This is not a new trick, but an improvement has been added to it which makes it more effective.
A small pill-box is opened and is shown to contain three corks. The cover is put on and the box is shaken. When it is reopened, it is found to contain six corks. These are poured out on the table.
Use a large pill-box, which has a cover identical with the bottom. The “collar” of the box being removable, the top and bottom are reversible.
By the old method, three corks were glued to the inside of the cover; but in the improved version, they are simply stuck there by dabs of beeswax or diachylon (lead plaster).
The box is shown to contain three corks. The cover is put on without showing the interior. The fact that the lid may be lifted thus indirectly proves that it is empty.
Then the box is shaken, and is turned up side down in the action. This loosens the corks from the erstwhile lid; and when the new lid (formerly the bottom) is lifted, there are six corks which can be poured out on the table. If the corks are very lightly attached, the reversal of the box will be unnecessary.