Modern Magic: A Practical Treatise on the Art of Conjuring

When the performer desires to perform the trick, he places the empty glass upon b, and conceals it with a cover of any kind. Standing carelessly behind the table, and keeping the attention of the audience occupied by any observations he may deem most appropriate for that purpose, he takes hold with his right hand of the handle h, and turns it outward, thereby lowering the empty glass into d. As soon as he feels that it will sink no further, he shifts his hand to the handle a, and therewith draws the cylinders back so as to bring c under b, and then, by turning g, gently raises the full glass of water up through b to the surface of the table. The reader will now perceive the reason why, as already mentioned, the piston in d is made a little tight, so as to require the assistance of the handle to raise it into its position. It is necessary that this piston, when once depressed with the object to be changed, shall remain down while the hand is shifted from handle h to handle g. If it were not made to work somewhat stiffly, the moment the handle h was released the piston would instantly fly up again with the object upon it, thus neutralizing what had been already done. The cylinder c, which is to produce the substitute object, is not brought under b until the hand of the performer is already on the handle belonging to it, and can thereby check its upward ascent as may be necessary.