Du Vall, growing bolder, said: "Sir, I have spent most of my time in the study of alchemy, or the transmutation of base metals into gold, and have profited so greatly at Rome and Venice, from association with men learned in that science, that I can change several metals into gold by the help of a philosophical powder, which I can prepare very speedily."
The prospect of immense riches that might be his, if only he cultivated the acquaintance of this man of science, dazzled the confessor. "Friend," he said, "such a thing as this will indeed be a service to the State, and particularly grateful to His Majesty the King, who, as his affairs stand at present, is in great need of such a curious invention. But," he added, with some remains of cunning criticism, "before I credit what you say, so far as to communicate it to His Majesty, I must see some proof of your skill."
Du Vall agreed; but said, as only a poor student of these things, he had not the appliances necessary. These the confessor agreed to provide, and fitted up a laboratory for him in his own house. Everything being complete, Du Vall gave a demonstration of his alchemic science. He took several metals of the baser sort, and put them into a crucible, the confessor watching him the while. Du Vall had prepared a hollow stick, into which he had introduced several inlays of real gold; and with this stick he stirred the white-hot crucible, until the base metals were in a flux, and the stick itself was almost entirely consumed. On the crucible being cooled, and its contents examined, it was duly found that a considerable amount of gold was mixed with what had been base metals.
The Jesuit was delighted with the success of the experiment, and a series of equally satisfactory tests was entered upon. Du Vall at last fully acquired his confidence, and a complete knowledge of where his treasure was deposited, and, finding him one evening in a heavy sleep (to which he had perhaps contributed by drugging his wine), gently stole his reverence's keys, earned off as much of his hoarded wealth as he conveniently could, and hastened to England.
It was, for several reasons, high time he returned to our shores. There was, his biographer tells us, no room in France for a highwayman. "In truth, the air of France is not good for persons of his constitution, it being the custom there to travel in great companies, well armed, and with little money. The danger of being resisted, and the danger of being taken, are much greater there; and the quarry much lesser than in England. And if, by chance, a dapper fellow, with fine black eyes, and a white peruke be taken there, and found guilty of robbing, all the women in the town don't presently take the alarm, and run to the King to beg his life."
So we see that the narrator of Du Vall's life, certainly did not approve of the hero-worship accorded him.
But Du Vall's career was now fast drawing to a close. His exploits as a highway chevalier had grown too notorious for him to be allowed to range any longer at will on the roads around London. At times, perhaps fully informed of his exceeding danger, he would employ himself in another art, in which he was an expert—the art of cheating at cards, in which an exceptional sleight-of-hand served him in good stead. Apart from these qualities, a handsome personal appearance, and a skill in dancing and playing the flageolet, he seems to have been as ignorant as any other ex-stable-boy, or page-boy of his era; for in a curious notice of him in the London Gazette of January 1670, he is described as a man "of singular parts and learning, though he could neither read nor write." The different clauses of this eulogy seem at first sight quite irreconcileable; but the "learning," no doubt, refers rather to social graces, than to ordinary education.
He was captured when the worse for drink, at a tavern called the "Hole in the Wall," in Chandos Street, Covent Garden. He had three pistols in his pocket at the time, one of them "which would shoot twice," and had a sword at his side. "If he'd been sober, it was impossible he could have killed less than ten," says the author of the Memoires; adding, "He would have been cut as small as herbs for the pot, before he would have yielded to the bailey of Westminster," only the drink he had taken did not permit him the use of his legs.
He was executed at Tyburn, on January 21st, 1670, in spite of the many efforts made to secure a reprieve. After the hanging, he was given a lying-in-state at the "Tangier" tavern, St. Giles's, the room being draped in black, relieved with escutcheons. Eight candles burnt around him, and eight tall gentlemen in long cloaks kept watch. Many ladies of fashion and beauty went, masked, with tear-stained faces, to see him; a thing which seems incredible to ourselves, and was in fact considered extraordinary at the time. The author of the Memoires himself realised this, for we find him declaring the truth of it; although he says he expected to be accounted by his readers "A Notorious Lyer."