The Librarian of Congress may from time to time transfer to other governmental libraries within the District of Columbia, including the Public Library, books and material in the possession of the Library of Congress in his judgment no longer necessary to its uses, but in the judgment of the custodians of such other collections likely to be useful to them, and may dispose of or destroy such material as has become useless: Provided, That no records of the Federal Government shall be transferred, disposed of, or destroyed under the authority granted in this section.