Josiah Willard Gibbs (1839-1903)
American physicist and one of the founders of statistical mechanics. He was born in New Heaven, Conneticut, and studied in Yale; he was good at mathematics and Latin. After obtaining a degree in engineering, he became a tutor at Yale, and then spent three years in Europe (France and Germany), and studied physics under eminent scholars such as Kirchhoff or Helmholtz.
He became a professor of mathematical physics at Yale in 1871. Then in 1873, he published two important papers on thermodynamics (Graphical Methods in the Thermodynamics, and A Method of Geometrical Representation of the Thermodynamic Properties). At this time, many eminent scholars did not have good understanding of the concept of entropy; surprizingly, even James Clerk Maxwell misunderstood it, and he acknowledged, in his 1873 paper, that he corrected his understanding thanks to one of Gibbs's 1873 papers (I owe this point to my student Kazuko Inoue; see her Master's thesis).
Aside from other important works in mathematical physics and chemistry, he established an elegant theory of statistical mechanics in his Elementary Principles in Statistical Mechanics (1902).
See a biography in MacTutor History of Mathematics