Any portion of the principal proceeds derived from the sale of the bonds which the board of directors of the corporation may determine is not then needed for any of the purposes for which the bonds are authorized to be issued shall be invested in permitted investments. Any such securities, at any time and from time to time on order of the corporation, may be sold or otherwise converted into cash. The income derived from any investments shall be disbursed on order of the corporation for any purpose for which the corporation may lawfully expend funds.
Ala. Code § 2-6-115 (1975)