Ala. Code § 11-3-14
The county commission may deposit any funds arising from any special tax levied to pay bonds issued by said county which are in excess of amounts then payable on said bonds in some solvent savings bank in the State of Alabama in the name of the county or invest the same in interest-bearing securities issued by the United States government or by the State of Alabama. The interest accruing on such deposit or from such securities shall be a part of such special fund and shall be devoted to the same uses as the principal of said fund. The county commission shall require adequate bond of said bank to secure the safety of said deposit, which bond shall be in such sum as such county commission shall fix, having due regard to the safety of county funds.
Ala. Code § 11-3-14 (1975)