Eighteen hundred and eighty feet long, four hundred and sixty-four
wide, forty-eight to the cornice and seventy to the roof-tree, are
figures as familiar by this time to every living being in the United
States as pictures of the Main Building. At each corner a square tower
runs up to a level with the roof, and four more are clustered in the
centre of the edifice and rise to the height of a hundred and twenty
feet from a base of forty-eight feet square. These flank a central
dome one hundred and twenty feet square at base and springing on iron
trusses of delicate and graceful design to an apex ninety-six feet
above the pavement--the exact elevation of the interior of the old
Capitol rotunda. The transept, the intersection of which with the nave
forms this pavilion, is four hundred and sixteen feet long. On each
side of it is another of the same length and one hundred feet in
width, with aisles of forty-eight feet each. Longitudinally, the
divisions of the interior correspond with these transverse lines.
A nave one hundred and twenty feet wide and eighteen hundred and
thirty-two feet long--said to be unique for combined length and
width--is accompanied by two side avenues a hundred feet wide, and as
many aisles forty-eight feet wide. An exterior aisle twenty-four feet
wide, and as many high to a half-roof or clerestory, passes round the
whole building except where interrupted by the main entrances in the
centres of the sides and ends and a number of minor ones between.

The iron columns which support the central nave and transept are
forty-five feet high, the roof between rising to seventy. Those of
the side avenues and transepts are of the same height, with a
roof-elevation of sixty-five feet. The columns of the centre space
are seventy-two feet high. In all, the columns number six hundred
and seventy-two. They stand twenty-two feet apart upon foundations of