The moneys or securities composing the trust funds given or bequeathed to the board shall be receipted for by the Secretary of the Treasury, who shall invest, reinvest, or retain investments as the board may from time to time determine. The income as and when collected shall be deposited with the Treasurer of the United States, who shall enter it in a special account to the credit of the Library of Congress and subject to disbursement by the librarian for the purposes in each case specified; and the Treasurer of the United States is authorized to honor the requisitions of the librarian made in such manner and in accordance with such regulations as the Treasurer may from time to time prescribe: Provided, however, That the board is not authorized to engage in any business nor to exercise any voting privilege which may be incidental to securities in its hands, nor shall the board make any investments that could not lawfully be made by a trust company in the District of Columbia, except that it may make any investments directly authorized by the instrument of gift, and may retain any investments accepted by it.