Duval did not long honour his native country with his presence. On the restoration of Charles II he came to London as footman to a person of quality, but soon took to the road. Numerous stories are told of his boldness, his address, and fertility of resource. One of the most amusing is that in which he got an accomplice to dress up a mastiff in a cow's hide, put horns on his head, and let him down a chimney, into a room where a bridal merrymaking was in progress. Duval, who was one of the guests, dexterously profited by the general dismay to lighten the pockets of an old farmer whom he had seen secreting a hundred pounds. When the money was missed it was supposed that the devil had flown away with it. On another occasion, having revisited France, he ingratiated himself with a wealthy priest by pretending to possess the secret of the philosopher's stone. This he effected by stirring up a potful of molten inferior metal with a stick, within which were enclosed a number of sprigs of pure gold, as black lead is in a pencil. When the baser metals were consumed by the fire, the pure gold remained at the bottom of the pot. Overjoyed at Duval's skill as an alchemist, the priest made him his confidant and bosom friend, revealing to him his secret hoards, and where they were bestowed. One day, when the priest was asleep after dinner, Duval gagged and bound him, removed his keys, unlocked his strong boxes, and went off with all the valuables he could carry. Duval was also an adroit card-sharper, and won considerable sums at play by "slipping a card;" and he was most astute in laying and winning wagers on matters he had previously fully mastered. His career was abruptly terminated by his capture when drunk at a tavern in Chandos Street, and he was executed, after ten years of triumph, at the early age of twenty-seven.