488 



REPORT OF NATIOISTAL MUSEUM, 1903. 



pers). Repositories are liere provided for folios of the largest size; 

 the books lie upon rollers and slide from right to left, so that any 

 iiijui'v to the hindino- is avoided. This is a very excellent although 

 costly ap[)aratus, especially used in case of valua))le works upon art, 

 in which the library is not poor, and which aie nuich used. The wires 

 for electric lights run inside of the hook stacks in protected conduits 

 which above are ))i'<)ught out into the aisles and bear the incandescent 

 lamps (see figs. 66 to 68). 



Fig. 67. — Chicago Public Library. Closable alcove. 



Elevators driven by electric power carr}^ the books between the 

 repositories, up and down, and into the reading rooms of the third 

 story. On the southwest side of the ground floor are the rooms from 

 which books are sent out to the 65 delivery stations of the city. The 

 book stacks are connected with these rooms by pneumatic tubes of 3 

 inches diameter, speaking tubes, and telephone, as well as by two 

 service elevators. 



The telephone system of the liV)rary is very extensive; 24 rooms can 

 be connected with each other, and the head bureaus also, with the city 

 system, through a connnon switch board placed in the central station 

 of the building, which must in every case be called up. There are 



