4. In order to illustrate the effect of an extraordinarily low temperature on the human frame, the best point to start from is the imagination of a man exposed without clothes to its influence. At 37° or 50° (C.) of cold a misty halo would encompass him, the edges of which would have, under certain circumstances, the colours of the rainbow. It is evident that the moisture of the body rapidly coming forth and becoming visible in the cold air would cause this mist, which would decrease with the heat of the body, and disappear on the death of the frozen man. The purpose of clothing is to counteract as much as possible this twofold loss of warmth and moisture, which is the principal cause of the fearful Arctic thirst. But even clothed men exposed to so low a temperature present a strange appearance. When they are dragging a sledge on the march their breath streams forth like smoke, which is soon transformed into a mass of needles of ice, almost hiding their mouths from view; and the snow on which they tread steams with the heat which it receives from the snow beneath. The countless crystals of ice, which fill the air and reduce the clearness of day to a dull yellow twilight, make a continual rustling noise; their fall in the form of fine snow-dust, or their floating as frosty vapour, is the cause of that penetrating feeling of damp which is so perceptible when the cold is intense, and which receives accretions from the vapours issuing from the open places of the sea. Notwithstanding all this, there is an indescribable dryness in the atmosphere, strongly contrasting with the feeling of dampness. Heavy clouds are impossible; the heavens are covered only by mists, through which the sun and the moon, surrounded by halos, glow blood-red. Falls of snow, as we understand the expression, altogether cease; the snow crystals, under the influence of cold, are so minute as to be almost invisible. The land, the real home and source of cold, acts as the great condenser of vapour, and snow and moisture of every kind, and lies under a deep covering of frozen snow till the colour of its walls and precipices reappears in April. The soil, in the stricter sense of the word, is frozen as hard as iron wherever it appears through the snow, and the mean temperature of Franz-Josef Land (about 3° F.) makes it highly probable, that the frost penetrates to the depth of a thousand feet. Great cold, calm weather, and clear atmosphere combined, are the characteristics of the interior of Arctic countries. The nearer we approach the sea, the rarer is this combination. Light breezes sometimes occur with a temperature 37° (C.) below zero,[35] but the atmosphere is then less transparent.