The official opening of Houghton Library, recently completed annex to Widener which will be able to house 250,000 of the most valuable books and manuscripts in the University collection, has been set for Saturday evening, February 28, announced Keyes D. Metcalf, director of the entire University Library.

Opening ceremonies will be restricted to a small number of people because much of the limited space in the building is already taken up by 100,000 rare books. They will be followed by a reception for members of the Faculty on Sunday afternoon, and then the Library will be opened for public use on Monday morning.

Although work has been proceeding on the newly completed project for the past year and a half, it was not until last month that President Conant announced the name of the donor, Arthur A. Houghton '29, president of Stueben Glass Incorporated.

In the six floors of the library, three of which are underground, there is not only room for storage of a quarter of a million books, but also space for exhibition purposes and for a reading room.

All use of these valuable books will be under careful supervision because most of them are irreplaceable. Also, according to Metcalf, great care will be taken to maintain the right temperature, humidity, and light conditions in the new library. Ultra-violet rays and extremes in heat and moisture are particularly harmful to old books and manuscripts.

"Books need more care than people because they are not so adaptable to atmospheric conditions," said Metcalf.

The Widener Treasure Room, now vacant because of the transfer of most of its rare books to the new addition, has been occupied by the offices of the Catalogue Department. The Union Card Catalogue, listing all books in the University and in the Library of Congress, had become so large that more space was needed.