The governing body of any such city is hereby authorized to levy an annual tax on all taxable tangible property in such city to be used for the purpose of paying the cost and expenses of maintaining and operating such additional system of lights as hereinbefore provided and to pay a portion of the principal and interest on bonds issued by such city under the authority of Kan. Stat. Ann. § 12-1774, and amendments thereto. The revenue derived from such tax except for an amount to pay a portion of the principal and interest on bonds issued by such city under the authority of Kan. Stat. Ann. § 12-1774, and amendments thereto, shall be kept in a separate fund by the city treasurer, and shall be known as the “special lighting fund.”