SECTION 1. Section fourteen of the Philippine Tariff Act of nineteen hundred and nine, as amended by Acts Numbered Thirty-four hundred and twenty-nine and Thirty-eight hundred and eighteen, is hereby further amended to read as follows:
"SEC. 14. That there shall be levied and collected upon all articles, goods, wares, or merchandise, except coal, forest products, cement, guano, the minerals and ores of copper, lead, zinc, iron and steel metals, refractory gold ores, and sugar molasses, the products of the Philippine Islands, exported through ports of entry of the Philippine Islands, or shipped therefrom to the United States or any of its possessions, a duty of one dollar per gross ton of one thousand kilos, as a charge for wharfage, whatever be the port of destination or nationality of the exporting vessel: Provided, That articles, goods, wares, or merchandise imported, exported, or shipped in transit for the use of the Government of the United States, or of that of the Philippine Islands, shall be exempt from the charges prescribed in this section."