Skip to 0 minutes and 6 secondsHumphry Davy's first major scientific discovery was the physiological effects of nitrous oxide, which established his national reputation. Davy moved from Penzance to Bristol in October 1798 to run the Medical Pneumatic Institution, the MPI. By the start of the following year, 6 Dowry Square had been acquired as the location for the MPI. Davy oversaw the work to convert it into a fully equipped scientific site, including a laboratory where investigations into the therapeutic possibilities of the many gases discovered during the 18th century could be undertaken. The MPI opened at the end of March 1799, and Davy soon began investigating the physiological properties of dephlogisticated nitrous air, as Priestley, its discoverer, had named it.

Skip to 0 minutes and 52 secondsDavy initially termed the gas nitrous phosoxyd, known in Lavoisier's nomenclature as gaseous oxide of azote, or nitrous oxide. Davy claimed that he'd undertaken some work on the gas while still in Penzance, but because of lack of apparatus could not then pursue it. Once the laboratory at the MPI became operational, Davy immediately returned to experimenting on the gas during April 1799. Originally, Davy made impure gas. And when he and others, such as the poet Robert Southey, inhaled it, only limited effects were produced, such as faintness, giddiness, and slower pulse. In Davy's early accounts, his nitrous oxide experiments are not especially detailed. They give no indication as to the volume of the gas that he and others inhaled, or for how long.

Skip to 1 minute and 42 secondsThis changed in the second half of April, when Davy began recording both these crucial experimental circumstances. On the 18th April, in the presence of Beddoes and others, Davy undertook many experiments, including breathing 16 quarts, just over 18 litres, in seven minutes, which had the effect of making him, as he wrote, "dance about the laboratory as a madman." On the other hand, when the physician Peter Roget later of Thesaurus fame inhaled nitrous oxide, he experienced vertigo and tingling in his hands, and did not, as he put it, "experience the least pleasure from any of these sensations." This and other inconsistencies presented Davy and Beddoes with difficulties in interpretation.

Skip to 2 minutes and 25 secondsSignificantly, with some specific individuals, they were able to create the circumstances which reversed negative effects to be more in line with what Davy observed on himself. The primary aim of the MPI was to investigate the therapeutic value of gases and there were some limited clinical trials. For example, when the gas was administered to a hemiplegic patient, Beddoes claimed that, as a consequence, he threw away his crutch and walked without support, leaving Beddoes to conclude that, as he wrote, the present will be the most splendid era in medicine. But it was the pleasurable effects that attracted most notice. And a wildly enthusiastic Southey referred to nitrous oxide as a wonder-working gas.

Skip to 3 minutes and 9 secondsHe wrote to a friend-- "I have been breathing a newly discovered gas which produces the most extraordinary effects. Laughter, a delightful sensation in every limb, in every part of the body, to the very teeth, an increased strength with no after relaxation. It is a high pleasure for which language has no name, and which can be estimated by no known feeling. I took some this morning, and still feel increased strength and spirits." Davy, as might be expected, wrote a poem. 'Not in the ideal dreams of wild desire / Have I beheld a rapture wakening form / My bosom burns with no unhallowed fire / Yet is my cheek with rosy blushes warm.

Skip to 3 minutes and 59 seconds/ Yet are my eyes with sparkling lustre filled / Yet is my mouth replete with murmuring sound / Yet are my limbs with inward transport thrilled / And clad with newborn mightiness around' While Davy was away in Cornwall during November 1799, clearly recovering from his overuse of the gas, Beddoes publishes Notice of Some Observations Made at the Medical Pneumatic Institution. Beddoes's text received a coruscating review in the pro-government Anti-Jacobin Review. This probably prompted Davy, concerned with his future prospects, to seek alternative employment. And in March 1801, he moved to the recently opened Royal Institution in London. Davy was at the beginning on his metropolitan career.

Davy’s Nitrous Oxide Experiments

Watch this video in which Professor Frank James from the Royal Institution talks about Davy’s experiments.

  • What do you think Davy and his Bristol circle were hoping for with their experiments into nitrous oxide?
  • What were the recorded effects?

Please share your thoughts by posting a comment on these questions, or on anything else that you would like to discuss.

NB. When Professor Keith Hanley reads Robert Southey’s letter to Davy we are showing you onscreen a page from Davy’s notebook. You can read Southey’s whole letter by visiting the Romantic Circles website.

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This video is from the free online course:

Humphry Davy: Laughing Gas, Literature, and the Lamp

Lancaster University