SECTION 1. Section one hundred and forty-two of the National Internal Revenue Code, as amended, is further amended to read as follows:
"SEC. 142. Specific Tax on manufactured oils and other fuels.—On refined and manufactured mineral oils and motor fuels, there shall be collected the following taxes:
"(a) Kerosene or petroleum, per liter of volume capacity, two and one-half centavos;
"(b) Lubricating oils, per liter of volume capacity, seven centavos;
"(c) Naptha, gasoline, and all other similar products of distillation, per liter of volume capacity, eight centavos; and
"(d) On denatured alcohol to be used for motive power, per liter of volume capacity, one centavo: Provided, That if the denatured alcohol is mixed with gasoline, the specific tax on which has already been paid, only the alcohol content shall be subject to the tax herein prescribed. For the purpose of this subsection, the removal of denatured alcohol of not less than one hundred eighty degrees proof (ninety per centum absolute alcohol) shall be deemed to have been removed for motive power, unless shown to the contrary.
"Whenever any of the oils mentioned above are, during the five years from June eighteen, nineteen hundred and fifty two, used in agriculture and aviation, fifty per centum of the specific tax paid thereon shall be refunded by the Collector of Internal Revenue upon the submission of the following:
"(1) A sworn affidavit of the producer and two disinterested persons proving that the said oils were actually used in agriculture, or in lieu thereof.
"(2) Should the producer belong to any producers association or federation, duly registered with the Securities and Exchange Commission, the affidavit of the president of the association or federation, attesting to the fact that the oils were actually used in agriculture.
"(3) In the case of aviation oils, a sworn certificate satisfactory to the Collector proving that the said oils were actually used in aviation: Provided, That no such refunds shall be granted in respect to the oils used in aviation by citizens and corporations of foreign countries which do not grant equivalent refunds or exemptions in respect to similar oils used in aviation by citizens and corporations of the Philippines."