OPEN-HEARTH FURNACES

Iron is converted into steel by the basic or open-hearth method in the

furnaces shown here. The 100-ton ladles are in position at the tapping

side of the furnaces to receive the molten steel.]

[Illustration: _Reproduced by permission of the Philadelphia Museums._

The Wonder Book of Knowledge The Marvels of Modern Industry and Invention, the Interesting Stories of Common Things, the Mysterious Processes of Nature Simply Explained · 第 111 / 162 题