the semblance of a flaming column, having lost his spherical form; and Agatharcides," nec sol ab disci formam se habet, sed crassam refert columnam principio." The same phenomenon is described by Mrs Elwood,' as seen at Cosseir on the Red Sea. Although some of these meteors are most probably electrical, others are caused by reflexions of light from the snowcrystals floating in the atmosphere. The suggestion of Christie and Lubbock, that the vertical columns at sunset seen in this country, arise from reflexions upon an undulating stratum of liquid air in the higher regions of our atmosphere, seems, together with the hypothesis of Poisson,' upon which it rests, altogether untenable. In establishing this theory of the condition of the upper stratum of our atmosphere, besides the difficulties to be overcome in the possibility of obtaining a liquid atmosphere from cold alone,—such as that of the temperature of space,-there are optical objections sufficient to overturn the hypothesis. We would not close this section without referring to the curious optical phenomenon of Blue suns. These have been frequently observed in the West Indies, Africa, over the whole of Italy, and the south of France. Babinet has suggested an explanation which Brewster has adopted. The phenomenon appears to depend upon the presence of vesicular vapour in the atmosphere, the different media of which, produce upon light in its passage, effects similar to those of mixed plates. It may be imitated by soap lather between plates of glass, the bubbles representing the vesicular globules through which the light passes, in media having different degrees of refrangibility. 1 Hudson,-Geog. Minor. Agathar.; Diodor. lib. iii. cap. 3; Crichton's Arab. vol. i. p. 74,-Ed. Cab. Lib. Trav. in Egypt, 1830. Traité de Mécanique, tom. ii. p. 612; Théorie Math. de la Chaleur, p. 460; Athen. No. 519, P. 743. Rozet, Voy. dans la Régence d'Alger. Athen. Sept. 21. 1844. CHAPTER XI. 273. The Looming. 274. Mirage,—its cause. 275. Curious refraction of coast of France; of Dover castle. 276. Figures in the air; Spectre of Souter-fell. 277. Spectral ships. 278. Remarkable mirage at Birkenhead. 279. Singular atmospheric refractions on the Geneva lake. 280. Fog-banks. 281. Fata Morgana. 282. Curious mirages at Youghall. 283. Appearance from Brighton Cliff; and Etna. 284. Enchanted coast. 285. See-kote. 286. Chittram, or Sehrab of the Desert. 287. Witnessed in India. 288. Iceblink. 289. Spectre of the Brocken. 290. Spectre of Skiddaw, and Ben Lomond. "Far distant images draw nigh." WORDSWORTH,-Evening Ode. "Fierce fiery warriors fight upon the clouds, In ranks, and squadrons, and right form of war." Julius Caesar, act. ii. sc. ii. 273. The Looming is an unusual atmospheric refraction presenting an apparent increased elevation of objects. The phenomenon may be observed towards the close of a warm summer day, when the hills in the distance seem greatly magnified. Mrs Somerville' makes mention of the chain of the Himalayas having started into view to a spectator on the plains of Hindostan, after a heavy shower following a lengthened drought. Walls' witnessed this phenomenon at Hudson's Bay, in 1769; and Scoresby3 mentions that points on the coast of Greenland, distant 160 miles, could sometimes be distinctly seen, though not more than 4000 feet high. In the antarctic regions the same phenomenon has been seen; thus Sir James C. Ross' observes," During the afternoon, an un 1 Connex. Phys. Sc. sect. 18, p. 184, 2d ed. 2 Thomson's Ilist. Roy. Soc. 4to, p. 229. Voy. of Discovery. "Journal, pp. 105-108. usual degree of refraction was remarked to the south-westward, which had the effect of bringing at times clearly into view land which we had not before seen, and then again removing it from our sight." This land, then 100 miles distant, was Cape Anne. Upon the 21st of June 1819, at 8 P. M., the thermometer being 44°, when Captain Colby' and Lieutenants Robe and Dawson, R. E. were ranging the Caithness coast with a theodolite telescope, from Corryhabbie hill in Banffshire, elevated not more than 2550 feet above the sea,-they distinctly saw a brig sailing to the westward, in the Pentland Frith, between Dunnet and Duncansby Heads; the ship was then from 90 to 100 miles distant. The night and day preceding the phenomenon had been continually rainy and misty; the clouds continued on the hill till seven o'clock that evening. Professor Lloyd' mentioned to the British Association in 1837, that he had seen from Dublin, the Welsh hills from their very valleys, so distinctly, that the larger inequalities on the surface of the mountains were vividly depicted. The atmosphere was then clear and loaded with invisible moisture, for immediately thereafter it rained heavily. Sir David Brewster conjectures, that on such occasions the intervening air actually becomes a magnifying lens of large proportions. Travellers in the desert have often been deceived by the same phenomenon, into the belief that they were approaching a stately tree, when it was merely a tiny shrub, and thus their hopes of shelter from an ardent sun and burning desert, have been painfully disappointed." M. Delcros, while making a barometrical measurement of the profile of Mount Jura, in 1813, found that atmospheric refraction was modified by horary circumstances, and that with singular constancy,-leading him to say that the coefficient of refraction was only constant in its inconstancy. This led to a daily exhibition of the looming, more regular, however, than that phenomenon generally occurs. In the morning, the 1 Ed. Phil. Jour. vol. i. P. 411. 