=374. The great wares of commerce. Coal.=—For the purpose of a summary survey the most important wares of commerce before 1800 can be designated as belonging to the two classes, colonial products and textiles. We shall have to note, in ensuing sections, striking changes affecting both of these classes, and the addition to the important wares of commerce of two new classes, mineral products and foodstuffs. Taking first the mineral products, and including coal with them, as common usage justifies us in doing, we find, at first sight, that this article takes a far lower rank among the modern wares than we should expect from its commanding importance in industrial life. There has been, it is true, a great growth in the coal trade, and considerable quantities are exported from England, Belgium, Germany, on occasion the United States, etc., for use in countries lacking coal mines, or at sea. There is an immense internal commerce in coal. In 1900 more than half of the tonnage carried on the railroads of the United States consisted of mining products; and of these coal certainly formed a very considerable, perhaps the major, part. Still coal does not rank among the chief wares of foreign trade. =375. Metals and Manufactures.=—An explanation of the comparative insignificance of coal in foreign trade is found in its bulk. An active industrial people can compress the value of coal, as it were, by using it near the mines for the production and transformation of other materials. Coal is transmuted into iron and manufactures, and so loses its identity, though it remains still the real power behind the exports of that character. Commerce in iron and steel, and the manufactures depending on them, has increased enormously in the course of the century, as the reader may readily suppose. Supplies of iron and machinery flow from the centers of production to the less advanced countries, and the simpler tools penetrate every nook and corner of the earth. Copper has grown greatly in importance, as its use for electrical appliances has extended, and now forms a considerable item in exchanges of countries like the United States and Germany.