Josiah Willard Gibbs
Gibbs is recognized as one of the early leaders in accepting the algebra of vectors to be the language of physical sciences. He first published his version of vector analysis in 1881 and 1884 while lecturing on the subject for many years at Yale. James Clerk Maxwell, the premier physicist of his time, even constructed 3-d models using Gibbs' work.
Moreover, two new concepts developed in his papers On the Equilibrium of Heterogeneous Substances (1890s) are taught until this very day. Chemists all know his work on the phase rule and chemical potential energy.