John Ashworth Ratcliffe, 12 December 1902 - 25 October 1987

Abstract

When Ratcliffe began research in the Cavendish Laboratory in 1924, ‘wireless’, as it was then called, had started its rapid advance to become a major science. The thermionic valve had been coming into use in World War I. The BBC had been formed and broadcasting had started in 1922. The large Post Office transmitter at Rugby, call sign GBR, frequency 16 kHz, was being built in 1923-24. The presence of conducting regions in the upper atmosphere had been surmised from the work of Balfour Stewart on terrestrial magnetism, and the idea of elevated conducting surfaces to explain the propagation of wireless waves to great distances had been used in some mathematical papers. It was as a branch of physics that wireless had the greatest appeal for Ratcliffe. In his final undergraduate year he had attended lectures by E. V. Appleton (later Sir Edward Appleton, F.R.S.) and they impressed him with the fact that wireless covered a very large part of physics and depended on phenomena discovered in the pure research of the physics laboratory. His first book (1929) was entitled The physical principles of wireless , and when he later organized a Physical Society conference in Cambridge in 1954 he gave it the title ‘The physics of the ionosphere’. In this way the subject now known as ionospheric physics was launched. Ratcliffe was also deeply interested in the applications of electrical science and in the advance of wireless as a part of electrical engineering, and he was to become President of the Institution of Electrical Engineers 1966-67. His teaching and his research were closely linked. He used to say that teaching was his main job and research was a hobby. But he also said that university scientists are paid to teach and promoted for research. He enjoyed lecturing and had the highest reputation for clarity of presentation. His books and papers are models of clear exposition and many of his students would say that in the use of English for scientific explanations he excelled all others.