Chap. XIV. ON PILES AND PILE-DRIVING. *07$

perronet’s pile-engine.

Fig. 1643.

once show how conveniently it may be moved to perform its operations. The platformlaid upon the deck of the boat being braced in all directions, the other timbers are fixe<J

Fig. 1644. pbrronet’s pile-driving engine.

upon it with facility, and may be taken down as readily when not required, and placedunder cover: by means of a ladder attached to the inclined braces at tbe back, theupper parts of the engine could be approached, and the tackle adjusted. To keepthe ram steady, it was made to slide within a frame, so that its motion could always bedepended upon, and there was no danger of its falling into the water.

Pile-driper by De Cessart, used at the bridge of Saumur . — The axis was 10 inchesdiameter, furnished witli a wheel, 12 feet in diameter, with trundles or round pinson the periphery for turning it. Eight men employed at this wheel raised at three turnsa ram of 1500 pounds 6 feet high ; a workman, by means of a cord, then unhooked the ram,which suddenly fell; but to regulate the height of the fall and the price for driving,it was determined that it should be limited to a stroke of 8 or 10 feet, giving the greatestfall at the time the greatest force was required to be applied to it. The price was deter-mined in this case at 20 shillings per pile, including the expenses of transport, and for thescaffold piles 10 shillings.

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