20 



Polar 

 Regions. 



account of this circumstance, by Captain Scoresby, 

 who had just returned from his first landing on the 

 east coast of Greenland, at Cape Lister, in latitude 

 70 3W N. is thus given in his Journal. " It was about 

 11 P.M. the night was beautifully fine, and the air quite 

 mild. The atmosphere, in consequence of the warmth, 

 being in a highly refractive state, a great many curious 

 appearances were presented by the land and icebergs. 

 The most extraordinary effect of this state of the at- 



POLAR REGIONS. 



effect of refraction equal to 8500 feet. Now, the 

 angle corresponding with an altitude of 8500 feet, and 

 a distance of 140 miles, is 34' 47", the value of the 

 extraordinary refraction, at the time the land was thus 

 seen ; or, calculating in the proportion of the distance, 

 which is the most usual manner of estimating the re- 

 fraction, it amounted to one-fourth of the ai'ch of dis- 

 tance, instead of one-twelfth, the mean quantity. 

 That land was seen under these circumstances, 



mosphere, however, was the distinct inverted image of there cannot be a doubt; for it was observed to be in 



a ship in the clear sky, over the middle of the large the same position, and under a similar form, on the 



bay or inlet before mentioned, the ship itself being 18th, 23d, 24th, and 25th July, 1821, when the ship 



. 1 1 1 ,1 V _ _ " A . Ann *\F fr VtlC -w.rn n !*- 1y\" SVt f 1 1 rf"l rV/MTrt 1 >) O Q/"i' +f\ 1 1 O C.f\f \\7 ,,.-,! _ 



entirely beyond the horizon. Appearances of this 

 kind I have before noticed, but the peculiarities of this 

 were, the perfection of the image, and the great dis- 

 tance of the vessel that it represented. It was so ex- 

 tremely well defined, that when examined with a tele- 

 scope 'by Dollond, I could distinguish^ every sail, the 

 general " rig of the ship," and its particular character; 

 insomuch that I confidently pronounced it to be my 

 father's ship, the Fame, which it afterwards proved to 

 be, though, on comparing notes with my father, I 

 found that our relative position at the time gave our 

 distance from one another very nearly thirty miles, 

 being about seventeen miles beyond the horizon, and 

 some leagues beyond the limit of direct vision. I was 

 so struck by the peculiarity of the circumstance, that I 

 mentioned it to the officer of the watch, stating my full 

 conviction that the Fame was then cruizing in the 

 neighbouring inlet." 



Another effect of this state of the atmosphere is to 

 render directly visible objects which in reality are en- 

 tirely beyond the horizon. This takes place in some 

 measure in temperate, and perhaps torrid, as well as in 



was in longitude from 12 30', to 11 50' W. and on 

 the 23d it remained visible for twenty-four hours to- 

 gether; and though often changing its appearance, 

 by the varying influence of the refraction, it constantly 

 preserved a uniformity of position, and general simi- 

 larity of character. In my journal of this day, I find I 

 have observed, that my doubts about the reality of the 

 land were now entirely removed, since, with a tele- 

 scope, from the mast-head ' hills, dells, patches of 

 snow, and masses of naked rock, could be satisfactorily 

 traced, during four- and- twenty hours successively.' 

 This extraordinary effect of refraction, therefore, I' 

 conceive to be fully established." 



The only other optical phenomena that we shall de- 

 scribe, is the ice-blink. " On approaching a pack, field, 

 or other compact aggregation of ice, the phenomenon of 

 the ice-blink is seen whenever the horizon is tolerably 

 free from clouds, and in some cases even under a thick 

 sky. The ice-blink consists of a stratum of a lucid white- 

 ness, which appears over ice in that part of the atmo- 

 sphere adjoining the horizon. It appears to be occa- 

 sioned thus: Those rays of light which strike on the 



the frigid climates. But in the latter the exhibition of snowy surface of the ice, are reflected into the superin- 

 cumbent air, where they are rendered visible, either by 

 the reflective property of the air, simply, or by a light 

 haze, which, on such occasions, probably exists in the 

 atmosphere ; but the light which falls on the sea, is in 

 a great measure absorbed, and the superincumbent air 

 retains its native ethereal hue. Hence, when the ice- 

 blink occurs under the most favourable circumstances, 

 it affords to the eye a beautiful and perfect map of the 

 ice, twenty or thirty miles beyond the limit of direct 

 vision, but less distant in proportion as the atmosphere 

 is more dense and obscure. The ice-blink not only 

 shows the figure of the ice, but enables the expe- 

 rienced observer to judge whether the ice thus pictured 

 be field or packed ice: if the latter, whether it be 

 compact or open, bay or heavy ice. Field-ice affords 

 the most lucid blink, accompanied with a tinge of yel- 

 low ; that of packs is more purely white ; and of bay- 

 ice, greyish. The land, on account of its snowy cov- 

 ering, likewise occasions a blink, which is more yellow 

 than that produced by the ice of fields." 



this phenomenon is more frequent and more remarkable 

 than in any other region. Captain Scoresby gives se- 

 veral examples of it in his Account of the Arctic Re- 

 gions, vol. i. pp.,384 391. But in his Journal of a 

 Voyage to Greenland, the most singular example oc- 

 curs. " The particulars were these: Towards the end 

 of July 1821, being among the ice in latitude 74 10', 

 and longitude, by lunar observation and chronometer, 

 (which agreed to twenty-two minutes of longitude, or 

 within six geographical miles,) 12" 30' 16" W. land 

 was seen from the mast-head to the westward, occa- 

 sionally, for three successive days. It was so distinct 

 and bold, that Captain Manby, who accompanied me 

 on that voyage, and whose observations are already 

 before the public, was enabled, at one time, to take a 

 sketch of it from the deck, whilst I took a similar 

 sketch from the mast-head, which is preserved in my 

 journal of that year. The land at that time nearest to 

 us was Wollaston Foreland, which, by my late sur- 

 veys, proves to lie in latitude 74 25' (the middle 

 part of it,) and longitude 19 50': the distance, there- 

 fore, must have been at least 120 miles. But Home's 

 Foreland, in 21 W. longitude, distinguished by two 

 remarkable hummocks at its extremities, was also 

 seen ; its distance, by calculation, founded on astrono- 

 mical observations, being 140 geographical, or 160 

 English miles. In an ordinary state of the atmo- 

 sphere (supposing the refraction to be one-twelfth of 

 the distance), any land to have been .visible from a 

 ship's mast-head, an hundred feet high, at the distance 

 of 140 miles, must have been at least two nautical 

 miles, or 12,000 feet in elevation ; but as the land In 

 question is not more than ;3500 feet in altitude, (by 

 estimation,} there roust havg been an extraordinary 



SECT. Vl.Phyiology. 



Before we enter the arctic regions, we find the ve- 

 getable productions of the earth progressively dimi- 

 nishing in size and in number, as we recede from the 

 equator. The noblest trees of the forest in temperate 

 climes cannot vie in size with the vast adansonia, or 

 the superb palms of the torrid regions, the giants of 

 vegetable life: and, in advancing toward the poles, 

 there is a striking diminution of the number of vege- 

 table speciesw Wildenow states the number of known 

 species on the Coromandel coast, and in the island of 

 Jamaica, at 4000 ; in England 2592 ; in the Mar- 



Polar 



Regions. 



