NATURAL HISTORY BUILDING 111 



lineal feet; and of 18-inch shelving, 1,989 lineal feet; a total of 

 26,868^ lineal and 28,516 square feet of shelf surface. While the 

 present shelf space seems quite fully occupied, it is improbable that 

 the capacity of the compartment will be overtaxed for some years. 

 The load capacity of the shelves, as determined by actual tests, is 

 about 155 pounds to the square foot, which is sufficiently in excess 

 of any weight they will be called upon to carry to leave a good 

 margin of safety. 



For the lighting of the alcoholic compartment, which is wholly 

 dependent upon artificial means, a simple but effective electric 

 system has been provided. The wires are run in ^-inch loricated 

 electro ducts or pipes, which are carried, uncovered, about the room, 

 connecting the switches with the receptacle outlets. The outlets 

 are mostly dropped a short distance from the ceiling in both stories, 

 and are supplied with Benjamin two-light tungsten clusters, with 

 the idea that, generally, only one lamp will be used directly in each 

 cluster, leaving the other socket for an attachment plug with ex- 

 tension cord and lamp which can be carried or moved about the 

 shelving. The distribution of the outlets is through the aisles along 

 the outer and inner walls, and in the passageways between the 

 stacks, there being one outlet in each of the latter. 



The lighting is controlled separately in the two stories, and also 

 separately for each bay or length unit. The switches are all con- 

 veniently placed on the inner surface of the outer walls. For the 

 lower floor there is a switch on the entrance side of each door, which 

 controls the lights in the corresponding bay. On the second floor 

 there is, in addition to the general system, a patrol system, consist- 

 ing of one lamp in each bay along the outer corridor, the switches 

 for which are directly at the top of the stairs and elevators. The 

 object of the patrol system is to furnish some light as soon as one 

 reaches the upper floor, which has not the advantage of the door 

 openings possessed by the lower floor. 



FIRST STORY AND SOUTH PAVILION 



South pavilion and rotunda. — While the first story may be reached 

 as readily by means of the stairs and elevators leading from the north 

 entrance in the ground story, the logical approach is from the south 

 or park side by way of the large opening within the portico at the 

 head of the double flight of broad granite steps. Passing through 

 the small bronze, marble and glass vestibule inside of the heavy iron 

 grilles at this, the main, entrance, one finds himself on the main floor 

 of the south pavilion and rotunda, which is virtually the center of 

 communication for all parts of the building. As described elsewhere, 

 the space enclosed in this prominent architectural feature is of large 



