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Look Around You:
The Basics of the Building:

This room was constructed under the south portico between 1840 and 1842. When you entered, you passed through a doorway cut through the outer wall of the Patent Office Building. The wall is 6 foot 4 inches thick at this level.

Plaster has been removed from the ceiling to reveal the brick vaulting system designed in 1836 by architect Robert Mills. He used a new quick-drying hydraulic cement to hold the bricks in place. This same method of vaulted construction was used throughout much of the building.

Gray granite, quarried in Maryland, was used for the base of the building and for three sides of the courtyard. In the doorway passage and just below the vaulting, you can see the coarse tan sandstone -- quarried in Aquia Creek, Virginia -- that was used for the exterior of the building's earliest wing. (The same sandstone was used to build the White House and original wing of the US Capitol.) The white marble employed for the other three wings was quarried in Maryland.
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