Originally, the university planned to use the Tower as a library space, using a dumbwaiter system to carry books from the upper floors to the students requesting them in the circulation room on a lower floor. Library employees were stationed on every other floor; students filled out paper book-request slips, which were sent upstairs by a pneumatic tube. The books were sent down to the students using an 18-story dumbwaiter. This proved ineffective, and the dumbwaiter is no longer used for that purpose. The building now mainly contains administrative offices, though it does still house a three-floor life sciences library and the Miriam Lutcher Stark Library of early and significant editions of English Romanticist works. Two separate sets of elevators serve the building; one in the front, one in back. In the floors above the stacks and below a few top-floor offices, several floors contain the university herbarium (Plant Resources Center). U.S. Census data are compiled and analyzed on some of these floors. Lastly, two secure elevators provide access to all 27 floors of the Tower while an elevator on the 27th floor provides access to the 28th-floor Observation Deck. There is also a book elevator in the stacks that serves floors 2 through 17.