Solar distillation of water from soil and plant materials: a simple desert survival technique.

Water obtained from soil and plant materials by a simple distillation technique can provide a means for survival under desert conditions. A hemispherical hole in soil (in some cases containing cut plant material) is covered with plastic film formed and held in a conical shape by a rock placed in the center. Water collects on the under side of the plastic, runs to the point of the cone, and drops into the container. A yield of 1.5 liters per day of potable water was obtained from a single "survival still."