James Clerk Maxwell investigates the kinetic theory…

James Clerk Maxwell investigates the kinetic theory of gases.

Originating with Daniel Bernoulli, this theory had been advanced by the successive labors of John Herapath, John James Waterston, James Joule, and particularly Rudolf Clausius, to such an extent as to put its general accuracy beyond a doubt; but it receives enormous development from Maxwell, who in this field appears as an experimenter (on the laws of gaseous friction) as well as a mathematician.

In 1866, he formulates statistically, independently of Ludwig Boltzmann, the Maxwell–Boltzmann kinetic theory of gases demonstrating that temperatures and heat involve only molecular movement.

His formula, called the Maxwell distribution, gives the fraction of gas molecules moving at a specified velocity at any given temperature.

In the kinetic theory, temperatures and heat involve only molecular movement.

This approach generalizes the previously established laws of thermodynamics and explains existing observations and experiments in a better way than had been achieved previously.

Maxwell's work on thermodynamics leads him to devise the thought experiment that will come to be known as Maxwell's demon.