The registered American tonnage in the foreign trade grew from 123,893 tons in 1789 to 667,107 tons in 1800; for during the wars growing out of the French Revolution the American Mercantile Marine actually became the principal carriers of Europe, as at one time the Dutch and the English had been. Thus for a second time the marine showed how sensitive it was to the effect of war. But the war of 1812 caused severe losses to American merchant ships, yet, on the other hand, American privateers played havoc with English shipping. The effect, even in those days of comparatively few ships, is at once seen by looking at the port of Liverpool, the natural haven for American ships arriving in Europe; for whereas in 1810, 6729 ships entered that port, only 4599 came in during the year 1812. On the other hand, as soon as peace returned these figures jumped up, and from 1815 to 1860 shipping went ahead quickly. For the United States were fast developing their industries, opening up trade, and therefore had every need of a Mercantile Marine. The legislation of Congress in 1828 opened up American ports to cargo-carrying British ships from any country where American vessels were on a similar footing to British ships, and two years later the West Indies were opened to American shipping. In 1849 Great Britain adopted the Free Trade policy, and full reciprocity was established between British and American merchant vessels. The history of the clipper ships and the competition between Great Britain and the United States for the ocean-carrying trade has already been related in this volume. It is only necessary once more to emphasise that war had yet again a good deal to do with the future of the American Mercantile Marine, for the Civil War of 1861 took away any chance which remained to American ships of continuing as the great sea-carriers. The American mind had to concentrate on fighting. Meanwhile, much of the tonnage had passed under other flags, while in Great Britain the accessibility of coal deposits, the cheapness of labour, the successful introduction of iron for shipbuilding, the great advances in ship construction, and especially the wonderful progress of the steamship, had been able to give back to Great Britain her supremacy as a Mercantile Marine. And when the Civil War was over, America was too interested internally to pay a maximum amount of attention to ocean trading.