Declaration of Independence with the concept of liberty. Bartholdi interested his friend and mentor, architect Eugène Viollet-le-Duc, in the project. As chief engineer, Viollet-le-Duc designed a brick pier within the statue, to which the skin would be anchored. After consultations with the metalwork foundry Gaget, Gauthier & Co., Viollet-le-Duc chose the metal which would be used for the skin, copper sheets, and the method used to shape it, repoussé, in which the sheets were heated and then struck with wooden hammers. An advantage of this choice was that the entire statue would be light for its volume, as the copper need be only thick. Bartholdi had decided on a height of just over for the statue, double that of Italy's Sancarlone and the German statue of Arminius, both made with the same method. Announcement and early work By 1875, France was enjoying improved political stability and a recovering postwar economy. Growing interest in the upcoming Centennial Exposition in Philadelphia led Laboulaye to decide it was time to seek public support. In September 1875, he announced the project and the formation of the Franco-American Union as its fundraising arm. With the announcement, the statue was given a name, Liberty Enlightening the World. The French would finance the statue; Americans would be expected to pay for the pedestal. The announcement provoked a generally favorable reaction in France, though many Frenchmen resented the United States for not coming to their aid during the war with Prussia. French monarchists opposed the statue, if for no other reason than it was proposed by the liberal Laboulaye, who had recently been elected a senator for life. Laboulaye arranged events designed to appeal to the rich and powerful, including a special performance at the Paris Opera on April 25, 1876, that featured a new cantata by composer Charles Gounod. The piece was titled La Liberté éclairant le monde, the French version of the statue's announced name. Initially focused on the elites, the Union was successful in raising funds from across French society. Schoolchildren and ordinary citizens gave, as did 181 French municipalities. Laboulaye's political allies supported the call, as did descendants of the French contingent in the American Revolutionary War. Less idealistically, contributions came from those who hoped for American support in the French attempt to build the Panama Canal. The copper may have come from multiple sources and some of it is said to have come