------+-------+--------------------- | United States. +-------+------------+-------- Years.|Number.| Tonnage. |Average | | |tonnage. ------+-------+------------+-------- | |Gross tons. | 1855 | 246 | 72,760 | 296 1860 | 275 | 69,370 | 259 1865 | 411 | 145,696 | 356 1870 | 290 | 70,621 | 244 1875 | 323 | 62,460 | 193 1880 | 348 | 78,853 | 229 1885 | 338 | 84,333 | 249 1890 | 410 | 159,045 | ------+-------+------------+-------- | United Kingdom. +-------+------------+-------- Years.|Number.| Tonnage. |Average | | |tonnage. ------+-------+------------+-------- | | Net tons. | 1855 | 278 | 106,872 | 385 1860 | 234 | 67,699 | 289 1865 | 453 | 211,665 | 467 1870 | 512 | 267,896 | 523 1875 | 428 | 226,701 | 530 1880 | 629 | 414,831 | 660 1885 | 487 | 221,918 | 456 | | | | | Gross tons.| 1890 | 632 |1,076,220[7]| 1,700 ------+-------+------------+-------- The startling steam tonnage of 1883 (nearly three-quarters of a million tons) built in Great Britain, of which 134,785 were built at Glasgow, 125,870 at the Tyne ports, and 117,776[8] at Sunderland, was followed by a great depression. In 1884 but a little over half that of the preceding year was built (415,095 tons); and in 1885 this was again almost halved, the output falling to only 221,918 tons, and the average size also falling off from 724 tons in 1883 to 456 in 1885. But in the last five years Great Britain has moved forward with a constantly accelerated pace, culminating in the vast figures of 1890, when she put afloat over 80 per cent. of the world’s production for the year. Nearly or, practically, quite all of the vast fleet represented by these figures are of iron or steel; the tonnage of the wooden steamers generally falling in later years in Great Britain to a total of 1,000 tons or less, and this made up of vessels averaging not more than 30 tons each. [Illustration: The City of Rome.] Steel may be said to have almost supplanted iron as a material; in 1880 but 10 per cent. of British steam vessels were built of this, as against 90 per cent. of iron; in 1890 but 4 per cent. were of the latter metal. There is, however, a tendency on the part of some owners to return to iron as less liable to the pitting caused by the galvanic action arising from want of homogeneity in the steel; a vessel’s bottom, unless well guarded by protective compositions, being frequently severely corroded, generally in small pits the size of a pea, but often extending to large patches.