<p style='text-align: justify;'>John William Strutt, 3rd Baron Rayleigh, was the Cavendish Professor from 1879 to 1884. His research covered a huge range of topics. Among his most important works are the discovery of argon, Rayleigh scattering, which explains why the sky is blue, and his work on acoustics collected in the textbook 'Theory of Sound'. He agreed to hold the Cavendish chair for only five years, after which he returned to his estates at Terling Place in Essex where he had his own extensive laboratories.</p>