It is the intention of the Legislature of Alabama that the tax herein levied shall apply to all utilities, as defined herein, in the State of Alabama. With respect to every tax exemption which may be enacted into law subsequent to the enactment of this article, there shall be a presumption that such exemption does not apply to the tax herein levied unless the statute containing such exemption shall make a specific reference to this article and shall clearly show a legislative intention to make such exemption applicable to the tax herein levied.