Modern Magic: A Practical Treatise on the Art of Conjuring

Occasionally a refractory spectator may insist upon the wrong orange (i.e., that containing the genuine coin) being cut open first. As you have offered the audience the choice, you cannot well resist this; but it makes very little difference. In accordance with the general desire, you cut open the orange, and show the coin (No. 3), drawing particular attention to the mark. Its identity being fully established, you offer, for the general satisfaction, to pass the same coin into the second orange. Being satisfied that it was the genuine coin in the first case, the audience will the more readily believe that it is so in the second; but in this case you should cut open the second orange yourself, as it will be necessary to again substitute the genuine florin before you hand the coin to be examined.