In 1876, Josiah Willard Gibbs wrote an article called, On the Equilibrium of Heterogeneous Substances.

One milestone was the publication in 1876 by Josiah Willard Gibbs of his paper, On the Equilibrium of Heterogeneous Substances.

In the history of thermodynamics, On the Equilibrium of Heterogeneous Substances is a 300-page paper written by American mathematical-engineer Willard Gibbs.

His subsequent and most important publication was "On the Equilibrium of Heterogeneous Substances" (in two parts, 1876 and 1878).

Gibbs's paper "On the Equilibrium of Heterogeneous Substances"

He described that research in a monograph titled "On the Equilibrium of Heterogeneous Substances", published by the Connecticut Academy in two parts that appeared respectively in 1875 and 1878.

The publication of the paper "On the Equilibrium of Heterogeneous Substances" (1874-78) is now regarded as a landmark in the development of physical chemistry.

A complete theoretical treatment of the subject was given by J. Willard Gibbs in his work On the Equilibrium of Heterogeneous Substances (1875-8).

On the Equilibrium of Heterogeneous Substances New Haven, 1878.

In 1876, Willard Gibbs unified all of this in his 300-page "On the Equilibrium of Heterogeneous Substances".