National Geographic : 1917 Aug
SCAFFOLDING AROUND A SHIP UNDER CONSTRUCTION AT NEWPORT NEWS ROLLING STRUCTURAL STEEL AT BETHLEHEM, PENNSYLVANIA There are two cross-roads in the steel industry. All roads lead from the raw materials to pig iron. Thefrce they branch out again to the puddling furnace, the open-hearth furnace, the crucible furnace, etc. Then they converge again to the ingot, only to branch out once more into the infinite variety of products of the roller mill. Pig iron has often been called the common denominator of the iron industry, and the ingot the parent of all wrought steel. Out of such mills as this will come the structural beams for the shipping that may decide the issues of the world war.