a. Construction was a laborious and time-consuming process: the sandstone used for the building had to be ferried on boats from the quarries at Aquia, Virginia; workers had to be induced to leave their homes to come to the relative wilderness of Capitol Hill; and funding was inadequate. Because of Thornton's inexperience, the initial work progressed under the direction of three architects in succession. Stephen H. Hallet and George Hadfield were dismissed because of inappropriate design changes they tried to impose; James Hoban, winner of the competition for the President's House, was placed in charge and saw to the completion of the north wing for the first session of Congres. Construction resumed under Benjamin Henry Latrobe who completed the south and north wings. By 1813, Latrobe, with his job done, departed with the wings connected by a temporary wooden passageway. On August 24, 1814, British troops set fire to the building during the War of 1812. A rainstorm prevented its complete destruction and Latrobe returned to Washington in 1815 to make repairs. He took this opportunity to make changes to the building's interior design and to introduce new materials, such as marble. Latrobe, however, resigned his post in November of 1817 because of construction delays and increasing costs. Charles Bulfinch, a Boston architect, was appointed Latrobe's successor in January of 1818. Continuing the restoration, he was able to make the chambers of the Senate and House, as well as the Supreme Court, ready for use by 1819.