§ Mr. Onslowasked the Postmaster-General what research has been conducted by his Department or other official bodies into the behaviour of the refractor index of the atmosphere in the first few hundred feet above the earth's surface; and what probability this research has revealed that subrefraction to reduce the radio radius of the earth to a value less than its true radius will be experienced in any part of the United Kingdom.
§ Mr. MasonResearch work into the behaviour of the refractive index of the lower atmosphere has been conducted by the Science Research Council (formerly D.S.I.R.) in Bedfordshire over a period of several years. Based on this work, my experts estimate that subrefraction, sufficient to reduce the radio radius of the64W earth to a value less than its true radius, exists for about 5 per cent. of the time in the South of England.