At the risk of some tediousness, perhaps, but thinking that afterwards the connection between the decoration and the architecture would be more clearly understood, the writer has given this general description of the Rotunda, in order that the visitor might immediately see what portion of the whole was essential and what not essential; what was “structural” and vital, in other words, and what not. It will have been observed that we have, on the outside, an octagon supporting a shallow dome, on which rests the lantern. Well within this is an octagonal arrangement of piers carrying a much steeper dome. Alcoves occupy the space between the inner and outer octagons. Between the two domes--the inner shell and the outer--is vacancy. The whole exterior--walls, dome, and lantern--the partitions back of the piers, and the connecting screens: all could be torn away and the inner dome still remain secure on its eight massive piers. [Illustration: COMMERCE. BY JOHN FLANAGAN.] The piers are constructed of brick, veneered with marble from Numidia in Africa, curiously mottled and in color a sort of dusky red. The high base on which the pier rests is sheathed with a chocolate brown variety of the familiar close-grained Tennessee marble. The height of the piers, including base and capital, is forty-four feet. The screens are built solidly of marble from Sienna, Italy, which encloses in its rich black veining almost every variety of yellow, from cream color to dark topaz. Like the piers, the screens are erected upon a Tennessee marble base, in this case, however, very much lower--four feet to the other’s eleven. The arcading of the screens is in two stories, the first of three and the second of seven arches. At the top of each screen the gallery is railed in by a heavy balustrade--still of the same Sienna marble--connected with which are two marble pedestals which bear bronze statues of illustrious men. The screens are alike on every side of the octagon but two, the west and the east--the former the entrance from the Staircase Hall, and the latter affording a way through to the east side of the building. In both instances, therefore, the central arch is accentuated by free standing columns. In the second story of the west screen, also, still another modification has been made in order to allow space for a large clock--the three middle arches giving place to a rich architectural setting ornamented with bronze statuary.