The Influence of Molecular Constitution Upon the Internal Friction of Gases (Classic Reprint)

Excerpt from The Influence of Molecular Constitution Upon the Internal Friction of Gases

By the internal friction or viscosity of a gas, is meant the friction between two adjacent layers of the gas, which are moving in parallel directions but not with the same velocity. It is proportional to the relative velocity and the area of Con tact of the two layers. The coefficient of internal friction is the constant factor, depending upon the kind of gas under consideration, which, when multiplied by the difierence in velocity, gives the friction per square unit of surface of contact of the two layers.

Although there is no sensible cohesion between the par ticles of a gas, as there is in liquids and solids, the tendency of a moving layer of gas to impart its own velocity to a layer in contact with it, has been satisfactorily explained according to the kinetic theory of gases. As is well known, all the molecules of a gas are supposed to be constantly in rectilinear motion, rebounding in straight lines with undiminished ve locity, after collision with one another or a solid wall. In virtue of its mass and velocity each molecule possesses mo~ mentum. When one layer Of gas is moving over another, there is a constant passage of molecules from each layer into the other. There is then an interchange of momentum, the result being a tendency to equalize the velocities of the two layers. We see thus that the effect of friction is produced between two layers of gas which are not moving with the same velocity in the same direction.

It has been demonstrated1 that the coefficient of friction of a gas.

About the Publisher

Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com

This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.