Some primitive methods of refrigeration

Before the advent of mechanical refrigeration, the water was kept cold, being stored in semi-porous earthen jars, so that the water escaped through the walls and evaporated. Evaporation dissipated heat and cooled the water. This system was used by the Egyptians and the Indians of the American Southwest. Often the natural ice of the lakes and rivers was cut off during the winter and stored in straw-lined caves or wells and later in isolated sawed buildings to be removed as needed. The Romans carried snow from the Alps to Rome, in cargo troops, to cool the emperors' drinks. Although these cooling methods employed natural phenomena, they were used to keep the temperature low in a space and could therefore be called refrigeration.