XXVIII.

THE EAST RIVER BRIDGE.

LAYING THE FOUNDATIONS UNDER WATER.—HOW THE WORK WAS PERFORMED.—THE CAISSON.—HOW IT IS MADE.—ITS MODE OF OPERATION.—WORKING UNDER WATER.—EXPLORING THE BED OF THE RIVER.—DESCENDING INTO THE BOX.—EFFECTS OF A GREAT PRESSURE OF AIR.—AN UNPLEASANT SENSATION.—A STRANGE SIGHT.—ACCIDENTS.—HOW A MAN’S ARM WAS CAUGHT. 426