Now this is changed. The importers and merchants of London, Hamburg, and New York are not often those who own vessels and bring their own goods. Instead of this they have agents, who live permanently in each of the foreign ports, where they buy the merchandise they want and hire a vessel, or the needed space in a vessel, belonging to somebody else to bring them home. By the old way, the nation which had anything to sell carried it to the nation that would buy it, and brought back the best thing it could get in exchange; now the merchants go to various parts of the world, buy their cargoes, and order them sent home, in substantially the same way as you go a-shopping in town. This has brought out a new department of sea-labor, unknown, as a class, a century ago—the business of carrying goods which the owners of the vessels have no property in. In London, New York, Hamburg, and all other seaboard cities of this and other countries, the great majority of the shipping is owned, not by the merchants of the city, but by “transportation companies,” who agree to carry cargoes at a certain rate. [Illustration: THE SALOON OF A SAILING PACKET-SHIP, ABOUT 1840.] Merchant vessels may be divided into three classes, of which the first includes steamships and sailing-vessels planned primarily for freight transportation, which run back and forth between certain ports, and so constitute “lines” for freight. Such lines exist along even the remotest coasts, so that goods may be shipped directly, or by a single transfer, from any given seaport to almost any other in the world. Some of these lines, sailing between certain ports, are devoted to particular uses, such as those of oil-steamers and cattle-steamers. The oil-steamers run between America and Europe with American petroleum, and in the Black Sea and the Mediterranean with oil from Russia; the entire holds are divided into vast iron tanks for this liquid, which is poured into and pumped out of them as into and out of a great barrel. The cattle-steamers are specially arranged for the transportation of live stock, but one line, running between America and England, also carries passengers at a cheap rate. The second class of vessels consists of those which make the transportation of passengers their first object, loading their holds with first-class freight, for which high rates are paid in consideration of its swift delivery. The third class includes what are known as “tramp” steamers, which run irregularly, as the old sailing-vessels used to do, picking up cargoes wherever they find them and carrying them to any port. They are often of great size and power, but being under less close supervision are often less careful as to the safety of crews and cargoes, and are sometimes unseaworthy. They are always ready to answer any sudden demand for ships, their owners keeping watch of the chances and telegraphing to their captains where to go for their next cargoes.