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.
Aurora Australis, or Southern Polar Light
The earliest account of this phenomenon was given by Don Antonio de Ulloa, as will be seen under date A.D. 1735–1746.