28 UNITED STATES NATIONAL MUSEUM 



The granite work of the approach is supported and backed by 

 brick masonry, consisting of heavy piers, walls and arches resting 

 on concrete footings. Extending in front of the ground story pro- 

 jection of the pavilion, and therefore partly under the portico and 

 partly under the upper run of steps, is an arched passageway, 12 

 feet 3 inches wide, faced with white glazed brick and having granite 

 trimmings, which serves to connect the area driveway. On its north 

 side is an entrance into the ground story of the building, and on the 

 opposite side a door opening under the approach. The south wall of 

 this passageway in conjunction with the curved granite walls under 

 the ends of the platform surround the foundation construction, and 

 within this enclosure a considerable space, measuring 134 feet in 

 greatest length by 21 feet in greatest width, is available as a vault 

 for storage purposes. 



OUTER WALLS OF THE WINGS AND RANGES 



The total height of the stone work composing the south and end 

 faces of the east and west wings is 82 feet 1| inches, made up of the 

 three kinds of granite in the following proportions, namely, Milford 

 granite, 23 feet 3 inches ; Bethel granite, 43 feet 5 inches, and Mount 

 Airy granite, 15 feet 5^ inches. Of the Milford granite 3 inches are 

 below grade, and 3 feet 3 inches are below the ground floor level. 

 The Bethel granite begins at the first floor level and extends 11 inches 

 above the third floor level ; while the Mount Airy granite reaches 



4 feet 4J inches above the third story ceiling. The ranges have the 

 same extent of Milford and Bethel granite, but in the third story 

 the use of Mount Airy granite is restricted to a parapet wall and the 

 framing of the dormer window openings. 



The height from floor line to floor line in both the wings and ranges 

 is 20 feet for the ground story, 21 feet 6 inches for the first story, 

 and 21 feet for the second story, while the height from the floor line 

 to the ceiling of the third story is 12 feet, making a total of 74 feet 

 6 inches, or 7 feet 7^ inches less than the entire height of the stone 

 work in the wings. 



Ground story. — The base course consists of large stones having a 

 uniform height of 5 feet 7| inches and exposed to the extent of about 



5 feet 4| inches. The top of this course forms the sill line for all 

 ground story windows, which line is 2 feet 4^ inches above the finished 

 floor level of the interior, except in those parts of the story where, 

 as elsewhere explained, the height of that level has been increased 

 by 3 inches. Between the base course and the water table course there 

 are six regular horizontal courses, the lower being 1 foot 10 inches 

 thick, the four following alternating 2 feet 2^ inches and 2 feet 9|- 

 inches, and the upper 2 feet 6 inches. Seven voussoirs enter into the 

 composition of each window arch, and between them at the middle of 

 the piers, forming a unit of what is. above referred to as the sixth 



