=254. Specialties of different colonies.=—The island colonies (Jamaica, Barbadoes, etc.) sent plantation products. The sugar-cane supplied sugar and molasses and, by a simple process of manufacture, rum. American cotton until Whitney’s invention of the cotton-gin in 1793 came almost entirely from the islands, and indigo and various drugs were secured from the same source. The colonies on the mainland supplied a greater variety of products, by reason of their climatic differences. Nearly all of them contributed to the supply of skins and furs; and lumber and naval stores (pitch, tar, turpentine) were secured from the forests all the way from New England to Georgia. Different sections, however, had their specialties; the Carolinas sent rice, Virginia tobacco, New England codfish and whale-oil. =255. Commerce with Africa.=—There was a marked peculiarity in the commerce with Africa. The exports to this country always exceeded the direct imports by a considerable sum. An English writer of the eighteenth century tells about the manufactures which were sent out, and continues: “we have, in return, gold, teeth (_i.e._, ivory), wax, and negroes; the last whereof is a very beneficial traffic to the kingdom, as it occasionally gives so prodigious an employment to our people both by sea and land.” His meaning is this: the slave trade was so “beneficial” because the slaves which were purchased with beads and rum were not brought to England but shipped to the American colonies where they were put to work. The English figured, therefore, that they got not only the price of the slaves in American products, but also had the business of carrying them to America, and could hope for a future return from their labor in the field. It is estimated that 20,000 slaves a year were sent out during the eighteenth century, and the chief port of the trade, Liverpool, employed 190 ships as slavers in 1771.