Importance of Comfort.—­To conclude these general hints, let the traveller, when out in trying weather, work hard at making his sleeping-place perfectly dry and comfortable; he should not cease until he is convinced that it will withstand the chill of the early morning, when the heat of the yesterday’s sun is exhausted, and that of the coming sun has not begun to be felt.  It is wretched beyond expression for a man to lie shivering beneath a scanty covering and to feel the night air become hourly more raw, while his life-blood has less power to withstand it; and to think, self-reproachfully, how different would have been his situation if he had simply had forethought and energy enough to cut and draw twice the quantity of firewood, and to spend an extra half-hour in labouring to make himself a snugger berth.  The omission once made becomes irreparable; for in the cold of a pitiless night he has hardly sufficient stamina to rise and face the weather, and the darkness makes him unable to cope with his difficulties.

Bivouac in Special Localities.—­Encampment in Forests.—­A clump of trees yields wonderful shelter.  The Swedes have a proverb that “the forest is the poor man’s jacket.”  In fir-woods there is great facility in making warm encampments; for a young tree, when it is felled, yields both poles to support branches for shields against weather, and finer cuttings for flooring above the snow or damp.  A common plan is to support a cross-bar by two uprights, as shown in the figure; against this cross-bar a number of poles are made to lean; on the back of the poles abundance of fir branches are laid horizontally; and lastly, on the back of these are another set of leaning poles, in order to secure them by their weight.

[Sketch of pole shelter].  On Bare Plains.—­Avoid sleeping in slight hollows during clear still weather.  The cold stratum of air, of which I spoke in the section of “Shelter from the Sky,” pours down into them, like water from the surrounding plain, and stagnates.  Spring frosts are always more severely felt in hollows.  Therefore, in a broad level plain, especially if the night be clear and calm, look out for some slightly rising ground for an encampment.  The chilled stratum of air drains from off it, and is replaced by warmer air.  Horses and cattle, as the night sets in, always draw up to these higher grounds, which rise like islands through the sea of mist that covers the plain.

Walls have been built for shelter against the wind, on a bare sandy plain, by taking empty bags, filling them with sand, and then building them up as if they had been stones.