The most direct information regarding Opre comes through that eminent family of conjurers known as the Bambergs of Holland. At this writing, "Papa" (David) Bamberg, of the fourth generation, is prominent on the Dutch stage, and his son Tobias David, known as Okito, of the fifth generation, is a cosmopolitan magician, presenting a Chinese act. According to the family history, traceable by means of handbills, programmes, and personal correspondence, the original Bamberg (Eliazar) had a vaulting figure in his collection of automata in 1790, fifty years before Robert-Houdin became a professional entertainer. This figure was made by Opre, to whom all conjurers of that time looked for automata and apparatus. David Leendert Bamberg, of the second generation, who also had the vaulting figure, was the intimate friend and confidant of Opre and was authority for the statement that Opre's son sold in Paris the various automata made by his father, which later Robert-Houdin claimed as his own invention. It may be noted that Robert-Houdin never invented a single automaton after he went on the stage in 1845, and as Opre died in 1846, the coincidence is nothing if not significant. CHAPTER V THE OBEDIENT CARDS--THE CABALISTIC CLOCK--THE TRAPEZE AUTOMATON _The Obedient Cards._ To trace here the history of three very common tricks claimed by Robert-Houdin as his own inventions would be sheer waste of time, if the exposure did not prove beyond doubt that in announcing the various tricks of his répertoire as the output of his own brain he was not only flagrant and unscrupulous, but he did not even give his readers credit for enough intelligence to recognize tricks performed repeatedly by his predecessors whom they had seen. Not satisfied with purloining tricks so important that one or two would have been sufficient to establish the reputation of any conjurer or inventor, he must needs lay claim to having invented tricks long the property of mountebanks as well as reputable magicians. The tricks referred to are the obedient card, the cabalistic clock, and the automaton known as Diavolo Antonio or Le Voltigeur au Trapèze. [Illustration: Card trick as featured by Anderson in 1836-37. From a poster in the Harry Houdini Collection.] The obedient-card trick, mentioned on page 245 of the American edition of his "Memoirs," as "a novel experiment invented by M. Robert-Houdin," can be found on the programme of every magician who ever laid claim to dexterity of hand. Whether they accomplished the effect by clock-work or with a black silk thread or a human hair, the result was one and the same. It has also been worked by using a fine thread with a piece of wax at the end. The wax is fastened to the card, and the thread draws it up. The simplest method of all is to place the thread over and under the cards, weaving it in and out as it were, and then, by pulling the thread, to bring the different cards selected into view.