120 UNITED STATES NATIONAL MUSEUM 



abdut 3f inches is presented by each of the side walls adjoining the 

 ranges. In the east and west wings there is naturally but one such 

 offset, which occurs about 64 feet from the outer end of the wing and 

 reduces its width by the amount of the projection over the remain- 

 ing distance of about 152 feet to the wall of the rotunda. In the 

 north wing there are two offsets, one on each side, at a distance of 

 about 70 feet from the outer end, or at the juncture of its court 

 wall with those of the ranges, and the reduction in the width of 

 the inner part of this wing is double that in the other wings. In 

 calculating the floor area of the wing's allowance has also to be 

 made for the piercings of the light wells above the main story. 



The ranges furnish identical measurements in the ground, first and 

 second stories in which the width is uniformly 54 feet 2 inches, and 

 the total length of each range through the middle 316 feet 10 inches. 

 In the third story the width is 51 feet 10 inches, and the length 314 

 feet 6 inches. 



The south pavilion measures 111 feet 7 inches between its enclosing 

 walls on both main axes, and 122 feet 1 inch on the diagonal axes, 

 while the dimensions of the rotunda are 81 feet 6 inches on the main 

 axes, measured between the screens, and 83 feet 5^ inches on the 

 diagonal axes, measured between the great piers. In determining 

 the total area of the main floor of the pavilion only the space occupied 

 by the piers was excluded. The corridor back of the piers and screens 

 is 12 feet 4f inches wide, and the same dimensions are repeated in 

 the several galleries, but the extent of the third or upper gallery is 

 increased by the open space, 48 feet 2 inches long by 19 feet 2^ inches 

 wide, adjoining the large semicircular window on the south. 



In computing the amount of space allotted to different purposes, 

 tlie results of which are shown in the second and third tables which 

 follow, the entire available floor area of the building has been ac- 

 counted for. The exhibition space as given is clear of all obstruc- 

 tions other than the piers and screens, and the dimensions recorded 

 for all parts of the south pavilion are wholly in the clear between 

 walls. In the ground and third stories of the wings and ranges gen- 

 erally, however, the simple partition walls have been proportioned be- 

 tween the different assignments and included in their measurements, 

 as have also the corridors which, owing to their width, are to a large 

 extent available and already partly used for storage purposes. The 

 spaces occupied by the stair wells and elevator shafts have naturally 

 been repeated for each of the stories traversed, but in the aggregate 

 their extent is relatively small for so large a building. The principal 

 piercings occur in connection with the northern and the tower stairs. 

 The former are practically square, measuring with the landings 22 

 feet 3^ inches by 22 feet 5f inches, but the latter are elongate and 13 

 feet 10^ inches wide by 35 feet 8^ inches long. 



