THE BUILDING FOR THE LIBRARY OF CONGRESS. 631 



stacks, as above described, a slender, rolled steel framework of continu- 

 ous columns and horizontal deck members was introduced, dividing the 

 stack into nine stories of 7 feet each. The decks are covered with white 

 marble slabs and contain narrow openings in front of the shelf ranges 

 for communication, admission of light, and circulation of air. In each 

 story on either side of every column a simple vertical cast-iron wing is 

 attached, having the necessary teeth and lugs to receive the shelves 

 and permit of their ready adjustment to any interval desired. The 

 shelf is of a gridiron form, being a set of parallel bars of n section, 

 forming an extremely stiff and smooth shelf, capable of receiving any- 

 thing that any shelf may be called upon to carry while its weight does 

 not exceed that of white pine wood. The shelves may all be removed 

 from any bay or series of bays on a deck to make a passageway or 

 insert any convenient piece of furniture, such as a card catalogue, desk, 

 or cabinet of any kind. The shelf length is uniformly 38 inches in all 

 the stacks and the shelves are therefore quite generally interchange- 

 able. Thus, by indefinite multiplication of the few simple elements 

 described, a stack of almost any required dimensions and capacity may 

 be constructed. Proper anchorage of the horizontal deck bars in the 

 surrounding walls is requisite for lateral stability of the loaded stack, 

 and some other constructive details must be observed, but it is a sim- 

 ple thing to make a stack of twenty or more stories or tiers in height 

 and of almost any other dimensions. 



The book carrier is a pair of parallel, endless chains, running in a 

 vertical shaft in the middle of the stack; thence in a horizontal duct 

 in the cellar to a point below the central desk of the reading room, 

 where it turns upward and ascends vertically to the delivery outlet at 

 the desk. A series of equidistant book trays, eighteen in number, are 

 suspended between the chains. The machine runs continuously and 

 automatically takes on and delivers books of the size of a quarto or 

 less at its reading room terminal and at each of the stack stories. The 

 speed of the carrier is about 100 feet per minute. 



The pneumatic message tube is also convenient as a speaking tube. 



The great rotunda or public reading room of the building, the main 

 staircase hall or foyer, the private reading rooms for the members of 

 Congress, the Librarian's ofilice, the corridors commuuicating with 

 these, and the exhibition halls as well as many portions of the exterior 

 walls, especially the west main pavilion, have received a good degree 

 of artistic treatment and embellishment, but all within strict architec- 

 tural requirements. Some forty sculptors and mural painters, about 

 equally divided in numbers, furnished the principal works of art under 

 the architects' supervision and direction. Many appropriate quotations 

 and names are inscribed on the walls in the architectural tablets, 

 freizes and jpanels, adding to the general impressiveness and interest 

 of the building. 



In all ways and from all points of view the library building is emi- 

 nently instructive as an example of good design, good appointment for 



