The evaportion of ice.

When solids are heated they generally pass into a liquid and then into a gaseous state. Solids may, however, pass directly into a gaseous state without apparently passing through the intermediate stage, that is to say, solids evaporate. It is an established fact that ice and snow gradually disappear, and in the Artic regions where the temperature is always below 0°C, this is the only manner in which evaporation can occur. The process is termed sublimation. [...