The impact of Rayleigh’s ‘‘The Theory of Sound’’ on the British development of the theory of electromagnetic radiation

At the time of Maxwell’s death in 1879, British physicists had not yet formulated models for the generation of electromagnetic waves. A recent history of British electromagnetic theory of that period [B. J. Hunt, The Maxwellians (Cornell U. P., Ithaca, 1991)] notes the influence Rayleigh’s text on sound had on the calculation of the power radiated by an oscillating magnetic dipole, which G. F. FitzGerald published in 1883. Examination of a series of FitzGerald’s papers on sources of electromagnetic waves for the years 1879, 1880, 1882, and 1883 confirms Hunt’s observations. Specifically, FitzGerald credits Rayleigh’s text for the inspiration to consider traveling‐wave solutions, the key to his eventual success, instead of his earlier standing‐wave solution. This anecdote, and others to be noted from that period, illustrate the influence of acoustics in helping to resolve difficulties in cases in which the electromagnetic theory was poorly understood. These may be of interest to today’s students and teachers.