The Eudiometer at Tintern

The Cavendish Eudiometer

Contributor: Tim Fulford

Location: The Wye Valley/The Royal Institution

Description: In 1800 a man inspired by Wordsworth’s visionary poetry made a trip to Tintern Abbey. Based in Bristol, he was a friend of Coleridge and Southey and was in the midst of editing Lyrical Ballads for the press; he also wrote nature verse in his own right. He was employed, however, not as a poet but as a scientific enquirer, and on his excursion to the river Wye he was armed with an improved eudiometer—the best instrument for measuring the proportion of oxygen, the gas first isolated by Joseph Priestley, in the atmosphere. ‘The Eudiometer’, he wrote, ‘that I have lately used is a very simple & commodious one – It consists of a tube about 5 inches long containing 200 grains of water – The space between the 140 & 180 grains is graduated. – This tube is emptied of water in an atmosphere when you wish to know its composition & plunged into a solution of muriate or sulphate of iron impregnated with Nitrous gas.’(1) He was Humphry Davy…

…and he had been inducted, before he ever left his home county, Cornwall, into a culture that valued both experimental and poetic enquiry into nature. In 1797-8, Gregory Watt, the son of the engineer and chemical enquirer James Watt, wintering on the Cornish coast to benefit his consumptive lungs by its fresh air, encouraged the teenaged Davy to design experiments and to record them in notebooks; there, these early investigations of air, heat and light shared pages with poetic evocations of his ecstatic responses to sun, sea and breeze. Hired on Watt’s recommendation as the assistant at Bristol’s new Pneumatic Institution, Davy impressed his employer, Thomas Beddoes, with his scientific writing and gained Southey’s admiration of his poetry. By 1799 he had published in both fields with their help; he had also begun an intensive programme of pneumatic experiments—on himself and on the Bristol intellectuals—that promised to reveal the formative and curative influence of gases on the body, brain and mind.

The trip to Tintern was the newest of these—a field trip designed to test the atmosphere of the river valley that had lulled Wordsworth with its gentle breezes

Until, the breath of this corporeal frame,
And even the motion of our human blood
Almost suspended, we are laid asleep
In body, and become a living soul:
While with an eye made quiet by the power
Of harmony, and the deep power of joy,
We see into the life of things.

(‘Lines Composed a Few Miles above Tintern Abbey’, lines 44-50)

Davy wanted to see as Wordsworth had seen. In a letter describing the trip, he wrote ‘Our design was to see Tintern Abbey by moonlight; and it was perfectly accomplished. [. . .] viewing for three hours all the varieties of light & shade which a bright full moon & a blue sky could exibit in this magnificent ruin; and wandering for three days among the colored woods & rocks surrounding the river between Monmouth & Chepstow’. (2) To see—and to write about seeing—in this way was to be inspired. But inspiration was more than a metaphor. Davy’s instrument allowed it to be tested. What the eudiometer promised to reveal was the extent to which the inspiration conferred by respiring the air of the Wye valley had material causes: nature’s healing powers, restoring bodily and mental vitality, really were breathed in. Thus Davy’s instrument was a quintessential Romantic thing: the eudiometer offered to demonstrate poetic metaphors’ chemical and physiological validity and to reveal the interdependence of man and nature as parts of the ‘economy of vegetation’ (the description of oxygen and photosynthesis used by Beddoes’s mentor and Priestley’s friend Erasmus Darwin). (3)

Unfortunately, the instrument was not sensitive enough to demonstrate the special properties of the Wye valley’s oxygen-rich breezes and to trace inspiration to its material cause (though it was the forerunner of today’s devices for detecting atmospheric pollution). Davy noted, ‘On analysing after our return the air collected from Monmouth, from the woods on the banks of the Wye, & <from> the mouth of the Severn, there was no perceptible difference. They were all of similar composition to the air in middle of Bristol. ie they contained about 22 pr cent oxygene – The air from the bladders of some sea weed apparently just cast on shore at the old passage likewise gave 22.’ (4) Nor did administering oxygen or the still more recently discovered gas – nitrous oxide – to consumptives cure their diseases. The eudiometer is a poignant token of early Romanticism’s millenarian hopes and of the disappointment of those hopes. Poetic and scientific experiment would never come so close to each other again as they did at Tintern in 1800.

  1. Davy described the instrument and his experiments on the composition of air in ‘An Account of a New Eudiometer’, Journal of the Royal Institution, 1 (1802), 45-48.
  2. Letter 28, of October 1800, in The Collected Letters of Sir Humphry Davy, ed. Tim Fulford and Sharon Ruston (Oxford: Oxford University Press, 2020).
  3. The eudiometer was invented by Marsilio Landriani (1751-1815) and used by Horace-Bénédict de Saussure (1740-99) in 1788 to measure the composition of the air on an Alpine col. In 1802, Alexander von Humboldt (1769-1859) carried one almost to the top of Mount Chimborazo in the Andes to measure the composition of the air at still more elevated heights
  4. On the eudiometer and Davy’s experimental predecessors with it, Henry Cavendish (1731-1810) and Claude Louis Berthollet (1748-1822), see Simon Schaffer, ‘Measuring Virtue: Eudiometry, Enlightenment, and Pneumatic Science’, in The Medical Enlightenment of the Eighteenth Century, ed. Andrew Cunningham and Roger French (Cambridge, 1990), pp. 281-318.

Date: 1800

Subject: Humphry Davy

Media rights: Henry Cavendish’s Eudiometer. From the Collections of the Royal Institution. Image reproduced by permission of the Royal Institution.

Object type: Scientific instrument

Format: glass, metal

Publisher: Collections of the Royal Institution.

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