Josiah Willard Gibbs (11.02.1839-28.04.1903) was an American theoretical physicist and a member of the National Academy of Sciences. He was born in New Haven. He graduated from Yale University (1863). He furthered his studies at the universities of Paris, Berlin and Heidelberg. From 1869 he worked at Yale University (professor from 1871).
His main work was in the fields of chemical thermodynamics and statistical mechanics, of which he is one of the founders. He developed the so-called entropy diagrams, which play a large part in engineering thermodynamics, and showed (1871—73) that three-dimensional diagrams make it possible to represent all the thermodynamic properties of a substance. With the papers “Graphical Methods in the Thermodynamics of Fluids” and “A Method of Geometrical Representation of the Thermodynamic Properties of Substances by Means of Surfaces” (1873) he founded geometrical thermodynamics. He laid (1873—78) the foundations of chemical thermodynamics; in particular he developed the general theory of thermodynamic equilibrium and the method of thermodynamic potentials, formulated (1875) the phase rule, constructed the general theory of surface phenomena, and obtained the equation relating the internal energy of a thermodynamic system to the thermodynamic potentials. He developed the theory of capillarity. The results of this research of Gibbs's were, however, almost unknown in Europe until 1892. He was the first to work out a general approach that makes it possible to express the thermodynamic properties of any chemical system in terms of the microscopic mechanical properties of its molecules. With the work “Elementary Principles in Statistical Mechanics, Developed with Especial Reference to the Rational Foundation of Thermodynamics” (1902) he completed the creation of classical statistical physics. His name is attached to the Gibbs paradox, the canonical, microcanonical and grand canonical Gibbs distributions, the Gibbs adsorption equation and the Gibbs — Duhem equation. He is also one of the creators of vector calculus in its modern form. A Fellow of the Royal Society (1897). Copley Medal (1901).