Henry Darcy and His Law

One Page Biography

by
Glenn Brown
10/30/01 (revised 9/03/03)

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Henry Darcy Main


Henry Philibert Gaspard Darcy was born June 10, 1803 in Dijon, France. His father, Jacques Lazare Gaspard a minor civil servant, was the Collector of the Registry (tax collector). Darcy's younger brother, Hugues, became a noted Prefect and civil servant. His father died in 1817 when Henry was 14, and his mother Agathe Angelique Serdet rose to the task of insuring his and his brother's education. She had only a small city pension to live on, but she was able to borrow money for tutors and obtained city scholarships for her sons to attend college.

In 1821, at the age 18 Darcy entered L'Ecole Polytechnique (Polytechnic School), Paris. Two years later Henry was admitted to L'Ecole des Ponts et Chaussee's (School of Bridges and Roads), Paris. The school was a part of the Imperial Corps des Ponts et Chaussee's (Corps of Bridges and Roads. After graduation, he was eventually assigned by the Corps to a position in Dijon. In 1828 he married Henriette Carey. She was an English native from the Isle of Guernesey whose family was living in Dijon. They remained together until his death, but had no children.

In 1828, Darcy was assigned to a deep well drilling project that found water but could not provide an adequate supply for the town. However, soon after the disappointment of the well, and under his own initiative, Henry set out to provide a clean, dependable water supply to the city from more conventional surface water sources. That effort eventually produced a system that delivered 8 m3/min from the Rosoir Spring through 12.7 km of covered aqueduct to an enclosed 5,700 m3 reservoir located near the Porte Guillaume and another reservoir at Montmusard. Pressurized distribution lines totaling 28,000 m were laid in underground galleries and provided water to major buildings and 142 public street hydrants spaced 100 m apart throughout the city. The entire system was enclosed and gravity driven, thus it required no pumps or filters. Darcy followed that project with numerous other civil works in and near Dijon including roadways, bridges, sewers and a railroad tunnel. He also was very active in the Dijon City Government.

By 1848 Darcy was Chief Engineer for the Department of Côte-d'Or, but due to political pressures, he was forced to leave Dijon. He was however soon appointed to the higher position of Chief Director for Water and Pavements, Paris. In Paris he carried out significant research on the flow and friction losses in pipes, which forms the basis for the Darcy-Weisbach equation for pipe flow. He also created an improved design for the Pitot tube and was the first researcher who postulated the existence of the boundary layer in fluid flow.

In 1855 due to failing health, he resigned from normal duties but was allowed to return to Dijon to carry out research of his own interest. In 1855 and 1856 he conducted column experiments that established Darcy's law for flow in sands. Since his time Darcy's Law has been generalized by many writers to allow for differential solutions, vector analysis, unsaturated flow and multiphase flow. Likewise, the equation's theoretical basis and applicability in several fields has been well defined.

Unexpectedly, on January 3, 1858, Darcy died of pneumonia while on a trip to Paris. He is buried in Dijon, next to his wife and mother.