NATURAL HISTORY BUILDING ' 57 



Vestibule and lobby doors. — All main doors of the vestibule and 

 lobby inside of the grilles are identical in material and design, con- 

 sisting mainly of plate glass set in molded bronze, of which the 

 frames, trims, push bars, etc., are also constructed. They are in 

 pairs, occupying the three outer and three inner openings, and the 

 two entrances to the ranges at the ends of the lobby. Although the 

 actual size of each pair of doors is but 9 feet 5 inches high by 5 feet 

 wide, all are located in openings of a much larger area. In all cases, 

 except the two range openings which are 9 feet wide, the width 

 between the finished jambs is 8 feet 6 inches, but, while the openings 

 into the lobby from the vestibule and ranges are 13 feet and 13 

 feet 3 inches high, respectively, those into the vestibule from the 

 outside are 15 feet 4f inches high. The spaces resulting around the 

 actual door openings are occupied by glazed screens, providing lights 

 on either side, and a transom above divided into three lights by 

 the continuation of the mullions framing the doors. The outside 

 vestibule screens are placed 6 inches from the inside face of the 

 stone jambs and are separated from the grilles by 11-| inches. Those 

 of the inside of the vestibule are built flush with the inside face of 

 the wall, as are also the range screens with the range side of the 

 openings. The glass is left clear in the doors and screens of the 

 vestibule, but is ground on one side in those leading into the ranges. 

 All doors are provided with checking spring hinges and stops, and 

 have top and bottom bolts and Yale paracentric locks. The four 

 doors to small rooms off the lobby are of cabinet oak and not glazed. 



PARTITION WALLS AND INTERIOR FINISH 



LIGHT WELLS AND CEILING LIGHTS 



The light wells which occur over the middle section of the main 

 halls in the three wings pierce the second, third and attic stories. 

 They are all of the same design, entirely walled in, and have a ceil- 

 ing light about 18 inches below the level of the attic floor. Their 

 position and extent are indicated by the arrangement of the rows 

 of piers in the first story, by which their walls are mainly supported. 

 In width they are spaced equidistant between the outer and court 

 walls, but in each case the pavilion wall forms the enclosing wall at 

 one end, while the far wall is distant from the end of the wing 48 

 feet 6f inches in the east and west wings, and 36 feet W\ inches in 

 the north wing. The width is identical in all the wells, being 49 

 feet 4-^ inches between the finished wall surfaces, but while in the 

 east and west wings the length is 167 feet \\ inches, in the north 

 wing it is 6^ inches greater. The height of the Avells from the level 

 of the first story ceiling to the lower side of the ceiling light is 34 

 feet 8 inches. 



