Ice calorimeter, late 18th century.
© Science Museum / Science & Society Picture Library
This ice calorimeter belonged to the French scientists Antoine Lavoisier (1743-1794) and Pierre-Simon Laplace (1749-1827). With this apparatus, the amount of heat given out by a heated object as it cooled can be measured. A warm object is placed in the basket, and ice is packed around it. The temperature of the ice remains at freezing as it melts with heat from the hot object. The object cools down to the same temperature as the ice, then the melted ice is let out of the calorimeter at the bottom to be weighed. Lavoisier and Laplace used the apparatus in 1785 to demonstrate that respiration in animals is a proces of slow combustion.