42 UNITED STATES NATIONAL MUSEUM 



thrust against the intervening screen walls, but the stress is carried 

 by four large penetrations. The tile construction begins 6 feet 9 

 inches above the finished ground floor level, and the spring line of 

 the dome proper 3 inches higher. This domical ceiling has at the 

 center a circular eye or ring of ornamental terra cotta, 26 feet 4 

 inches in diameter to the center of a decorative leaf band, project- 

 ing sufficiently below the ceiling to allow for the placing of electric 

 ■lights around the inner and outer edges, hidden from sight behind 

 the molded members. All finished Guastavino tile has a highly 

 glazed ribbed surface and all, with the exception of several courses 

 around the eye, is laid herringbone. The terra cotta matches the tile 

 in color and finish, having a glazed surface, and has the leaf bands 

 and other ornamentation picked out in color. Besides giving a finish 

 for the auditorium, the dome actually supports the floor of the ro- 

 tunda above, dwarf walls intervening in the space between the two, 

 which at the highest point of the dome is but 18 inches. The dome 

 is designed to sustain a imiformly distributed load of 500 pounds to a 

 square foot. The alcove of the speakers' platform is also finished 

 with Guastavino tile, beginning at the same level as in the body of 

 the auditorium. 



Besides the four large elliptical penetrations intersecting the dome 

 from the sides of the auditorium, and having ornamented terra cotta 

 arches against the walls, there are also four smaller penetrations on 

 the diagonal axes over the small niches and corresponding entrance 

 doors. The soffits of the east, west and north arches are 2 feet 2 

 inches wide and decorated with a fret motive enclosed in a sunken 

 bordered panel, while the soffit of the arch over the speakers' plat- 

 form is 3 feet 6 inches wide and decorated with rosette-centered 

 panels. The crown of all four of these arches is 15 feet 4 inches 

 above the gTade of the finished ground floor, and the arch ring in all 

 cases is 9 inches wide and decorated with a sunken panel and leaf 

 motive. A circular vent register opening is provided in the soffit 

 of each of the large penetrations. 



Between the base and the tile and terra cotta work the walls are 

 plastered and finished with a molded cap which carries level around 

 the room except across the niches where the cap is omitted. A 

 3-inch sub-base of terrazzo extends around the entire room. The 

 base, of Keene's cement, is 15 inches high in the alcove at the south, 

 and continues of the same dimension on a line in front of the plat- 

 form up to the large niches on either side of the room. In the back 

 of these niches its top line is stepped toward the rear of the room 

 to keep above the level of the inclined floor, finally finishing with a 

 height of 9 inches, or 12 inches above the floor, in the back of the 

 auditorium. The reveals of the plastered door openings are refined 

 by shallow panels. 



