It was a title that could not fail to catch the eye - "Nitrous Oxide and William Shakespeare". Was laughing gas to be revealed as a secret ingredient in the Bard's comedies? Alas, no. The paper, to be delivered this week at the Challenger Society for Marine Science's centenary conference, did indeed start with Shakespeare's observation that the "canopy of air" seemed "a foul and pestilent congregation of vapours". But then Jon Barnes and colleagues at Newcastle University and the Plymouth Marine Laboratory remarked: "In hindsight, these words seem prophetic in light of global warming" before embarking on a thoroughly worthy examination of nitrous oxide's role as a greenhouse gas. Shakespeare's connection turned out to be little more than hot air.