A fourth part of all the iron-works which have been constructed in this country have been abandoned by their projectors, in despair of competing with the cheap iron from abroad, which the low _ad-valorem_ tariffs have admitted to the American market. The story which these ruined works might tell, of hopes disappointed, capital sunk, and labor wasted, would be long and dreary. From an excellent diagram, appended to the "Guide," illustrating the duties on iron, the importations, and the price of the metal, for each year since 1840, we learn that the average annual importation of iron under the specific tariff of 1842 was 77,328 tons, while under the _ad-valorem_ tariff of 1846 it was 373,864 tons. The increase in the importation of foreign iron under the tariff of 1846 was more than ten times the increase of the population, and more than thirty-eight times the increase in the domestic production. The iron-masters of this country have been compelled to struggle against a host of formidable difficulties,--adverse legislation, the ruinous competition of English iron, the dearness of labor, and the high rates of interest on borrowed capital. These have all been met and, let us hope, in good part overcome. Slowly, and with many hindrances and disasters, the iron-business is gaining strength, and achieving independence of foreign competition and the tender mercies of legislators. Very conclusive evidence of this gradual growth is presented in the unusually accurate statistics of the "Iron-Manufacturer's Guide." Of the 1,209,913 tons of iron consumed in the United States in the year 1856, 856,235 tons, or seventy-one per cent, of the whole, was of domestic manufacture. The catalogue of iron-works shows that the country now possesses many extensive and well-constructed works, of which some are still owned by the men who built them, but the larger part have descended, at great sacrifices, to the hands of more fortunate proprietors. Beside the accumulated stock of machinery, knowledge of the ores and fuel has been gained, experience has refuted many errors and pointed out the dangers and difficulties to he overcome, the natural channels of communication throughout the country have been opened, and a large body of skilled workmen has been trained for the business and seeks steady employment. Whenever a rise in the price of iron stimulates the manufacture, the domestic production of iron suddenly expands, and increases with a rapidity which gives evidence of wonderful elasticity and latent strength. Twice within twenty years the production of American iron has nearly doubled in a period of three years. Twelve years ago no railroad-iron was made in the United States. In 1853 we imported 300,000 tons of rails, and in 1854 280,000 tons; but in 1855 only 130,000 tons were imported, while 135,000 tons were made at home, and in 1856, again, nearly one half of the 310,000 tons of rails consumed was of domestic production. The admitted superiority of the American rails has undoubtedly contributed to this result.