The principal amount of such gift or donation shall be set aside by the State Treasurer in a special fund designated: "Endowment Fund - Department of Archives and History," and moneys so deposited shall constitute an endowment fund for said department. In no event shall more than 10 percent of the amount remaining in said fund be expended in any one fiscal year. The Director of Finance shall invest or reinvest from time to time, at his discretion and with the approval of the Governor, all or any part or portion of said fund in such bonds as are authorized by the laws of Alabama governing investments in bonds by domestic life insurance companies, and the interest thereon shall be paid to said department by the State Treasurer upon a requisition signed by the director of said department and approved by the Governor.