I define magic thus: Magic is the illusion that is created when a series of natural movements apparently causes an unnatural, or magical, result. For example if I show a coin in my right hand and apparently place it in my left hand in so natural a way that the onlookers are convinced it is really there, then when I pretend to make the coin vanish and show the left hand empty, for them the illusion of magic has been created. But if, on the other hand, I have first played pitch and toss with the coin, flinging it from hand to hand, or have made the action of placing the coin in the left hand with unnatural swiftness, suspicion will at once arise in the minds of the onlookers. When the left hand is shown empty they arrive at once at the right conclusion, namely, that the coin was never placed there. There is no illusion therefore no magic.
Jean Hugard – Hugards Magic Monthly