POLAR REGIONS 



19 



tremely beautiful, and all of them, however complex, 

 pi'rt'rrlly symmetrical. * 



Hain is not unt'rcquent in the months of July and 

 August, and sometimes the quantity that falls in con- 

 tinued succession in a few days, is perhaps fully equal, 

 i u the time, to what occurs in tropical countries in the 

 rainy season, t 



The atmospheric phenomena of the Arctic regions are 

 peculiarly curious and interesting. This is more espe- 

 cially the case with regard to the aurora borealis, ha- 

 loes, parhelia, corona;, and anthelia, and the optical 

 i-lfects of unequal refraction. As these various pheno- 

 mena, however, are described under their respective 

 appellations, in the course of this work, we shall only 

 here state some few particulars respecting such as are 

 more peculiar to the Arctic regions. 



Haloes and parhelia were observed by Captain Parry, 

 in his voyage to Melville island, in very great perfec- 

 tion and variety. Sometimes the parhelia and prisma- 

 tic circles were numerous. The radius of the first halo 

 is stated, at different times, to have been 21 38' from 

 the sun, 22, 22* 10', 22 20 7 , &c. On one occasion, 

 there were two concentric prismatic circles, five segments 

 of circles, and three bright parhelia, all exhibited at 

 one time. J Sometimes similar phenomena, but less 

 bright, were observed round the moon. On the 26th 

 of January, there was a luminous circle encompassing 

 the moon of 22 40' radius, and a white horizontal 

 streak of light, forming prismatic spots of light, or 

 paraselenae, at the intersection with the halo. On an- 

 other occasion there were two circles of 38 and 46 

 radius round the moon, and four paraselenae on the 

 inner one. 



Coronae and anthelia were observed by Captain 

 Scoresby in the Greenland sea, almost daily in foggy 

 weather, whenever the sun was visible. The best po- 

 sition for seeing them was at the mast-head, where the 

 head of the shadow of the observer on the water was 

 always encompassed with an anthelion or glory. 

 Around this were several prismatic circles, from two to 

 five in number, all concentric and opposite to the sun. 

 The diameters were, No. 1, 1^ or 2; No. 2, the (ex- 

 terior limit) 4 45' ; No. 3, about 6 30 7 ; and No. 4, 

 (the middle of the band,) about 38 50'. The colours 

 of some of these circles were vivid and distinct, but of 

 others merely shades of a luminous grey.f ( 



But the most amusing, perhaps, of all the optical 

 phenomena observed in the Arctic regions, are those 

 produced by unequal refraction. In the height of sum- 

 mer, when the sky is clear, the constant action of the 

 sun produces a rapid evaporation from the sea and ice ; 

 but as the air, thus charged with moisture, passes over 

 alternate surfaces of water and ice, it becomes of very 

 unequal densities, forming various strata of different 

 degrees of refractive power. Hence objects seen through 

 such media are variously distorted images are multi- 

 plied the most fantastic forms are exhibited in an end- 

 less and ever varying succession. Captain Scoresby, 

 in his voyage to Greenland in 1 822, gives a number of 

 examples of these interesting phenomena. On one oc- 

 casion, there being a number of ships in sight at a time 

 when the atmosphere, though clear, was in a very ex- 

 traordinary condition, the appearances were particularly 

 curious. " Of some vessels, whose hulls were beyond 



the horizon, there were two, and of one ship three, cli- 

 tinct inverted images, each exhibited in a different 

 stratum of refracted ice, one above another, the low- * 

 est image being at an altitude of more than the apparent 

 height of the ship's mast, above the mast-head of the 

 original. And of two vessels there were well-defined 

 images, in an inverted position, though the ship* t> 

 which they referred were not within sight ! It should 

 be observed, that the inverted images were visible on 

 this occasion only, when an appearance of ice, produc- 

 ed either by reflection or refraction, occurred above the 

 regular line of the horizon, in the quarter occupied by 

 the ships. In the clear intervals of the lower atmo- 

 sphere, between the strata of refracted ice, no image 

 was seen ; and when the stratum wa too narrow to 

 comprise the whole of the image, a part of it only ap- 

 peared. And it should be also observed, that these 

 phenomena we^e principally telescopic, both the ship* 

 and images being so distant, that, to the naked eye. 

 they only appeared as indistinct specks. The inverted 

 images occurred either in the south-west or north-east 

 quarter ; but, at the same time, the ships in the north- 

 west quarter were only subject to a distortive influence 

 these appeared above a cliff of ice, elevated by re- 

 fraction, like oblong black streaks, lengthened out, 

 but compressed almost to the breadth of a line. 



The land also exhibited some curious appearances. 

 In many places there were patches resembling two ob- 

 tuse pyramids united by their apices, the upper one, 

 though quite as distinct as the other, being evidently 

 the inverted image only of the lower one. In occasion- 

 al positions, where two of these double pyramids were 

 near together, the upper limbs of the higher pyramid* 

 coalesced, so as to present the appearance of prodigious 

 bridges, some leagues in extent, with a clear atmo- 

 sphere beneath them. Sometimes these pyramids were 

 so compressed and multiplied, that three or four were 

 seen in a vertical series, forming so many distinct hori- 

 zontal strata, joining in the middle, but all detached at 

 the extremities. 



Thegeneral telescopic appearance of thesearcticcoasts, 

 when under the influence of unequal refraction, is fre- 

 quently that of an extensive ancient city, abounding 

 with the ruins of castles, obelisks, churches, and monu- 

 ments, with other large and conspicuous buildings. 

 Some of the hills often appear to be surmounted with 

 turrets, battlements, spires, and pinnacles ; while 

 others, subjected to another kind of refraction, exhibit 

 large masses of rock, apparently suspended in the air, 

 at a considerable elevation above the actual termination 

 of the mountains to which they refer. The whole exhibi- 

 tion isfrequently a grand und interesting phantasmagoria. 

 Scarcely is the appearance of any object fully examined 

 and determined, before it changes into something else. 

 It is, perhaps, alternately a castle, a cathedral, or an 

 obelisk : then expanding and coalescing with the ad- 

 joining mountains, it unites the intermediate valleys, 

 though they may be miles in width, by a bridge of a 

 single arch of the most magnificent appearance. 



Among all the optical phenomena of unequal refrac- 

 tion which Captain Scoresby mentions, the most ex- 

 traordinary appears to have been the discovery of his 

 father's ship, when many miles beyond the reach of 

 direct vision by its inverted image in the air. The 



Poir 



SPC Account of the Arctic Regions, vol. i. p. 4*5 132. 



f See Scoresby's Voyage to Greenland, 1822. 



* Parry's Voyage to t/ie Nortli-West, p. 15*, 156, 157, 168. 163, 16V, 172, 



Voyage to t/te Northern Wltak-jithery in 1823, p. i74, 88-k 



