open it; but not finding the bolt yield with gentle pressure, I added the other hand, and gradually increased the force until I exerted my whole strength, when suddenly something broke. I then tried to file the catch of the bolt, but that being cast iron, the file made no impression; we then endeavoured to cut away the stone in the wall which receives the bolt, but that was fortified with a bar of iron, so that that was impracticable; the picklocks were again applied, but with no better success; it now appeared complete check mate; and, as the last resource, it was proposed to return to the bridge, slip down the piles, and float along the canal on our backs, there being too little water to swim, and too much mud to ford it. Hunter then suggested the getting up the rope again, and attempting some other part of the fortress. In the midst of our consultation, it occurred to me, that it would be possible to undermine the gate: this plan was no sooner proposed than commenced, but having no other implements than our pocket knives, some time
