Page:Popular Science Monthly Volume 38.djvu/343

Rh a silvery luster, and oftentimes more or less porous or "honey-combed" near the upper surface, The purpose of this "refining" was, as the name suggests, the purification of the metal previous to its being treated in a puddling-furnace for final conversion into wrought iron. At the present day the "refinery" is rarely employed, improved methods having rendered it unnecessary.

The invention of the "puddling process" is usually ascribed to Henry Cort, of Gosport, England, who patented it in 1784. This process was a great improvement over that of the "blomary fire," inasmuch as the labor was diminished, and, as the metal was not in contact with the fuel, therefore raw mineral coal, which was much cheaper than charcoal, could be used with natural draught, thus dispensing with all blowing machinery. The process, as practiced on its introduction into America, consisted substantially of melting refined pig iron on the sand bottom of a reverberatory furnace, and stirring the pool (or "puddle," whence the name of the process) of molten metal until it became converted into a granular, pasty mass of wrought or forgeable iron, as the result of the decarbonizing action of the heated air passing through the furnace and over the metal. This granular mass of metal was divided by the "puddler" (as the workman was called) into several separate "balls," or "loups," which were taken in turn to a "shingling hammer," and "shingled" into "blooms"; this last operation being precisely similar to the shingling of the "ball" from a blomary fire, already described. Figs. 22 and 23 are respectively vertical and horizontal longitudinal sections of one of the earlier forms of "puddling-furnace," in which e is the sand bed of the puddling-chamber, d the "bridge-wall" which separated the fuel on the grates b of the "fire-box" from the iron in the puddling-chamber e, i is the chimney-flue, and k a lever for raising the door j. In some of the early puddling-furnaces in New England and eastern Pennsylvania the fuel used was dry split wood; and as late as 1858 dry pine wood was used for puddling and heating at the Hurricane Rolling-Mill and Nail-Works in South Carolina. This was probably the last instance of the use of wood as a fuel for such purposes in the United States.

Soon after the introduction of the puddling process into this country, Mr. Samuel Baldwyn Rogers, of Nant-y-glo,