simple snow cave or burrow by digging into the side of a snowdrift and lining the hole with grass or brush. Snow caves must be ventilated. If the snow is not deep enough to support a roof, dig a trench in a drift and roof it with snow blocks or other materials. In wooded country, make a tree-pit shelter if snow is deep enough. Enlarge the natural pit around a tree trunk and roof it with any available covering. P r e v e n t  c a r b o n  m o n o x i d e  p o i s o n i n g  by providing good ventilation in closed shelters in which a fire is burning. Do not sleep directly on the snow. Put insulation under your sleeping bag or body. Lay a thick bough bed shingle fashion; or use seat cushions, a parachute canopy, or even an inverted and inflated life raft if available. ARCTIC SUMMER.— If you stay with the aircraft, use it for shelter. Cover openings with netting or parachute cloth to keep insects out. Do your cooking outside to avoid carbon monoxide poisoning. Make your fire at a safe distance from the aircraft. Make a simple outdoor shelter by hanging a parachute over the wing of the aircraft; anchor the ends to the ground by weighting them down with stones. You can quickly improvise a tent by placing a rope or pole between two trees or stakes and draping a parachute over it; make the comers fast with stones or pegs. Shelter against rain and insects will be needed. Choose a campsite near water but on high, dry ground if possible. Stay away from thick woods, as mosquitoes and flies will make your life miserable. A good campsite is a ridgetop, the shore of a cold lake, or a spot that gets an onshore breeze. A fine shelter for drizzly weather and pro- tection against insects is a tepee made from the parachute. In it you can cook, eat, sleep, dress, and make signals—all without going outdoors. Use 6 panels of parachute for a two-man shelter and 12 to 14 panels for a three-man paratepee. This shelter is worth building if you decide to stay in one spot for some time. Avoid sleeping on the bare ground. Provide some sort of insulation under yourself; soft boughs or an inflated life raft provides excellent insulation. Pick a bed site on level, well-drained ground free from rocks and roots. If you have to sleep on bare ground, dig depressions for your hips and shoulders and try out the site before you set up your shelter or spread your bedding. Signaling Build your fire on a platform so that it will not sink in the snow. A standing spruce tree near a timberline burns readily even when green. Build a “bird nest” of quickly flammable material in the branches to ensure a quick start. Tramp out signals in the snow. Fill them in with boughs, sod, moss, or water colored with fluorescent dye. In brush country, cut conspicuous patterns in vegetation. In tundra, dig trenches; turn sod upside down at the side of the trench to widen your signal. A parachute tepee stands out in the forest or on the tundra in summer, especially at night with a fire inside. Remember, sound does not carry well through snow. If the entire party is in a snow cave or igloo, you may not hear rescue aircraft. Keep someone on guard as a spotter. Build the spotter a windbreak but do not roof it. Signal with smoke by day and bright flame by night. Add engine oil, rags soaked in oil, or pieces of rubber (matting or electrical insulation) to the fire to make black smoke; add green leaves, moss, or a little water to send up billows of white smoke. Keep plenty of spare fuel on hand. Signaling aids, such as flares and smoke grenades, must be kept dry. Use them only when friendly aircraft are sighted or heard. Signal with a flashlight or, if the aircraft landing lights are intact and you can get the engine to run, remove the lights and extend them for signaling; but do not waste the battery—save it for the radio. Arrange your ground signals in big geometric patterns rather than at random-they will attract more attention that way. Use the fluorescent dye available in the life raft or life preserver kit for signaling on water or snow. Use it carefully; a little goes a long way. Use it only downwind, because the fine dye will penetrate clothing or food. On rivers, throw it out into the current for a quick spread. Water Problems Water is not a serious problem in the Arctic. An abundant supply of pure water is available from streams, lakes, ponds, snow, and ice. Pollution should not be a problem. The Arctic is an area that is usually too cold for bacterial growth. Therefore, in the Arctic almost any source of water can be used. During the winter, melt snow or ice for drinking water. Do not eat unmelted snow or 5-31