After the death of Augustin Fresnel in 1827, his brother Léonor (1790–1869) took his place as secretary of the Lighthouse Commission. He set up the Lighthouse Service to administer the network, which was growing rapidly. Most of France's 150 major lighthouses were built during the nineteenth century. In Paris, the Lighthouse Service was originally installed in a workshop at the Quai de Billy (1848), and then in a warehouse on the hill of Chaillot (1869). There, engineers tested the application of new inventions, such as electricity. They also carried out the thankless administrative tasks without which no network can function – archiving decisions, managing staff and materials, and drafting instructions and regulations. Paris was not only the administrative capital for the country's lighthouses, it was also the industrial nerve centre. In 1838, Henry-Lepaute (1800–1885) opened an optics workshop in the Rue Saint-Honoré. In 1852, Louis Sautter (1825–1912) took over the company handed down by Soleil, Fresnel's optics expert. A third businessman appeared several years later: the firm Barbier et Fenestre, which later became Barbier, Bénard & Turenne (BBT). These three firms – Sautter, Lepaute and BBT – divided up the French market, both domestically and in the colonies. They also secured significant contracts in the US and in the Ottoman Empire. At the various universal expositions, visitors were treated to the sight of the large lenses produced by the firms, and sometimes actual lighthouses made out of metal. Along with roads, canals or railways, lighthouses became a major technical network, administered from Paris by the Minister of Public Works.
