REYNOLDS, OSBORNE - THERMAL OSMOSIS & THERMAL TRANSPIRATION.

On certain Dimensional Properties of Matter in the Gaseous State. Part I. Experimental Reseraches on Thermal Transpiration of Gases through Porous Plates and on the Laws of Transpiration and Impulsion, including an Experimental Proof that Gas is not a continuous Plenum. Part II. On an Extension of the Dynamical Theory of Gas, which includes the Stresses, Tangential and Normal, causedby a varying Condition of Gas, and affords an Explanation of the Phenomena of Transpiration and Impulsion. Received January 17, - Read February 6, 1879.

(London, Harrison and Sons, 1879). 4to. No wrappers as extracted from "Philosophical Transactions" 1879 - Vol. 170 - Part II. Pp. 727-845 and 3 plates. The plates slightly brownspotted, otehrwise fine and clean.

First printing of this classic paper on "thermal respiration" in which Reynolds explains how some of the movements of the vanes in Crookes' Radiometer can be accounted for.

"The correct solution to the problem (the problem of finding the cause of the movement of the vanes in Crooke's radiometer) was provided qualitatively by Osborne Reynolds, better remembered for the "Reynolds number". Early in 1879 Reynolds submitted a paper to the Royal Society in which he considered what he called "thermal transpiration", and also discussed the theory of the radiometer. By "thermal transpiration", Reynolds meant the flow of gas through porous plates caused by a temperature difference on the two sides of the plates. If the gas is initially at the same pressure on the two sides, it flows from the colder to the hotter side, resulting in a higher pressure on the hotter side if the plates cannot move. Equilibrium is reached when the ratio of pressures on either side is the square root of the ratio of absolute temperatures. This counterintuitive result is due to tangential forces between the gas molecules and the sides of the narrow pores in the plates. The effect of these thermomolecular forces is very similar to the thermomechanical effects of superfluid liquid helium. This liquid, which lacks all viscosity, will climb the sides of its container towards a warmer region. In fact, this form of liquid helium climbs so quickly up the sides of a thin capillary tube dipped into it, that a fountain is produced at the tube's other end."(Philip Gibbs).

Order-nr.: 42660