Fig. 64.—Diagram for
Blue Room "When the two objects or sets of objects thus successively presented to the view are properly placed and sufficiently alike, the audience will be unaware that any change has been made. In some cases, in place of a single sheet of glass, two or more sheets may be employed.
"In the drawings, Fig. 63 represents a plan view, and Fig. 64 an elevation, of a portion of the mirror, designed to show its graduated opacity.
"a is a stage. It may be in a lecture-room or theater. b b are the seats for the audience in front of the stage. c c is a small room—eight or ten feet square and eight high will often be sufficiently large; but it may be of any size. It may advantageously be raised and approached by two or three steps from the stage a.
"d is a vertical mirror, passing diagonally across the chamber c and dividing it into two parts, which are exact counterparts the one of the other. The mirror d is so mounted that it can be rapidly and noiselessly moved diagonally across the chamber in the path represented by the dotted line d1, and be withdrawn whenever desired. This can conveniently be done by running it in guides and upon rollers to and from a position where it is hidden by a screen, e, which limits the view of the audience in this direction.
"In consequence of the exact correspondence of the two parts of the chamber c, that in front and that behind the mirror, the audience will observe no change in appearance when the mirror is passed across.
"The front of the chamber is partially closed at cx by a shield or short partition-wall, either permanently or whenever required. This is done in order to hide from direct view any object which may be at or about the position c1.
"The illusions may be performed in various ways—as, for example, an object may, in the sight of the audience, be passed from the stage to the position c2, near the rear short wall or counterpart shield f, diagonally opposite to and corresponding with the front corner shield cx, and there be changed for some other. This is done by providing beforehand a dummy at c´, closely resembling the object at c2. Then when the object is in its place, the mirror is passed across without causing any apparent change. The object, when hidden, is changed for another object externally resembling the first, the mirror is withdrawn, and the audience may then be shown in any convenient way that the object now before them differs from that which their eyesight would lead them to suppose it to be.
"We prefer, in many cases, not to use an ordinary mirror, d, but one of graduated opacity. This may be produced by removing the silvering from the glass in lines; or, if the glass be silvered by chemical deposition, causing the silver to be deposited upon it in lines, somewhat as represented by Fig. 63. Near one side of the glass the lines are made fine and open, and progressively in passing toward the other side they become bolder and closer until a completely-silvered surface is reached. Other means for obtaining a graduated opacity and reflecting power may be resorted to.
"By passing such a graduated mirror between the object at c2 and the audience, the object may be made to fade from the sight, or gradually to resolve itself into another form."
Hopkins in his fine work on "Magic, stage illusions, etc.," thus describes one of the many effects which can be produced by the Blue Room apparatus. The curtain rises, showing "the stage set as an artist's studio. Through the centre of the rear drop scene is seen a small chamber in which is a suit of armor standing upright. The floor of this apartment is raised above the level of the stage and is approached by a short flight of steps. When the curtain is raised a servant makes his appearance and begins to dust and clean the apartments. He finally comes to the suit of armor, taking it apart, cleans and dusts it, and finally reunites it. No sooner is the suit of armor perfectly articulated than the soulless mailed figure deals the servant a blow. The domestic, with a cry of fear, drops his duster, flies down the steps into the large room, the suit of armor pursuing him, wrestling with him, and kicking him all over the stage. When the suit of armor considers that it has punished the servant sufficiently, it returns to its original position in the small chamber, just as the master of the house enters, brought there by the noise and cries of the servant, from whom he demands an explanation of the commotion. Upon being told, he derides the servant's fear, and, to prove that he was mistaken, takes the suit of armor apart, throwing it piece by piece upon the floor."