This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
By George W. Catlin
The performer presents to his audience two pasteboard covers, one bottle and one glass. Saying that he wishes to secure the safety of the bottle and glass, he places covers over them, cautioning the audience to note carefully which cover incloses the glass and which the bottle. Then he says that, to prevent any misunderstanding as to their positions, it is desired the audience designate which cover holds the glass. The response will be unanimous, "the left" or "the right" as the case may be, but on raising that cover the bottle is exposed. Covering the bottle again, and asking the audience if they were quite sure that their eyes did not deceive them, he states that the glass is really under the cover just lifted and returned to its place. To prove it, the cover is lifted again, to show the glass this time. The changing can be done as often as desired, or will amuse the crowd.
Ill: Under Each Cover Used Is a Bottle and Glass, and by Pinching the Cover the Bottle is Made to Rise with It, Thus Leaving the Glass in View
The secret of the trick consists in the use of two covers, two bottles and two glasses, and the manner of performing it is as follows: The bottles are bottomless and of such size as to admit the glass without sticking. A round hole is cut in one side of each bottle, about 2 1/2 in. above the bottom. This can be accomplished in a drill press by using a round copper tube, with fine emery applied to its end, as a drill. The hole should be so placed that a finger will strike the top of the glass when both bottle and glass are set on the same surface. If dark-colored bottles are used, a false bottom can be made and fitted in each bottle above the upper edge of the glass. This bottom can be cemented in place and made liquid-tight, so that some wine may be placed in the bottle and poured into the opposite glass to show that it holds liquid. In doing this part of the trick, make no more changes with the wine in one glass.
Under each cover is a bottle and tumbler, and by pinching the cover, the bottle is made to rise with it, thus leaving the tumbler in view. When it is necessary to show the bottle, just raise the cover, and the bottle covers the glass. When the bottle is lifted from the table, the thumb is inserted in the hole to press the tumbler against the opposite side, where it is held and raised with the bottle. Be sure to keep the side of the bottles with the hole back and away from the audience.
It will be seen that it matters not which cover is mentioned ; the performer can show just the article he desires.