View of the Latrobe-Hoban segmental vault under theNorth Portico. The course of cut stone that formed the outer edge of Latrobe’s original vaulted bridge still reads clearly as a broad rectilinear rib arcing gently downward (northward) toward the rear of the space. Both the Latrobe (left-west) and Hoban (right-east) brick vaulting on either side is composed of three courses of stone at the point where it meets the rear wall, followed by neat brick courses laid in English bond, presumably returning all the way back to the residence. In total, this vault has supported the North Portico for nearly two centuries.