50 UISriTED STATES NATIONAL MUSEUM 



tion of the auditorium in the ground story. In the corridor, however, 

 steel beams are used, having both bearings on walls except over the 

 openings to the stair towers where a lintel support is provided. The 

 construction for the galleries is the same except that in the screened 

 interspaces the inner ends of the beams are sustained by plate girders 

 2 feet 2 inches deep by 12 inches wide, spanning between the piers. 

 In the first story the beams are 15 inches deep and in the other stories 

 12 inches deep, the foundation floor construction in all stories being 

 of terra cotta blocks. 



The finished first floor of the rotunda and corridor consists of 

 roseal Tennessee marble, with border lines and inserts of green serpen- 

 tine and cipoUino. A star-shaped center motive of the roseal has a 

 circular border of bands of the same materials. There is a continuous 

 border of the three stones around the rotunda, passing just inside 

 the bases of the piers ; a border panel occurs between the bases of the 

 columns, and there are border lines through the corridor with cipollino 

 inserts at each angle of the turns. The floors of the galleries are of 

 pink Tennessee marble with borders of Sienna marble. All of the 

 floor tiles have a fine sand-rubbed surface. 



The wall bases, plinths for door trims, etc., match the floor material 

 in the several stories and consist, therefore, of the roseal marble in 

 the first story and of the pink marble elsewhere, finished with a high 

 putty polish. Their height in the first story is 22 inches, in the 

 second story 12 inches, in the third story 9 inches, and in the fourth 

 story, where they are 2| inches thick and have a molded top, 12 inches. 



Main entrance gates and vestibule. — The south or main entrance, 

 leading into the pavilion from the portico, comprehends a single 

 large opening in the granite front, 12 feet 9 inches wide by 25 feet 

 9 inches high, in which, however, the clear space is reduced by a tran- 

 som above and 9-inch cast-iron frames at the sides to a width of 

 11 feet 3 inches and a height of 17 feet 6 inches. This opening is 

 provided with iron gates made in two leaves, which slide on an over- 

 head track supported on a 15-inch channel and a floor guide rail into 

 a pocket in each jamb. The gates are framed by bars of wrought 

 iron, but all detail and ornamentation are of cast iron, and the finish 

 is the same on both sides. Each leaf is divided into three large cir- 

 cular, square-framed, rosette panels with smaller panels between, the 

 entire composition being surrounded with a leaf motive border. The 

 transom bar or band is of a fret design and the transom, which is of 

 a rosette-centered scroll design, is bordered with a leaf band similar 

 to that in the gates. The transom bar conceals the track and track 

 hanger for the gates, which weigh approximately 11,488 pounds and 

 are operated by hydraulic power. 



Immediately within the gates is a vestibule of bronze, marble and 

 plate glass construction, mostly confined between the end walls of the 



