534 



PHYSICAL GEOGRAPHY. 



fountain, and the dew upon the grass. There is hardly any other object of nature more 



pleasing to the eye, or soothing to 

 the mind, than the rainbow, when 

 distinctly developed a familiar 

 sight in all regions, but most com- 

 mon in mountainous districts, 

 where the showers are most fre- 

 quent. Poetry has celebrated its 

 beauty, and to convey an adequate 

 representation of its soft and va- 

 riegated tints, is the highest 

 achievement of the painter's art. 

 While the Hebrews called it the 

 Bow of God, on account of its 

 association with a divine promise, 

 and the Greeks the Daughter of 

 Wonder, the rude inhabitants of 

 the North gave expression to a 

 fancy which its peculiar aspect 

 might well create, styling it the 

 Bridge of the Gods, a passage con- 

 necting heaven and earth. 



The principles which account for 



the formation of the rainbow explain the appearance of 

 beautiful irridescent arches which have occasionally been ob- 

 served during the prevalence of mist and sunshine. Mr. Cochin 

 describes a spectacle of this kind, noticed from an eminence 

 that overlooked some low meadow grounds, in a direction op- 

 posite to that of the un, which was shining very brightly, a 

 thick mist resting upon the landscape in front. At about the 

 distance of half a mile from each other, and incurvated, like 

 the lower extremities of the common rainbow, two places of 

 peculiar brightness were seen in the mist. They seemed to rest 

 on the ground, were continued as high as the fog extended, the 

 breadth being nearly half as much more as that of the rainboAV. 



Tn the middle, between these two places, and on the same horizontal line, there was a 

 coloured appearance, whose base subtended an angle of about 12, and whose interior 

 parts were thus variegated. The centre was dark, as if made by the shadow of some 

 object resembling in size and shape an ordinary sheaf of corn. Next this centre there 

 was a curved space of a yellow flame colour. To this succeeded another curved space 

 of nearly the same dark cast as the centre, very evenly bounded on each side, and tinged 

 with a faint blue green. The exterior exhibited a rainbow circlet, only its tints were 

 less vivid, their boundaries Avere not so well defined, and the whole, instead of forming 

 part of a perfect circle, appeared like the end of a concentric ellipsis, whose transverse 

 axis was perpendicular to the horizon. The mist lay thick upon the surface of the mea- 

 dows ; the observer was standing near its margin, and gradually the scene became fainter, 

 and faded away, as he entered into it. A similar fog-bow was seen by Captain Parry 

 during his attempt to reach the North Pole by means of boats and sledges, with five 

 arches formed within the main one, and all beautifully coloured. 



The iris lunaris, or lunar rainboAV, is a much rarer object than the solar one. It 



