It was the same with Cort's second patent, in which he described his method of manufacturing bar-iron from the ore or from cast-iron. All the several processes therein described had been practised before his time; his merit chiefly consisting in the skilful manner in which he combined and applied them. Thus, like the Craneges, he employed the reverberatory or air furnace, without blast, and, like Onions, he worked the fused metal with iron bars until it was brought into lumps, when it was removed and forged into malleable iron. Cort, however, carried the process further, and made it more effectual in all respects. His method may be thus briefly described: the bottom of the reverberatory furnace was hollow, so as to contain the fluid metal, introduced into it by ladles; the heat being kept up by pit-coal or other fuel. When the furnace was charged, the doors were closed until the metal was sufficiently fused, when the workman opened an aperture and worked or stirred about the metal with iron bars, when an ebullition took place, during the continuance of which a bluish flame was emitted, the carbon of the cast-iron was burned off, the metal separated from the slag, and the iron, becoming reduced to nature, was then collected into lumps or loops of sizes suited to their intended uses, when they were drawn out of the doors of the furnace. They were then stamped into plates, and piled or worked in an air furnace, heated to a white or welding heat, shingled under a forge hammer, and passed through the grooved rollers after the method described in the first patent.