The summer of 1799 saw a new fad take root in a certain circle of British society: the inhalation of nitrous oxide, also known as "laughing gas." The pioneer of these experiments was a young Humphry Davy, future President of the Royal Society, whose descriptions of being under the influence, as well as those penned by his clique, are among the most remarkable in the history of science. From its subsequent use in "laughing gas shows" through to its eventual employment in anaesthetics, the "delectable air" would go on to inspire more than a century of extraordinary writings that combined the...