Jules Dupuit

Who was Jules Dupuit?

Jules Dupuit was an Italian-born French civil engineer and economist.

He was born in Fossano, Italy then under the rule of Napoleon Bonaparte. At the age of ten he emigrated to France with his family where he studied in Versailles — winning a Physics prize at graduation. He then studied in the École Polytechnique as a civil engineer. He gradually took on more responsibility in various regional posts. He received a Légion d'honneur in 1843 for his work on the French road system, and shortly after moved to Paris. He also studied flood management in 1848 and supervised the construction of the Paris sewer system. He died in Paris.

Engineering questions led to his interest in economics, a subject in which he was self-taught. His 1844 article was concerned with deciding the optimum toll for a bridge. It was here that he introduced his curve of diminishing marginal utility. As the quantity of a good consumed rises, the marginal utility of the good declines for the user. So the lower the toll, the more people who would use the bridge. Conversely as the quantity rises, the willingness of a person to pay for that good declines.