The annual meeting of the British Association for the Advancement of Science, founded in 1831 and attended by “300 gentlemen”, quickly became the leading scientific event in Great Britain, the place where important advances were announced and great issues debated. The British Science Festival, as it is now called, takes place in Aberdeen from September 4 to 9. Below Clive Cookson selects his highlights from the event’s illustrious 19th-century past and looks forward to next week’s festival.