Aurora Borealis, or Northern Polar Light
Dr. Halley was the first to give (Phil. Trans., No. 347) a distinct history of this phenomenon, which has certainly an electric as well as magnetic origin, and to which Gassendi originally gave the name it now bears, as has been stated at A.D. 1632.
According to Dr. Lardner (“Lectures,” Vol. I. p. 137), Prof. Eberhart, of Halle, and Paul Frisi, of Pisa, first proposed an explanation of the aurora founded upon the following: 1. Electricity transmitted through rarefied air exhibits a luminous appearance, precisely similar to that of the aurora borealis. 2. The strata of atmospheric air become rarefied as their altitude above the surface of the earth is increased, a theory which has since been countenanced by many scientists. It has been observed, notably by Dalton, of Manchester, that the primitive beams of the aurora are constantly in a direction parallel to that of the dipping needle, and that the latter appears most affected when the aurora is the brightest. Arago noticed that the changes of inclination amounted, upon one occasion to 7’ or 8’. The discovery that the magnetic needle was agitated during the presence of an aurora has been ascribed to Wargentin (Am. Journal Sc., Vol. XXX. p. 227), though it is claimed by the friends of Olav Hiörter (see A.D. 1740), that it was independently ascertained by the latter during the year 1741.
The well-known Swiss chemist Auguste Arthur De la Rive has made many important observations upon the electric character of the aurora, the experiments carried on by him in the mountains of Finland being thus described: “We surrounded the peak of a mountain with copper wire, pointed at intervals with tin nibs. We next charged the wire with electricity, and nearly every night during our stay produced a yellowish white light on the tin points, in which the spectroscope analysis revealed the greenish yellow rays so characteristic of the aurora borealis. On the peak of Pietarintumturi we were especially successful, an auroral ray making its appearance directly over and about 150 yards above the copper coil.”
A complete list of all auroras appearing prior to 1754 is to be found in Jean Jacques d’Ortons de Mairan’s, Paris, 1731, “Traité Physique de l’Aurore Boréale,” and a catalogue of auroræ observed, 1800–1877, has been made up by M. Zenger (Sci. Am. Supp., p. 10915). One of the most interesting displays is known as the purple aurora, alluded to in the Annals of Clan-mac-noise as having appeared A.D. 688 (Biot “Note sur la direction,” etc., Comptes Rendus, Tome XIX for 1844, p. 822). Between September 19, 1838, and April 8, 1839, Lottin, Bravais, Lilliehöök and Siljeström observed 160 auroras at Bossekop (69° 58’ N. lat.) in Finmark and at Jupvig (70° 6’ N. lat.); they were most frequent during the period the sun remained below the horizon, that is, from November 17 to January 25. During this night of 70 times 24 hours there were 64 auroras visible (Comptes Rendus, Tome X. p. 289; Martin, “Météorologie,” 1843, p. 453; Argelander, in the “Vorträgen geh. in der Königsberg Gesellschaft,” Bd. I. s. 259).
A Finnish physicist, named S. Lenström, who had been attached to the Nordenskjold Polar Expedition of 1868, visited Lapland in 1871, and, after a series of important observations, constructed an apparatus that permitted him to “artificially reproduce the light of the aurora.” The intensity of this light is so great at times that Lowenörn perceived the coruscations in bright sunshine on the 29th of January, 1786, and Parry saw the aurora throughout the day during the voyage of 1821–1823.
The height of the aurora has been variously estimated, but it is seldom found to be less than forty-five miles above the surface of the earth. Father Boscovich estimated at 825 miles the height of the one observed by the Marquis of Poleni on the 16th of December, 1737. The extent of the aurora, according to Dalton, has been known to cover an area of 7000 or 8000 square miles.
References.—“Mem. de Turin,” An. 1784–5, Vol. I. part ii. pp. 328, 338; Young, “Lectures,” Vol. I. pp. 687, 716; Herschel, “Prelim. Discourse,” pp. 93, 329, 330; Phil. Trans., 1753, p. 350; Müller’s “Kosmischen Physik”; Noad, “Manual,” pp. 225–237; also all the references at pp. 187–196, Vol. I of Humboldt’s “Cosmos,” Bohn, London, 1849, as well as in Ronalds’ “Catalogue,” pp. 23–24; Mairan, at Vol. X. p. 961, “Dict. Univ.,” and Vol. XXVI. p. 161, of the “Biog. Universelle”; Trans. Cambridge Phil. Soc., Vol. I; “Isis Unveiled,” Vol. I. pp. 417, 418.
