(1976) Detente, Larousse,
http://www.larousse.fr/archives/grande-encyclopedie/page/4197 extract: The question arose whether the expansion of a gas in a vacuum, that is to say without external work, involving a change in temperature of the gas, assumed thermally insulated (expansion to constant internal energy); LJ Gay-Lussac then JP Joule have concluded in the negative, but their experiences were not very precise; GA Hirn (1865) brought to light a slight cooling.

has been cited by the following article:

• TITLE: Thermodynamics and Irreversibility: From Some Paradoxes to the Efficiency of Effective Engines

  AUTHORS: Olivier Serret

  KEYWORDS: Heat Transfer, External and Internal Pressure Work, Internal Energy, Reversible and Irreversible, Joule’s Law and Joule’s Experiments, Adiabatic and Free Expansion, Clapeyron Diagram, Carnot Cycle, Engine Efficiency

  JOURNAL NAME: Journal of Modern Physics, Vol.5 No.16, October 20, 2014

  ABSTRACT: The traditional thermodynamic theory explains the reversible phenomena quite well, except that reversible phenomena are rare or even impossible in practice. Here the purpose is to propose an explanation valid for reversible and also irreversible phenomena, irreversibility being common or realistic. It previously exposed points tricky to grasp, as the sign of the work exchange, the adiabatic expansion in vacuum (free expansion) or the transfer of heat between two bodies at the same temperature (isothermal transfer). After having slightly modified the concepts of heat transfer (each body produces heat according to its own temperature) and work (distinguishing external pressure from internal pressure), the previous points are more easily explained. At last, an engine efficiency in case of irreversible transfer is proposed. This paper is focused on the form of thermodynamics, on “explanations”; it does not question on “results” (except the irreversible free expansion of 1845...) which remain unchanged.