§ Mr. Russellasked the Secretary of State for Air the causes of the unusual amount of fog which occurred during January, especially in South-East England.
Mr. WardWe had two spells, each lasting several days, with very little cloud, and no wind. In these conditions heat is lost from the ground and from the air immediately above it, and the water vapour in the air condenses. In the winter months the heat from the sun during the day does little to compensate for that lost during darkness. The fogs last month were also intensified by the wet state of the ground. During the past fifty-two years, a spell of this kind has on the average occurred in January once every two or three years.