The Lavoisier-Laplace Calorimeter

(see 4 Questions below)

In 1782-84 the device below was used by Lavoisier and the young mathematician Pierre Simon de Laplace to measure the content of the "element" caloric in a sample of combustible oil. (The is the same Laplace for whom was named the "Laplacian", the sum of x,y,z curvatures in quantum mechanical kinetic energy.)

In brief: the oil was burned in a lamp (Fig 8) held in a bucket (Fig. 9) held in a wire mesh cage (f) surrounded by ice in spaces b and a of the double walled container a foot in diameter. The lid (F) was topped with ice, as was a mesh lid (not shown) beneath it that covered the inner volume b.  


(1) How did the calorimeter work?

(2) What was the purpose of the "double-bagging" with ice?

(3) Why does Lavoisier insist in his instructions that the ice used must not be colder than 0°C?

(4) Note that the lid (F) has two tubes to allow blowing fresh air into the apparatus. Why is this necessary? Do you foresee a problem for the experiment because of this exchange of air? Is it serious?

Here is a picture (from Poirier, p. 138) of the actual device, which was evaluated at 300 pounds ($12,000) in Lavoisier's estate. It is presently at the Musée des Arts et Métiers in Paris.

Photo and exchange rate from J.P. Poirier, Lavoisier: Chemist, Biologist, Economist, R. Balinsky, trans., U. Pennsylvania Press, 1996.

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copyright 2000 J.M.McBride