STUDIES OlSr MUSEUMS AND KINDRED INSTITUTIONS. 47 \) 



injurious to the buildincr itself, as, for example, to the mosaic floors, 

 which already have sufl'ered at various places." If the engines must 

 stand in the house itself, they should be isolated, as in Columbia Uni- 

 versity, already mentioned, although this would be more difficult in 

 the swamp3^ ground of Chicago than in the rocky region of Columl)ia 

 University. Eight electric elevators serve for the incessant demands 

 of visitors. The stairs are but little used. 



The problem of a fireproof building has here been perfectly solved. 

 In Chicago, as well as elsewhere in America, it is customary, when 

 constructing large buildings, to first of all erect a steel framework or 

 skeleton, which runs from top to bottom and across the building (see 

 fig. 58), and into this frame are set the walls of brick or stone (as with 

 us a framework of wood is filled out with stones and clay) and the 

 building can then be carried on from above downward, instead of the 

 opposite, since each story is independent from the others and rests on 

 its own foundation. In the public library this has been avoided, for 

 if in such buildings stores of combustible goods begin to burn, the 

 steel beams bend and the whole structure falls together like a house 

 of cards. In the public library the steel construction rests upon the 

 walls of the building, not the reverse, and steel supporting columns 

 are entireh'^ avoided. The great spans between the walls are mostl}' 

 bridged over with box girders, but also with plate and lattice girders 

 between which are iron beams. The span of the box girders is 66 

 feet. Fig. 59 gives a representation of the steel construction of the 

 floor. The spaces between the floor beams are filled in with large 

 porous terra-cotta blocks. The steel beams and supporting columns 

 are also encased with terra cotta, which makes them absolutely fire- 

 proof. The floors are laid in cement, upon which are set marble 

 mosaics, glazed tile, or parquetry, the last, however, only in offices 

 and workrooms, where it is covered with corcacin, to the value of 

 about $3,500. The gang plates at the book stacks are made of hard 

 glass or tile. The walls are wainscoted or lined with marble. Window 

 casings and sashes,- as well as book stacks, are of iron (costing about 

 $30,000), the other furniture (costing about $66,000) and the doors 

 are of wood. On the latticework, doors, and elsewhere much rich 

 bronze work is used. For important documents and rarities special 

 fireproof vaults with iron cases are provided, as shown in fig. 60. 



On account of the swamp}' foundation of Chicago the librar}- rests 

 upon 2,400 piles, each 55 feet long and of 12 inches diameter, that are 

 driven to an average depth of 75 feet below the level of the street 



« Whether or not this is to be ascribed to the strong shaking alone I will not state 

 I^ositively. It is also possible there is some fanlt with the cement base. In any 

 event, however, tliese tremors can do no good to tlie building. I even see that they 

 endanger its permanence, and that ultimately an engine room will have to be built 

 outside. 



