The Clement-Desormes experiment is reviewed. By reason of a finite difference between the pressure within the system and its surroundings, Bertrand and McDonald have criticized the usual consideration of the adiabatic expansion as reversible. Garland, Nibler and Shoemaker oppose, defining regions through virtual boundaries where the surroundings do not operate. For Holden, the use of virtual boundaries is expendable. Experiments cannot support a hypothesis testing due to experiment's intrinsic uncertainty. The role of polytropy in uncertainty is discussed. Both thermodynamic definitions and kinetic model depict the real processes as irreversible phenomena and the reversible ones as a limiting hypothetical case.
heat capacity; reversible; Clement-Desormes
