And now for the explanation. Two small discs of glass which fitted over the ends of the tube were required. The ends of the tube were ground perfectly level and the glass discs were made with a "shoulder" (or sunk edge), so that when once they were placed on the ends of the tube they could not be moved laterally. The edges of these glass discs were also ground perfectly flat and were made to fit exactly on the ends of the tube.
One of the glass discs had a hole in the centre, and this hole was filled up, just before the commencement of the trick, with a little piece of moistened soap. If the soap were prepared too long beforehand it would become crumbly and dry; it has to be soft and damp.
The other glass disc was not prepared in any way. Before the commencement of the trick the disc with the hole in it was placed on the top of the fourth tumbler--and therefore to the performer's right. The other disc was laid on the top of the second tumbler in the row of four.
The piece of paper tucked into the glass chimney was half of a double sheet of note-paper. (Tear a double sheet from side to side.)
Begin by taking up the glass chimney, removing the paper, picking up the hat pin and rattling it inside the chimney--thus showing that it is not prepared in any way for the trick.
Put the chimney down, pick up the paper and tear it in halves. (The object of having half a double sheet is to enable the conjurer to tear it easily; the crease is ready for him.) The action of tearing the paper is proof that there is no trickery in the paper.
Place one piece of paper on the top of the fourth tumbler (and therefore over the disc with the hole in it). Dip the other piece of paper into the glass bowl, shake it a little, and lay it on the top of the second tumbler. Take the piece from the fourth tumbler, wet it in the same way, and replace it on the top of the fourth tumbler.
Thus both pieces of paper are now wet and are over the two glass discs. Pick up the piece of paper on the second tumbler, secretly taking with it the glass disc (which, of course, is under the paper) and place it on the top of the tube, taking great care not to let the glass disc "talk" against the top of the chimney; the audience must not hear the slightest "chink" of glass knocking against glass.