2 Brit. Assoc. 1837; Athen. No. 517, p. 692. Tod's Annals and Antiq. of Rajasthan or Rajpootana, 4to, Lond. 1829-32. signal on the Oberhergheim was invisible from his station near Ensisheim in Alsace, neither could he detect an enormous poplar which grew near it. About 3 P.M., however, he began to perceive the top of the tree above the horizon; soon thereafter the black ball of the signal appeared, and then its entire pyramid of twenty metres elevation, which was visible till five o'clock. Towards evening another change took place; the signal looked like a very obtuse pyramid on the top of an apparent hill, produced by refraction from the plain, and the poplar was reduced to a diminutive size, the phenomenon now disappeared, and till next day after noon, the signal was not seen. 274. When the object appears inverted, the French and Italians designate the phenomenon Mirage and Fata Morgana, described so early as the 17th century by the learned Jesuit Kircher. The greater number of these singular meteors arise from the irregular refraction of light passing through strata of air of unequal density; through such media, the rays will be bent in curves, the convexity being upwards when they pass above that portion of the atmosphere which is most dense, and downwards when below that stratum, producing an elevated appearance of the object, and by the entrance of a double pencil of rays, an inverted image: others depend upon the reflexion of objects upon dense fogs strongly illuminated. We shall notice some of the most interesting of these phenomena. 275. Mr Latham, F. R. S., on the 26th of July 1798, at 5 P. M., had his attention drawn to a beautiful appearance of the mirage witnessed at Hastings, by the numbers of persons running to the beach to behold the wonder. The coast of France, from Calais to Dieppe, had become distinctly visible, and the fishermen were pointing out and naming the places wont to be visited by them. By help of a glass the fishingboats were seen at anchor off the French coast; Dungeness, which is 16 miles from Hastings, and runs two miles into the sea, was apparently close at hand, and the vessels sailing were much magnified; the phenomenon lasted till sunset. On the 6th of August 1806, about 7 P. M., Dr Vince when at Ramsgate, saw the whole of Dover Castle, as if upon the Ramsgate side of a hill which obscures the castle, excepting the turrets, from that town. Between Ramsgate and the land from which the hill rises, almost six miles of sea intervene, and about the same distance thence to the castle, which stands upon a cliff about 320 feet above the sea. During the continuance of this beautiful mirage, the castle was so vividly depicted that the hill did not itself appear through the image.1 276. Analogous to this, is the remarkable appearance of troops of soldiers and horsemen exercising in the air, or reflected to the opposite side of the hill where they are assembled. One of the earliest records of this phenomenon is given by Josephus,' on the testimony of several witnesses. There were seen, says he, on the 21st of the month Artemisius*, shortly after the pascal feast, up and down the air before sunset, chariots and armed men, all over the country, passing along with the clouds round about the city. Holinshed' records several instances, some of which were doubtless auroræ boreales. Upon the 4th of October 1835, a phenomenon of this kind was seen at Chewton, on one of the Mendip hills in Wilts, about 6 P. M. It represented a large body of troops moving onwards with drawn swords; their position and space were often changed, and so distinctly were they visible, that the very trappings of the horses, and the several accoutrements of the soldiers, could be distinguished; the phenomenon lasted above an hour. It was afterwards ascertained that a body of yeomanry were practising about fifteen miles off. A similar appearance, which has been called the spectre of Souter-fell, is thus described by Mr James Clark. "On a summer's evening in the year 1743, when Daniel Stricket, servant to John Wren of Wilton Hall, was sitting at the door along with his master, they saw the figure of a man with a 'Ed. Roy. Tr. vol. vi. p. 245. 6 2 See "An Alarm to a Secure Generation," by John Howie of Lochgoin, 1780, where many visions are recorded. Joseph. Wars of the Jews, vii. 12; L'Estrange's Trans. fol. 547. Iyar or Zif, i. e. Apr. or May. Chron. vol. ii. pp. 59, 132, vol. iii. pp. 220, 249, 395, 773, 1313. Survey of Lakes of Cumberland. |