Arsene Jules Etienne Dupuit

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 Ecole Polytechnic 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 consumes rises, the marginal utility of the good declines for the user. So the lower the toll (lower marginal utility), the more people who would use the bridge (higher consumption). Conversely as the quantity rises (people allowed on the bridge), the willingness of a person to pay for that good (the price) declines.

Thus, the concept of diminishing marginal utility should translate itself into a downward-sloping demand function. In this way he identified the demand curve as the marginal utility curve. This was the first time an economist had put forward a theory of demand derived from marginal utility. Although not the first time that the demand curve had been drawn, it was the first time that it had been proved rather than asserted.

Jules Dupuit’s logic was suspect in that it skipped over the fact that marginal utility is particular to an individual, while market demand is an aggregate. Nothing was said on the interpersonal comparability of utility in order to connect personal marginal utility to aggregate demand. Dupuit, however, did not draw a supply curve and thus did not get price-determination into his story.

Dupuit went on to define ‘relative utility’ as the area under the demand/marginal utility curve above the price and used it as a measure of the welfare effects of different prices – concluding that public welfare is maximized when the price (or bridge toll) is zero. This was later known as Alfred Marshall’s consumer surplus.

Jules Dupuit’s reputation as an economist does not rest on his advocacy of laissez-faire economics (he wrote ‘Commercial Freedom’ in 1861) but on frequent contributions to periodicals. Wanting to evaluate the net economic benefit of public services, Dupuit analysed capacities for economic development, and attempted to construct framework for utility theory and measuring the prosperity derived with public works.

He also wrote on monopoly and price discrimination.

Major Works of Jules Dupuit

– Essais et expériences sur le tirage des voitures et sur le frottement de seconde espèce, 1837
– Considérations sur le frais d’entretien des routes, 1842, Annales des ponts et chaussées
– Mémoire sur le tirage des voitures et sur le frottement de roulement, 1842, Annales des ponts et chaussées
– On the Measurement of the Utility of Public Works, 1844, Annales des ponts et chaussées
– Études théoritiques et pratiques sur le mouvement des eaux courantes, 1848
– De l’influence des peages sur l’utilite des voies de communication, 1849, Annales des ponts et chaussées
– On Tolls and Transport Charges, 1849, Annales des ponts et chaussées
– De la législation actuelle des voies de transport; nécessite d’une réforme basée sur des principes rationnels, 1849, Journal des économistes
– De l’impôt payé aux maîtres de poste par les entrepreneurs de voitures publiques, 1851, Journal des économistes
– Rapport sur le projet de loi sur la police du roulage, adapté par la commission instituée par arrêté du ministre des travaux publics en date du 20 avril 1849, 1852, Annales des ponts et chaussées
– ‘Péage’, ‘Ponts et chaussées (Corps des)’, ‘Voies de communication’, ‘Routes et chemis’, ‘Eau’, 1852-3, entries in Coquelin, editor, Dictionnaire de l’économie politique
– De l’utilité et de sa mesure: de l’utilité publique, 1853, Journal des économistes
– Du monopole des chemins de fer, 1853, JdE
– Traité théorique et pratique de la conduite et de le distribution des eaux. 1854
– Decintrement des arches de pont au moyen de verrins, 1856, Annales des ponts et chaussées
– Titres scientifiques de M. J. Dupuit, 1857
– Des crises alimentaires et des moyens employés pour y remédier, 1859, JdE
– L’impôt du tabac progressif à rebours, 1859, JdE
– La liberté commerciale: Son principe et ses conséquences, 1860, Revue Européenne
– Effets de la liberté du commerce – lettre de M. Dupuit, 1860, JdE
– La liberté commerciale: Son principe et ses conséquences, 1861
– Du principe de propriété – le juste – l’utile, 1861, JdE
– Réponse à M. Dunoyer, 1861, JdE
– Études théoretiques et pratiques sur le mouvement des eaux dans les canaux découverts et à travers les terrains perméables, 1863
– Questions d’économie politique et de droit public par M. G. de Molinari, 1863, JdE
– Réglementation de la propriété souterraine et de l’industrie minérale, 1863, JdE
– L’économie politique est-elle une science ou n’est-elle qu’une étude?, 1863, JdE
– Response de M. Dupuit à M. Baudrillart, 1863, JdE
– Des causes qui influent sur la longueur de la vie moyenne des populations, 1865, JdE
– De la liberté de tester, 1865, JdE
– Traité de l’équilibre des routes et de la constructions des ponts en maçonnerie, 1870
– De l’utilité et de sa mesure: Écrits choisies et republiés par Mario de Bernardi, 1933