The exportation of the materials of manufacture, where it is not altogether prohibited, is in many cases subjected to considerable duties.
By the 8th George I chap. 15., the exportation of all goods, the produce or manufacture of Great Britain, upon which any duties had been imposed by former statutes, was rendered duty free. The following goods, however, were excepted: Allum, lead, lead ore, tin, tanned leather, copperas, coals, wool cards, white woollen cloths, lapis calaminaris, skins of all sorts, glue, coney hair or wool, hares wool, hair of all sorts, horses, and litharge of lead. If you except horses, all these are either materials of manufacture, or incomplete manufactures (which may be considered as materials for still further manufacture), or instruments of trade. This statute leaves them subject to all the old duties which had ever been imposed upon them, the old subsidy and one percent outwards.
By the same statute a great number of foreign drugs for dyers use, are exempted from all duties upon importation. Each of them, however, is afterwards subjected to a certain duty, not indeed a very heavy one, upon exportation. Our dyers, it seems, while they thought it for their interest to encourage the importation of those drugs, by an exemption from all duties, thought it likewise for their interest to throw some small discouragement upon their exportation. The avidity, however, which suggested this notable piece of mercantile ingenuity, most probably disappointed itself of its object. It necessarily taught the importers to be more careful than they might otherwise have been, that their importation should not exceed what was necessary for the supply of the home market. The home market was at all times likely to be more scantily supplied; the commodities were at all times likely to be somewhat dearer there than they would have been, had the exportation been rendered as free as the importation.