See likewise the “Pharsalia” of Marcus Annæus Lucanus, translated by J. Krais, I. pp. 518–527; Plutarchus, “De facie in orbe lunæ,” cap. 26; the “Annals” of Caius Cornelius Tacitus, Germania, XLV. 1st ed., Venice, 1470; “Das Polarlicht,” H. Fritz, Leipzig, 1881, pp. 4–6, 332; Mairan’s “Traité Physique,” etc., 1731, pp. 179–181; Grégoire du Tour, Lumière Electrique, 1882, Vol. VII. p. 389; Elias Loomis, “The Aurora Borealis,” etc., p. 220 of the Reports of Smiths. Inst., 1865; A. M. Mayer, “Observations,” etc., Amer. Jour. of Sc., February 1871; “A copy of the Catalogue of Aurorae Boreales observed in Norway from the earliest times to June 1878” (“Nature,” December 4, 1902, p. 112); “La cause de l’aurore boréale,” Claudius Arrhenius, in the Revue Générale des Sciences for January 30, 1902, pp. 65–76; “Les Années Météores,” in “Le Cosmos,” Paris, May 25, 1889, etc.; “Terrestrial Magnetism,” March 1898, p. 7 for Chronological Summary of Authors re Aurora; Rev. Jas. Farquharson in “Abstracts of Sc. Papers Roy. Soc.,” Vol. II. p. 391; Wm. Dobbie, Phil. Mag., Vol. LXI for 1823, p. 252; W. Derham, for description of Auroras (in Phil. Trans. for 1728, p. 453); see, for Boscovitch, “Journal des Savants,” February 1864; “Journal des Savants,” for August 1820; C. H. Wilkinson, “Elements,” 1804; Vol. II. p. 279 and note; Calogera’s “Raccolta,” XVII. 47, Proc. of the Royal Soc. of Edinburgh for the observations of J. A. Brown and others on the aurora; F. C. Meyer, De luce boreali, 1726; Poggendorff, I. 135; Sturgeon, “Sc. Res.” 4th Sec. p. 489; Phil. Trans., Vol. XXXVIII. p. 243; Vol. XLVI. p. 499; F. Zöllner’s paper in “L. E. and D. Philos. Mag.,” for May and July, 1872; C. A. Young, Amer. Jour. of Sc., Vol. III., 3rd s., p. 69; Baron Karl Von Reichenbach’s “Physico-Physiological Researches,” trans. of Dr. John Ashburner, London, 1851, pp. 5–36, also pp. 445, etc., of the translation of Dr. W. Gregory, London, 1850; J. H. Van Swinden, “Recueil de Mémoires,” etc., La Haye, 1784, Vol. III. p. 187, etc.; J. E. B. Wiedeburg, “Beobachtungen und Muth.,” etc., 1771; G. W. Krafft, “Observ. Meteor,” etc., in Novi Com. Acad. Petrop., Vol. V. p. 400; Giuseppe Toaldo, “Descrizione,” etc., in Saggi ... Accad. di Padova, Vol. I. p. 178; Louis Cotte, “Table of Auroræ, Observed ... 1768–1779,” Paris, 1783; Journal de Physique for 1775; Recueil de Mem. de l’Acad. des Sciences for 1769; A. S. Conti, “Rifflessioni sull’ Aurora Boreale.”[48]
For Auguste Arthur De la Rive, consult “Bibl. Britan.,” Vol. XVI, N.S., 1821, p. 201, likewise the “Annales de Chimie et de Physique,” Phil. Mag., Phil. Trans., Comptes Rendus, more especially, as well as the “Bibl. Univ.” and the “Mem. de la Soc. de Genève,” at which latter place he was born in 1801.
For Jean Jacques d’Ortons de Mairan, consult “Mém. de Paris” for the years 1726, 1731–1734, 1747, 1751, also abridgments of the Phil. Trans. by Hutton, Vol. VII. p. 637, and by Baddam, 1745 ed., Vol. IX. pp. 490–497.
For W. Derham (1657–1735) consult also “Nouv. Biog. Gen.” (Hœfer), Vol. XIII. p. 712; the Phil. Trans. unabridged, Vol. XXIV. for 1704–1705, pp. 2136–2138; Vol. XXXVI. pp. 137, 204, also the following abridgments: Hutton, Vol. V. pp. 258–263; Hy. Jones, Vol. IV. part ii. pp. 290–291; Baddam, Vol. IV. pp. 473–478. In the last-named volume is thus given an account of Mr. Derham’s experiments: “He shows (Phil. Trans., No. 303, p. 2136) that, having consulted what others had writ of magnets, he finds in Grimaldi’s De Lumine et colore that both he and M. De la Hire (Phil. Trans., No. 188) had hit upon the same discovery before him.” Mr. Derham also alludes, more particularly, to the observations of Ridley, Barlow and Dr. Gilbert.
For Claudius—Claes—Arrhenius (1627–1694) Swedish scientist, professor at the Upsal University, consult “La Grande Encycl.,” Vol. III. p. 1107; “Dict. Biog. Suédois,” Vol. XXII. pp. 385–389.
For John Wallis, the celebrated English mathematician (1616–1703), in addition to the above-named Phil. Trans., Vol. XXIII for 1702–1703, p. 1106, consult Phil. Trans., Vol. XII for 1677, No. 135, pp. 863–866 (meteors), also the abridged editions as follows: Hutton, Vol. IV. pp. 196, 639, 655; Hy. Jones, Vol. IV. part ii. p. 286; Baddam, London, 1739, Vol. III. p. 228 and Vol. IV. pp. 100–104 (mariner’s compass); “Nouv. Biog. Gen.” (Hœfer), Vol. XLVI. p. 530.