Although the purpose of this Handbook is to tell the principal facts about the Library as an institution, its chief use is likely to be that of a guide to the Central Building. The section about the Central Building is therefore given first place. Any visitor who cares to take the trouble, before beginning his tour of the Building, to read the brief historical sketch (on pages 63-73) will have a better understanding of the organization and work of the Library, and see the reasons for a number of things which might not otherwise be clear.
n Department, there is a card catalogue of all the books in this Department,--that is, in the Branches of the Library. The Room is open to the public, for the consultation of this catalogue, on week days from 9 a. m. to 5 p. m.
[Illustration: BASE OF FLAGPOLE]
=Technology Division.= Following the corridor leading to the north from the main entrance, there is, on the right, the room of the Technology Division (No. 115), devoted to applied science and engineering. The collection of books in this Division, or under its control, numbers about 65,000. In this room, as in all the special reading rooms, with a few exceptions, books are on open shelves for the free access of readers and students.
=Patents Room= (No. 121). At the end of the corridor parallel to 42nd Street, is the Patents Room, a part of the Technology Division. It is open from 9 a. m. to 6 p. m. on week days, and is closed on Sundays. Patents may be consulted evenings and Sundays by arrangement with the technology librarian, Room