Diagram of a eudiometer, from the Museo Galileo in Florence
First off, apologies for slow posting—things have been too bananas recently to indulge blog-related side interests. I’m hoping things clear up soon, but I’m presenting my research on Antarctic research at 4S here in DC at the end of the month, so things may remain at a trickle until November. However, before it got too desolate around here, I did want to parachute in and do a quick write-up on eudiometry. Our article is: Simon Schaffer, “Measuring Virtue: Eudiometry, Enlightenment, and Pneumatic Medicine” in The Medical Enlightenment of the Eighteenth Century, Andrew Cunningham and Roger French, eds., 1990, pp. 281-318. A close companion work is Jan Golinski’s Science as Public Culture: Chemistry and Enlightenment in Britain, 1760-1820, Cambridge UP, 1992, esp. pp. 117-128. I won’t try and distinguish the two treatments here.
The technology of the eudiometer is based on Joseph Priestley’s “nitrous air test”, devised in 1772. A good explanation of the nitrous air test as well as a computer animation of how eudiometers worked are available from the Museo Galileo in Florence (for modern scientific explanation, see the animation here). The basic idea is that manufactured nitrous air (nitrogen oxide) is mixed with a sample of ambient air. Part of the mixture dissolves into water leading to a decreased volume of now-unrespirable air in the chamber, which can be measured. Priestley (1733-1804), understanding the respirability of air to be reflective of its virtue, and understanding respiration to transfer phlogiston from the body to the air, understood the remaining air to be phlogisticated by the test, and the test to be a measure of the “goodness” of the common air used.
Italian experimenters, beginning with Felice Fontana and Marsilio Landriani replicated the test, embodying it in an instrument that Landriani called a eudiometer, which taken from Greek literally means a measuring instrument of the goodness of the air. Through the 1770s and 1780s eudiometry became a common pursuit for men of science throughout Enlightened Europe as they conducted tours to gather air samples from various locales, transported the samples in vials, and compared measurements of quality. The demonstration of the unhealthy quality of air in such putrid environments as marshes, cemeteries, and sewers supported medical and hygiene improvement projects advocated by enlightened authorities, such as the prescription of novel airs as medical therapies, hospital reform, the removal of corpses from graveyards (a move hotly contested by clergy) and swamp draining (note the Italian for “bad air” is mala aria). The eudiometer did not create the concept of the quality of air—it was also measured by smell or by timing the deaths of small animals in enclosed containers—but it did help turn the measurement of air into a quintessentially ambitious Enlightenment project (see also the establishment of the meter). Schaffer makes the point as only he can: “To use the nitrous air test as a tool of medical meteorology was to become committed to a more complex account of the cosmos and the social order” (290).
Priestley himself never promoted the broad eudiometry project, but as an enlightened philosopher, he did approve of it. The eudiometer was a simple instrument, which not only made evident the utility of knowledge in the formulation of good policy, it could be widely used to replicate and demonstrate philosophical arguments, including to public audiences. The eudiometer was also well-attuned to Priestley’s phlogistic chemistry. Notably, through the mid-1770s, Lavoisier in Paris also took its measurements to be a demonstration of the effectiveness of Priestley’s chemical philosophy.
By the end of the 1770s, though, complexity began to upset the program of nitrous air eudiometry. There was more variance in the quality of air at the same location over time than between different locations, and the simplicity of the device was undermined as questions arose such as by what method should nitrous air be created? did the water absorbing the air have to be distilled? and so on. Priestley’s own isolation of “dephlogisticated air” in 1775 upset the principle that the best common air represented a pure standard. In 1777 Alessandro Volta (1745-1827) introduced eudiometry using inflammable air (hydrogen) rather than nitrous air, which further challenged the clear links between combustion, respiration, and pneumatic virtue. Italian eudiometry proponents and French chemists soon began to understand the processes taking place in eudiometers as varied chemical processes with only an oblique connection to matters of health. By the early 1780s Priestley himself had abandoned medical eudiometry, though some continued to pursue it, even as Lavoisier reinterpreted the instrument’s operation in terms of his chemistry of oxygen, which would over the next decades replace the phlogiston concept to which Priestley would continue to adhere.
A word on Golinski’s book (his first): it is a history of different varieties of chemical practice toward the end of the eighteenth century and at the beginning of the nineteenth, spanning Cullen, Black, Priestley, to Davy. He acknowledges the “inspiration” of Schaffer, and the book reads a lot like what a solo book by Schaffer might be like if Schaffer wrote books. In 1990 Golinski had written what amounts to perhaps the best consolidation of 1980s methodological gains, “The Theory of Practice and the Practice of Theory: Sociological Approaches in the History of Science,” Isis 81 (1990): 492-505; for expanded coverage see his 1998 book Making Natural Knowledge: Constructivism and the History of Science (1998, 2nd ed. 2005). Consolidation of gains is a particularly apt term here, because Golinski has a talent for taking and elucidating the best of ideas and not saying much about the rest, except for maybe a mildly critical aside slipped in here and there. If you want a good guide to the up-side of constructivist historiography, go to Golinski.
The generic title, “Science as Public Culture” is a clear nod to the use of history as a path to conceptual understanding that arose in the 1980s, as is his sociology-heavy introduction’s explanation of the need to challenge and explain a general notion of science as a “public” activity. Ultimately, though, the book doesn’t have much to say about “science as public culture”, but Golinski does use the idea of analyzing scientific work as an activity of public interest to turn in a really fine history of chemical experimentation’s various public ramifications and institutional manifestations in the period, of which enlightened eudiometry was one. Even if you don’t work on this era, I’d recommend reading it. It’s very informative.