“Now,” said Mr. Prescott, “we’ll start for some more giants. Coming, Farnsworth?”
“Sorry, not to-day. Call again!”
“The steel mill comes next on my program,” said Mr. Prescott, when they went out. “I want you to see a Bessemer converter, an open hearth, and some crucibles, because that practically covers the different methods of making iron and steel.
“Here is the Bessemer converter. You see it is an iron cylinder made of wrought iron plates, and it tapers off at the top in a conical end. See. It is swinging down to be filled almost as easily as you can turn your hand over. In a moment it will stand up again, twenty-five feet tall.
“Bessemer got hold of the idea that air could be used instead of fuel. They say he risked his life in his experiments. He worked a long time, but he won, and the Bessemer converters started the boom in steel.
“See it come up again, with fifteen tons of hot pig iron in it. Down in the bottom of the converter is a blast chest where the air is forced in under pressure, after it has been blown into a tank by blowing engines.”
“O-o-oh!” exclaimed Billy, as the top of the converter seemed to burst into flame, and a shower of sparks came down.
“That,” said Dr. Crandon, “is surely a fearful sort of thing!”
Then the flame began to drop slowly, and they saw that the converter itself was safe.
“This process burns out all the carbon. Bessemer was trying to make wrought iron when he started out. Now they put back the right amount of carbon, and make the iron into steel.