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

by Unknown

[27] Illustrations by courtesy of The Brunswick-Balke-Collender Co.

[28] Illustrations by courtesy of the Addressograph Co.

[29] Illustrations by courtesy of the Pyrene Manufacturing Co.

[30] Illustrations by courtesy of Gatchel & Manning.

[31] Courtesy of Mr. Charles L. Trout.

[32] Illustrations by courtesy of the Bethlehem Steel Co.

[33] Illustrations by courtesy of the Bethlehem Steel Co.

[34] Illustrations by courtesy of the Bethlehem Steel Co.

[35] Illustrations by courtesy of the Bethlehem Steel Co.

[36] Illustrations by courtesy of the Bethlehem Steel Co.