?

V

in its power to blow up the other," he assured Charles II.

In 1655 the Marquis of Worcester invented a "ship-destroying engine" which, like the Dutch device, was actuated by clockwork, but it required a diver to attach it to the ship which was to be attacked, and does not appear to have been used. Indeed, the problem which the early inventor failed to overcome was the elimination of the human agency necessary to operate the mine.

It was left to David Bushnell, the American, who has been called the " Father of the Submarine," to evolve the idea of detonating mines by contact. Even Bushnell's early attempts at mining were on the lines of his predecessors,   and   the   object  of his   sub-

marine, the Turtle, was to approach an enemy vessel under water so that the single operator, while submerged, could drive into the ship's side a wooden screw to which was attached a mine containing 150 lbs. of explosive with a time-controlled mechanism. The Turtle was sunk after an abortive attempt to destroy the British 64-gun ship Eagle in the Hudson River during the American War of Independence, and Bushnell then invented what appears to have been the first contact mine : a keg with conical ends, filled with gunpowder, supported in the water by buoys, and fired by an ordinary gunlock and hammer. His first attempt with one of these "trigger-mines" was in 1777 against the British frigate Cerberus while she lay at anchor in the Con-