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216 shawl should be about six feet square. It should rest about nine inches from the stage when hung up. Practice to let as few seconds as possible elapse between the moment of suspending the shawl and dropping it. The reappearance of the performer is easily accounted for.

.—One of the cleverest illusions performed with the aid of mirrors is that known as the "Blue Room," which has been exhibited in this country by Kellar. It is the joint invention of Prof. John Henry Pepper, of Ghost illusion fame, and James J. Walker, both of England. It was patented in the United States by the inventors. The object of the apparatus is to render an actor, or some inanimate thing, such as a chair, table, suit of armor, etc., visible or invisible at will. "It is also designed," says the specification in the patent office, "to substitute for an object in sight of the audience the image of another similar object hidden from direct vision without the audience being aware that any such substitution has been made. For this purpose employ a large mirror—either an ordinary mirror or for some purposes, by preference, a large plate of plate-glass—which is transparent at one end, and more and more densely silvered in passing from this