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.
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.
Buried, or in Holes.--A European can live through a bitter night, on a perfectly dry sandy plain, without any clothes besides what he has on, if he buries his body pretty deeply in the sand, keeping only his head above ground. It is a usual habit of the naked natives in Australia to do so, and not an unfrequent one of the Hottentots of South Africa. Mr. Moffat records with grateful surprise how he passed a night, of which he had gloomy forebodings, in real comfort, even luxury, by adopting this method. A man may be as comfortable in a burrow as in a den. I shall speak of underground houses under "Hutting;" and for the present will only mention that, in arid countries, dry wells, dug by natives and partially choked by drifted sand, are often to be met with. They are generally found near existing watering-places, where they have been superseded by others, better placed and deeper. Now, there are few warmer sleeping-places than one of these dry wells; a small fire is easily kept burning at the bottom, and the top may be partially roofed over.
In Ashes of Camp Fire.--A few chill hours may be got over, in a plain that affords no other shelter, by nestling among the ashes of a recently burnt-out camp fire.
Warm Carcases.--In Napoleon's retreat, after his campaign in Russia, many a soldier saved or prolonged his life by creeping within the warm and reeking carcase of a horse that had died by the way.
By the water-side.--A stony beach makes a fine dry encamping-place, and has this advantage, that it makes it impossible for marauders to creep up unheard. But the immediate neighbourhood of fresh water is objectionable, for, besides being exposed to malaria and mosquitoes, the night air is more cold and penetrating by its side, than at one or two hundred yards' distance from it. (I will speak of walls of rushes and reeds, under "Huts.")
By Rocks.--In the cruel climate of Thibet, Dr. Hooker tells us that it is the habit to encamp close to some large rock, because a rock absorbs heat all day, and parts with it but slowly during the night-time. It is, therefore, a reservoir of warmth when the sun is down, and its neighbourhood is coveted in the night-time. Owing to the same cause, acting in the opposite direction, the shadow of a broad rock is peculiarly cool and grateful, during the heat of the day, in a thirsty land.
On Heather.--Mr. St. John tells us of an excellent way in which Highland poachers, when in a party usually pass frosty nights on the moor-side. They cut quantities of heather, and strew part of it as a bed on the ground; then all the party lie down, side by side, excepting one man whose place among the rest is kept vacant for him. His business is to spread plaids upon them as they lie, and to heap up the remainder of the heather upon the plaids. This being accomplished, the man wriggles and works himself into the gap that has been left for him in the midst of his comrades.