Questions:
(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.
|
|
|