On such sunny days, the strong contrasts of light and shade between the glistening snow and the dark protruding rocks produce a remarkable deception in the apparent distance of the land, along a steep mountainous coast. When at the distance of twenty miles from Spitzbergen, for instance, it would be easy to induce even a judicious stranger to undertake a passage in a boat to the shore, from a belief that he was within a league of the land. At this distance the portions of rock and patches of snow, as well as the contour of the different hills, are as distinctly marked as similar objects in many other countries, not having snow about them, would be at a fourth or a fifth part of the distance. Nothing can be more wonderful than the phenomena of the atmosphere dependent on reflection and refraction, which are frequently observed in the Arctic seas, particularly at the commencement or approach of easterly winds. They are probably occasioned by the commixture, near the surface of the land or sea, of two streams of air of different temperatures, so as to occasion an irregular deposition of imperfectly condensed vapor, which when passing the verge of the horizon apparently raises the objects there situated to a considerable distance above it, or extends their height beyond their natural dimensions. Ice, land, ships, boats, and other objects, when thus enlarged and elevated, are said to loom. The lower part of looming objects are sometimes connected with the horizon by an apparent fibrous or columnar extension of their parts; at other times they appear to be quite lifted into the air, a void space being seen between them and the horizon. A most remarkable delusion of this kind was observed by Scoresby while sailing through the open ice, far from land. Suddenly an immense amphitheatre inclosed by high walls of basaltic ice, so like natural rock as to deceive one of his most experienced officers, rose around the ship. Sometimes the refraction produced on all sides a similar effect, but still more frequently remarkable contrasts. Single ice-blocks expanded into architectural figures of an extraordinary height, and sometimes the distant, deeply indented ice-border looked like a number of towers or minarets, or like a dense forest of naked trees. Scarcely had an object acquired a distinct form, when it began to dissolve into another. It is well known that similar causes produce similar effects in the warmer regions of the earth. In the midst of the tropical ocean, the mariner sees verdant islands rise from the waters, and in the treeless desert fantastic palm-groves wave their fronds, as if in mockery of the thirsty caravan.