Just then a warning cry sounded as the dolly broke through the clay dam that holds the metal in the furnace. Fire, scorching, burning fire leaped from the opening made with the dolly. The air was filled with brilliant, hissing stars as large as the palm of a man's hand. Some whirled like pin-wheels; others, holding their perfect shape, described graceful curves in the air, or exploded. Men shaded their eyes, drew themselves together, and tried to shrink away from the terrific heat. But there was no avoiding it. The monkey-man who had broken through the clay dam staggered away from the opening thus made, shouting hoarsely for water. Following the explosive stars, a river, almost blood-red, burst from the furnace with a roar, quickly changing into a river of saffron. Hissing and snapping the molten metal burned its way along through the sand-packed gutters, and shot from the ends of the gutters and into the waiting ladles on the flat cars at the foot of the platform. Everywhere the air seemed filled with fiery shapes reaching for human prey. Under foot there was danger on every hand, for a single misstep would plunge one into this all-consuming flood. The slag, or as much of it as possible, ground its way much more slowly, along another channel, to be gathered up and used over for other purposes at some later day. As one ladle was filled the waiting train would move up, bringing a new set of cars under the ends of the gutters, and when at last all the cars had been loaded the train moved off, the ladles glowing in the darkness of the night, until in the distance they became mere eyes of fire. The Iron Boys drew a deep sigh as the operation was concluded. Four hours would elapse before another cast would be made from number four furnace, but here and there along the row of huge cones stars were bursting, streams of hot, yellow lava flowing and men shouting, snarling or begging for water. "It is terrible, yet grand!" exclaimed Steve Rush, wiping the perspiration from his brow. Even where they stood, at one side of the furnace, the heat was well-nigh unbearable. "It strikes me as being grandly hot," answered Jarvis. "Whew, a fellow doesn't need his winter underclothing on in this job, does he?" "The furnace men don't seem to wear any at all," laughed Rush. "I should think they would burn their skin off. I don't know whether I can stand this game or not, but I'll try it. I wonder what we are going to do?" "I will find out from the foreman." The foreman was not on hand at the moment, but the head melter, known under the name of Pig-Iron Peel, had received orders regarding the Iron Boys. He motioned them to approach, when a furnace hand told him who they were. He asked the name of each boy in a hoarse, gruff voice. "Who are you?" demanded Jarvis. "I'm the Pig," answered the melter, his red face wrinkling into a grin, which was quickly smoothed out as if the effort hurt him. "Pig-Iron Peel," he added. "Ho, ho!" roared Bob immoderately.