Iron for Wood.—The transition from sail to steam was accom panied by the transition from wood to iron. Iron canal barges had been in use since the first quarter of the 19th century, and in 1825 an iron steamer began running on the Shannon; but it was not until the year 1837 that the first iron vessel was actually classed by Lloyd's Register. The later tea clippers were mostly of composite construction, with iron frames and wooden planking; but during the '6os, iron gained ground both for steamers and sailing vessels. In 1870 over five-sixths of the tonnage under construction in British yards was iron; three-quarters of the tonnage consisted of steamships.
This double transition again placed Great Britain far ahead of all rivals. The clipper ship era in the United States had been succeeded, first by a great financial depression, and then by the Civil War, which led to the transfer of 715 American ships to British register. After the war, the energies of the American people were directed mainly to the development of their own great internal resources, and American ship-owners clung, with a strange conservatism, to wood and sail. British owners were greatly assisted by the fact that the coalfields, and the great centres of iron and steel production and engineering, were mostly within easy access to the ports, and they were quicker than any of their rivals to invest in iron and steam. In 187o there were already 1,202,134 tons of steam shipping on British register; the United States had only 192,544 tons registered for foreign trade; France had 154,415 tons. No other country had so much as io0,000 tons.
From this point the decline of the sailing vessel was rapid, and was accentuated by the further change over, in the '8os, from iron to steel as the material for shipbuilding. In 1870 about 16% of the world's tonnage consisted of steamers. By 1890 the pro portion had risen to 46%, and by 1900 to 62%, and it must be remembered that each ton of steam was equal in annual carrying capacity to three or four tons of sail. The iron wool clippers continued to struggle against the competition of steam in the Australian trade until the early '9os ; but by the beginning of the 20th century sailing tonnage counted for little on ocean routes.
only by the capacity of the ports. The 50,000-ton passenger liners of the north Atlantic trade are still exceptional ; but the true successors of the clipper ships, ranging from 800 to 2,400 tons, are liners and freighters ranging from 5,000 to 20,000 tons.
As regards speed, the record Atlantic passage by a sailing vessel was 12 days 6 hrs. in 1854, by the "James Baines," Boston to Liverpool. The steamer record is the "Mauretania's" 4 days io hrs. 41 min., Queenstown to New York ; but the supreme quality of the steamer is her certainty. The American clipper "Lightning" is said to have run 436 miles in 24 hours, an average of 18 knots; many cargo liners to-day are content with 12 knots. The sailing vessel, however, was at the mercy of the winds. To make her best speed she must sail at certain periods of the year, and even then her passage depended on her luck. In 1866 "Serica," a crack racing ship, was home from Foochow in 99 days ; in the following year she took 120. A whole fleet of homeward bound vessels might be detained for a fortnight or three weeks off the Scillies by contrary winds. The main advantage of the steamer is not a greater maximum speed, but the fact that, on the day she puts out from port, the date of her arrival can be fixed almost with the precision of a railway time-table. So great is the superiority of the steamer over a series of voyages that, while the tonnage on British register increased 150% in the half century between 1850 and 1900, its annual carrying-power was probably multiplied by seven.
This vast increase in carrying power, coupled with certainty as to the arrival of cargoes, has had momentous consequences. In the first place it has helped to build up the populations of the newer countries by permitting a huge expansion in emigration. In the ten years 1825-34 the average annual number of immi grants received by the United States was 32,00o. In the last decade before the World War it was 1,012,000. In the second place it has permitted the growth in the older industrial countries of massed populations dependent for their daily bread, and for the materials of the craft whereby they earn it, not merely on the arrival of millions of tons of imports in the course of a year, but on their arrival with absolute certainty in a steady daily stream. Finally it has raised the standard of living and broadened the outlook of people in all countries by permitting the exchange of goods on a vastly increased scale, and by facilitating travel and communication. For good or ill, our present civilization is the child of the steamship.