Jules Augustin Frédéric Regnault was a French stock broker's assistant who first suggested a modern theory of stock price changes in Calcul des Chances et Philosophie de la Bourse (1863) and used a random walk model. He is also one of the first authors who tried to create a "stock exchange science" based on a statistical and probabilistic analysis. His hypotheses were used by Louis Bachelier, who is considered a pioneer in the study of financial mathematics. Bachelier had anticipated many of the mathematical results developed in Albert Einstein’s 1905 paper.