The Capitol Dome - html version

THE CAPITOL DOME

The dome of the United States Capitol is undoubtedly the nation's most famous landmark, recognized throughout the world as a symbol of the American people and their government. It was designed and constructed between 1854 and 1865 by Architect of the Capitol Thomas U. Walter and Superintendents of Construction Montgomery C. Meigs and William B. Franklin.

[image: 1846 photograph of the first Capitol Dome. Photo: Library of Congress]

The present cast-iron dome is actually the building's second. The Capitol's first dome, made of brick and wood covered with copper, was finished in 1824 by Charles Bulfinch. In the 1850s, as the House and Senate wings were being added (doubling the building's length), it was considered too small for the enlarged Capitol. It was also a fire hazard and was in constant need of repair. In 1855 Congress decided to replace the old dome with a new one made of cast iron.

Why Iron? Iron was used to build the dome because it could be mass produced, was relatively cheap, and was light in weight compared to masonry. Thus the new dome could be added on top of the old Rotunda walls without shoring up the foundations. It could also be quickly built and would cost far less than a marble dome of similar design. Further, iron columns could be cast hollow not only reducing weight but also allowing some to serve as chimneys or downspouts.

Foundries in Virginia, Maryland, New Jersey, and New York supplied the iron for the lower parts of the dome. After a contract was signed in 1860, all the iron was cast, delivered, and installed by the Janes, Fowler, Kirtland Company of New York for 7 cents per pound.

The Mechanics of Construction. After the old dome was removed, a temporary roof was built over the Rotunda and a wooden scaffold was erected on the Rotunda floor. A steam engine mounted on the Capitol's roof and fed by wood from the old dome powered the ropes, wires, and pulleys that lifted the ironwork into place.

[image: The cast-iron dome under construction.]

Brackets, columns, ribs, girders, and plates rose higher and higher and were bolted together as construction continued steadily over the next decade, despite the outbreak of the Civil War.

Outer and Inner Domes. The Capitol dome actually consists of two domes. The outer dome was scaled to the size of the enlarged building. The inner dome was designed in accordance with the proportions of the Rotunda. This use of inner and outer "shells" was inspired by the Pantheon in Paris.

The Statue of Freedom. The outer dome is crowned by a 19 1/2-foot female figure representing Freedom. It was commissioned in 1856 from Thomas Crawford, an American sculptor working in Rome, and cast in bronze by Clark Mills at a local foundry On December 2, 1863, the last of the statue's five sections was put in place on top of the dome amid a great celebration.

THE ROTUNDA

The Rotunda was constructed between 1818 and 1824. Located in the center of the Capitol, it has been the scene of such diverse ceremonial events as a reception for the Marquis de Lafayette, the lying in state of Henry Clay and Abraham Lincoln, and the 1985 inauguration of President Ronald Reagan.

The Rotunda Frieze. The frescoed frieze in the belt just below the dome's windows was painted to give the illusion of a sculpted relief. The scenes designed by Constantino Brumidi and, later, Allyn Cox trace America's history from the landing of Columbus to the birth of aviation.

[image: Brumidi's canopy fresco, completed in 1865.]

Apotheosis of George Washington. In the central group of Constantino Brumidi's fresco, George Washington rises to the heavens in glory flanked by female figures representing Liberty and Victory/Fame and by thirteen maidens symbolizing the original states.

Six allegorical groups line the perimeter:

War-Armed Freedom and the eagle defeat Tyranny and Kingly Power.
Science-Minerva teaches Benjamin Franklin, Robert Fulton, and Samuel F.B. Morse
Marine-Neptune holds his trident and Venus holds the transatlantic cable, which was being laid at the time the fresco was painted.
Commerce-Mercury hands a bag of money to Robert Morris, financier of the American Revolution.
Mechanics-Vulcan works at the anvil and forge, producing a cannon and a steam engine.
Agriculture-Ceres sits on the McCormick Reaper, accompanied by America in a red liberty cap and Flora picking flowers.

HIGHLIGHTS

The balcony at the base of the tholos is approximately 210 feet above the Capitol's east front plaza. It offers a spectacular view of the capitol city as well as the neighboring states of Virginia and Maryland.

The view of the Rotunda canopy from the balcony at the top of the inner dome shows Brumidi's skill in painting figures that are imposing from this vantage point as well as from the Rotunda floor 152 feet below. The Apotheosis of Washington (1865 ) is a fresco that covers 4,664 square feet.

This viewing area overlooking the Rotunda and its many works of art is about 85 feet above the floor. Much of the window glass was made in England and marketed in America by Theodore Roosevelt, Sr. Above this point, the stairway leads between the inner and outer shells of the dome.

The space under the skirt of the dome offers a view of the original sandstone walls built ca. 1820-1822 for the first dome. Embedded at the top of this wall are paired iron brackets that support the 36 columns of the dome's lower colonnade. The number of columns was selected to simplify their placement around the 360 degrees of a circle. The roof areas to the left of the walkway are the only original 1820s roofs remaining at the Capitol. The stairways that lead to the top of the dome were installed during construction.

ELEMENTS OF THE DOME

[image: Composite view of Thomas U. Walter's 1859 elevation and cross section drawings of the Dome.]

DOME FACTS