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Simon Schaffer and Jan Golinski on Eudiometry October 17, 2009

Posted by Will Thomas in Schaffer Oeuvre.
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Landrianis eudiometer, from the Istituto e Museo di Storia della Scienza in Florence

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 (more…)