Heat: Its measurement from Galileo to Lavoisier

Abstract — Professor Andrade has commented that the modern science of heat... may be said to have originated when a really clear distinction was made between heat and temperature. " This took place in the mid—l8th century and is primarily associated with Black, who introduced the concepts of latent heat and heat capacity. Temperature is the intensive property, the "quality", of heat, measured with a thermometer, an instrument dating from the early 17th century; the 'quantity " of heat was considered an extensive and conserved state function, analogous to the thermodynamic energy of today. In showing how heat changes could be measured, Black pioneered calorimetry. Of the many calorimetric studies in the second half of the 18th century, the most celebrated is that of Lavoisier and Laplace. In the 17th and 18th century studies of "heat " are to be found many of the origins of thermodynamics