Coals may be considered both as a material of manufacture and as an instrument of trade. Heavy duties, accordingly, have been imposed upon their exportation, amounting at present (1783) to more than five shillings the ton, or to more than fifteen shillings the chaldron, Newcastle measure; which is in most cases more than the original value of the commodity at the coal pit, or even at the shipping port for exportation.
The exportation, however, of the instruments of trade, properly so called, is commonly restrained, not by high duties, but by absolute prohibitions. Thus by the 7th and 8th of William III chap. 20 sect. 8 the exportation of frames or engines for knitting gloves or stockings is prohibited under the penalty, not only of the forfeiture of such frames or engines, so exported, or attempted to be exported, but of forty pounds, one half to the king, the other to the person who shall inform or sue for the same. In the same manner by the 14th Geo. III chap. 71 the exportation to foreign parts, of any utensils made use of in the cotton, linen, woollen and silk manufactures, is prohibited under the penalty, not only of the forfeiture of such utensils, but of two hundred pounds, to be paid by the person who shall offend in this