As a complete alternative to the authority now provided by Kan. Stat. Ann. § 2-129, the board of county commissioners of Montgomery county shall make an annual tax levy upon all of the assessed taxable tangible valuation of such county for fair purposes and to pay a portion of the principal and interest on bonds issued under the authority of Kan. Stat. Ann. § 12-1774, and amendments thereto, by cities located in the county but such tax shall not exceed a rate of 1/5 mill and is subject to the provisions of Kan. Stat. Ann. § 2-129h.