References.—“Life of Wedgwood,” by Miss Meteyard, 2 vols., 1865–1866; J. D. Reid, “The Telegraph in America,” p. 70.
A.D. 1814.—Singer (George John), distinguished English scientist and writer, publishes the first edition of his valuable “Elements of Electricity and Electro-Chemistry,” of which translations were made, in French by M. Thillaye, Paris, 1817, as well as in German and in Italian during the year 1819.
Mr. Singer is the inventor of the improvement upon Mr. Bennet’s electroscope, which is to be found illustrated and described in nearly all works upon natural philosophy and the main design of which is to diminish, if not totally prevent, the amount of moisture generally precipitated upon the surface of insulators. Mr. Singer remarks that his arrangement so effectually precludes moisture that some of the “electrometers constructed in 1810 and which have never yet (1814) been warmed or wiped, have still apparently the same insulating power as at first.” The use of this apparatus is strongly recommended by Dr. Faraday, whose instructions for the use of electrometers are given at great length at pp. 617–619, Vol. VIII of the eighth “Britannica.”
After describing the above-named electrometer, Mr. William Sturgeon remarks (“Lectures,” London, 1842, pp. 42, 43):
“It is frequently exceedingly difficult, without extensive reading, to confer the merit that is due to invention on the right party, and even then we sometimes err for want of proper information. Mr. Singer has hitherto, with most writers, had the exclusive merit of insulating the axial wire of the electroscope from the brass cap, by a glass tube; and it would appear from the description he gives of this improvement in his excellent treatise on electricity that he was not aware of anything of the kind being previously done. It appears, however, by an article of Mr. Erman in the Journal de Physique, Vol. LIX. p. 98, and Nicholson’s Journal, Vol. X, published in 1805, that a Mr. Weiss had applied the glass tube for the purpose of insulating the axial wire of Bennet’s electroscope. The account runs thus: ‘The electrometer he (Mr. Erman) used was that distinguished in Germany as the electrometer of Weiss.’ From this it would appear to have been long known. ‘The length of its leaves of gold is half an inch, and the diameter of the glass cylinder which encloses them is three-quarters of an inch, the height being an inch and a half. Its cover of ivory does not project above the glass, and is perforated in the middle with a hole in which a smaller glass tube is fixed, and through this last tube passes the metallic rod that serves to suspend the gold leaves.’ Singer’s improvement, first published in 1814, would, therefore, consist in adding the brass ferrule, which covers the glass tube first introduced by Weiss.”
Singer is also the inventor of one of the best-known amalgams for the cushions of the electric machine. It is described at p. 536, Vol. VIII of the eighth “Britannica,” where it is said that a mixture of one part tin and two parts mercury is very effective, as is also the amalgam consisting of mosaic gold and the deutosulphuret of tin. (Other descriptions of the application of mosaic gold on the rubber are to be found at p. 432, Vol. II of “Young’s Course of Lectures”; Woulfe, Phil. Trans., 1771, p. 114; Bienvenu and Witry de Abt, Lichtenb. Mag., Vols. II. p. 211, and IV. st. 3, pp. 58–61; Marquis de Bouillon, “Observ. de Physique,” XXI.)
The dry electric columns which Mr. Singer invented are alluded to in Phil. Mag., Vols. XLI. p. 393 and XLV. p. 359, while the results of his experiments on the electric fusion of metallic wires and the oxidation of metals, as well as those made upon the electricity of sifted powders and also in order to ascertain the effects of electricity upon gases, are to be found recorded at pp. 564, 592, 593 and 597, Vol. VIII of the 1855 “Britannica,” and at p. 46 (“Electricity”) of “Library of Useful Knowledge.”
References.—pp. 15, 16 of the last-named work; Poggendorff, Vol. II. pp. 938, 939; Figuier, “Exp. et Hist.,” 1857, Vol. IV. p. 267; Sturgeon’s “Lectures,” 1842, p. 11; Phil. Mag., Vols. XXXVII. p. 80; XLII. pp. 36, 261; XLIII. p. 20; XLVI. pp. 161, 259; likewise Ch. Samuel Weiss, at Poggendorff, Vol. II. pp. 1287–1289; “Bibl. Britan.,” Vol. XLIII, 1810, p. 166; Vol. XLVII, 1811, pp. 3, 113, 213, 313; Vol. LVI, 1814, pp. 197, 318.
A.D. 1814–1815.—Fraunhofer—Frauenhofer (Joseph von), a practical Bavarian physicist and optician, who had been assistant to the celebrated George Reichenbach, publishes his observations on spectra in a pamphlet entitled “Bestimmung des Brechungs und Farbenzerstreuungs-Vermögens ...”
In the latter work will be found detailed his experiments with the electric spark, which he found to give a different spectrum from all other lights. Sir David Brewster says that in order to obtain a continuous line of electrical light Fraunhofer brought to within half an inch of each other two conductors, and united them by a very fine glass thread. One of the conductors was connected with an electrical machine and the other communicated with the ground. In this manner the light appeared to pass continuously along the fibre of glass, which consequently formed a fine and brilliant line of light. When this luminous line was expanded by refraction, Fraunhofer saw that, in relation to the lines of its spectrum, electric light was very different both from the light of the sun and from that of a lamp. In this spectrum he met with several lines partly very clear, and one of which, in the green space, seemed very brilliant compared with other parts of the spectrum (Edin. Jour. of Sci., No. XV. p. 7). He saw in the orange another line not quite so bright, which appeared to be of the same colour as that in lamplight spectra; but in measuring its angle of refraction he found that its light was much more strongly refracted, and nearly as much as the yellow rays of lamplight. In the red rays toward the extremity of the spectrum, he observed a line of very little brightness, and yet its light had the same degree of refrangibility as the clear line of lamplight, while in the rest of the spectrum he saw the other four lines sufficiently bright. In a subsequent paper read at Munich in 1823 (“Neue Modifikation des Lichtes ...” or “New Modification of Light”) and in Schumacher’s “Astronomische Abhandlungen,” Fraunhofer states that, by means of the large electrical machine in the cabinet of the Academy of Munich, he obtained a spectrum of electric light in which he recognized a great number of light lines, and that he had determined the relative place of the lightest lines as well as the ratios of their intensities.