On the Thermal Effects of Fluids in Motion. Received June 15, - Read June 16, 1853.

(London, Richard Taylor and William Francis, 1853) 4to. No wrappers as extracted from "Philosophical Transactions" 1853, Vol. 143 - Part III. Pp. 357-365. Textillustrations. Clean and fine. First appearance of this highly importent paper in the development of thermodynamics, describing the experiments leading to the discovery of the cooling effect when a gas is allowed to expand freely. This is the founding theory, later used in refrigeration."The only substantial contribution to thermodynamics to which the joint names of Joule and Thomson are attached belongs to an idea conceived by Thomson, who saw the possibility of analyzing the deviations of gas properties from the ideal behavior. In particular a non-ideal gas, made to expand slowly through a porous plug so as to approximate a specified mathematical condition - constant enthalpy), would in general undergo cooling (essentially a transformation of atomic motion into work spent against the interatomic attractions).But the appliocation of the Joule-Thomson effect to technology of refrigeration belongs to a later stage in the development of thermodynamics."(DSB VII, p. 182).The Joule-Thomson effect or Joule-Kelvin effect describes the increase or decrease in the temperature of a real gas (as differentiated from an ideal gas) or a liquid when allowed to expand freely through a valve or other throttling device while kept insulated so that no heat is transferred to or from the fluid, and no external mechanical work is extracted from the fluid. The Joule-Thomson effect is an isenthalpic process, meaning that the enthalpy of the fluid is constant (i.e., does not change) during the process. It is named for James Prescott Joule and William Thomson, 1st Baron Kelvin who established the effect in 1852, following earlier work by Joule on Joule expansion in which a gas expands at constant internal energy. The Joule-Thomson effect is sometimes referred to as the Joule-Kelvin effect. Engineers often refer to it as simply the J-T effect.…