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Every-day Science - Volume 6

Henry Smith Williams and Edward Huntington Williams

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Book Excerpt: 
. . .are combined, without the introduction of any new principle.

Derricks have been employed from a very early day. The battering-rams of the ancient Egyptians and Babylonians, for example, were virtually derricks; and no doubt the same people used the device in raising stones to build their temples and city walls, and in putting into position such massive sculptures as the obelisks of Egypt and the monster graven bulls and lions of Nineveh and Babylon.

CRANES AND DERRICKS.

The upper figure shows a floating derrick, the lower right-hand figure a combined derrick and weighing machine, and the lower left-hand figure a so-called sheerlegs, which is a simple derrick and windlass operated by hand or by steam power with the aid of compound pulleys.

The modern derrick, made of steel, and operated by steam or electricity, capable of lifting tons, yet absolutely obedient to the hand of the engineer, is a really wonderfu. . . Read More