In 1869 the output of pig iron made with raw bituminous coal and with coke exceeded for the first time the production of charcoal pig iron. In 1869 a Siemens regenerative fur nace was used by William F. Durfee for the puddling of iron at Bridgeport, Conn. Iron ore was imported from Canada in considerable quantity in 1873 and the following years. In 1879 importation started from Mediterranean countries, chiefly Spain, Algeria and Elba. Im portations from Cuba, so important at the present time, did not begin before 1884.
Natural gas was used for the first time for the manufacture of iron in 1874 at the Siberian Rolling Mill in Armstrong County, Pa.
In 1875 the output of pig iron made with bituminous coal exceeded for the first time that made with anthracite.
The Edgard Thomson Steel Company rolled in 1875 the first 60-foot rails made in the United States. The same year Whitwell fire-brick hot blast stoves were used at the Rising Fawn Furnace, Dade County, Ga.
The first steel wire nails were made in 1875 by Father Goebel at Covington, Ky.
Siemens-Cowper-Cochrane fire-brick hot blast stoves were erected in 1877 at the Crown Point Furnaces, Crown Point, N. Y.
The Brooklyn suspension bridge which was in process of construction between 1869 and 1883 was built entirely of American made steel wire cables, John A. Roebling being the engi neer.
Basic steel was first made in this country in 1884 at Steelton, Pa., by the Pennsylvania Steel Company in a Bessemer converter.
Armor plates to be made in America were first contracted for in 1887 by the Navy De partment with the Bethlehem Iron Company.
Basic open hearth steel was first manufac tured in the• States in 1888 at the Homestead Steel Works of Carnegie, Phipps Company, Ltd., at Homestead, Pa.
The progress made in the iron and steel in dustry during the 20th century to date consists in important manufacturing improvements that have resulted in economy and in increased pro duction. They include the mining, handling and treatment of ores, blast furnace construc tion and operation, coke making and steel manu facture. Improvements resulting in the produc tion of new steels or of steel of better quality have also been recorded. These were generally brought about through a more scientific treat ment of the metals made possible by remarkable progress in the science of metallography.
The advance in the handling and treatment of iron ore includes improvements in mining methods, in land and water transportation, in appliances for transferring the ore from rail way cars to vessels, to railway cars again and to furnace top and its introduction into the furnace. These operations are described by John Brikinbine as follows: °The bulk of the domestic iron ore used in the United States is not touched by the hand of man from the time it leaves the mine until it is converted into forms for sale, as rails, structural shapes, wire rods, sheets, merchant bars, etc., and in many of the operations the ore is dug by power shovels, or through chutes, so that even in mining but little hand labor is necessary. Lifted from its bed by dippers on power shovels, ore is loaded into railway cars or directed through into chutes, or mined by pick and shovels and shot into mine tram cars. The cars run to pockets feeding skips, which are raised by power and automatically dumped into waiting railway cars, except when climatic conditions, stagnant trade or the desirability of discontinuing operations, require that ore be stocked for future ship ment. Where necessary the ore passes through intermediate crushers to reduce the size of pieces; but in crushing, stocking or •reloading.
man directs the movement of machinery and touches but little of the ore.
aRailway cars, with their loads of iron ore, convey it to blast furnaces, or, as is the custom with most Lake Superior ores, to docks pro vided with pockets, into which the ore drops through the opened bottoms of the cars, while spouts connecting with the dock pockets de liver the ore by gravity into holds of ves sels specially constnicted for the iron ore trade. At the end of the vessel's trip, mechanical de vices remove the ore and deposit it in cars or on stock piles.
aAs lake navigation is suspended for five months in the year on account of ice, stock piles are accumulated at the mines, at receiving docks at lower lake ports, and at blast furnaces, where elaborate mechanical equipment facili tates the handling of this ore when used.