Poetry has celebrated its beauty, and to convey an adequate representation of its soft and variegated 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 connecting heaven and earth. [Illustration: Lunar Rainbow.] The principles which account for the formation of the rainbow explain the appearance of beautiful irridescent arches which have occasionally been observed 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 opposite to that of the sun, 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 rainbow. In the middle between these two places, and on the same horizontal line, there was a colored 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 color. 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 were 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 meadows; 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 colored.