If memory serves, Hotelling cited DuPuit in his 1938 Econometrica article on
marginal-cost pricing.


Also, Nicholas Theocarakis writes that Walras was not "well schooled" in
mathematics. Perhaps not, but he used a lot of it. His "Theorie Mathematique
du Prix des Terres" is one example. Perhaps he was teaching himself math as
he wrote, for it is mathematically prolix, but perhaps also no earlier
economist had developed the math of finance. Interestingly a German
forester, Martin Faustmann (1849), wrote a classic on valuation of forest
lands, but there seems to have been a wall between foresters and economists.

Mason Gaffney