“For soft steel we use the open-hearth, but for stuff like yours the Bessemer process has advantages,” said Jasper, turning to the pear-shaped vessels. “By comparison with a steelworks plant, our converters are small. Well, we start with the melted pig-iron, a special hæmatite mixture, and we burn up the sulphur, silicon, and so forth——”
He signalled, and a man across the pit replied: “Mr. Marsden’s at the cupolas. All’s ready, sir.”
A bell rang, and a converter tilted until the party looked into its luminous red throat. Then the roof and floor and columns shone, and a ladle swung across the pit. One did not see the stuff it carried, but trembling illumination marked its track. The ladle turned up, and a cascade of liquid iron poured into the converter’s mouth. Then it vanished and, but for the ghostly, phosphorescent glow about the converter, all was dark. The converter swung up, until its muzzle was under the pierced roof, and the gloom was banished by a flood of intense, overwhelming light.
A splendid pillar of flame leaped through the gap. One saw the flakes of scale on the iron floor and the scratches in the plates. Ledward noted the lines in Jasper’s face and thought him preoccupied. Carson studied the tossing fire, and then touched Ledward.
“I don’t know who is blowing, but the fellow seems clumsy. Go for Marsden; he’s at the cupolas.”
Ledward nodded and went down the steps. His shortest line was along the platform, but by the converters the rail was cut and the smooth plates were touched by puzzling light and shadow. Harry did not want to risk a plunge to the pit. Crossing the floor, he found the manager by the upright furnaces where the pig-iron was melted.
“Mr. Carson wants you. I think he’s not satisfied about the converter man.”
“Black’s a first-class blower,” Marsden replied. “I’ll come along.”
When Ledward went off Carson resumed:
“The air blown into the vessel is burning up the impurities. As the temperature rises they leave the iron and combine with the oxygen. Each gives the flame its characteristic tint, and the blower goes by time and color. If he did not stop at the proper moment, the iron would burn——”