The year was 1843, and the theme of English meteorology was measurement. Sir ‘Thunder-and-lightning’ William Snow Harris was given his last British Association for the Advancement of Science grant to complete the Plymouth series of over 120,000 thermometric observations, publication of which proved a costly venture, not least because the series implied no meteorological theory whatsoever.

In July of that year, however, John Herschel wrote to William Radcliffe Birt that the atmosphere might be considered ‘a vehicle for wave like movement which may embrace in their single swell & fall a whole quadrant of a globe’. The idea of ‘atmospheric wave’, thought Herschel, might well make sense of the odd series of London barometric readings made in September 1836, but, more significantly, it might also lead towards solving the notorious ‘storm controversy’ of the 1830s between the American meteorologists William Redfield and James Pollard Espy. If Birt would accept, Herschel would propose him to the British Association as the director of the new project to discover laws of weather behaviour.