“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 in Fig. 1. 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 _c_^2 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._, to which I contributed the Introduction and other chapters, 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 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 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.”