Читать книгу Water Wizardry - Arthur Wellesley Pain - Страница 8

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A soda-water tumbler, a jug containing from a quarter to half a pint of water, and a cup of coffee with a little milk in it are needed for this experiment.

The trick is to pour both the coffee and the water into the big tumbler and then separate them again. Possibly somebody will attempt this feat by first placing a small tumbler in the large one, pouring the coffee into the small tumbler and the water around it. But can it be said that you pour both the coffee and the water into the tumbler when you really pour the coffee into another glass placed inside the tumbler? No, that solution does not work.

Here is the way in which you carry out your intentions.

Pour the coffee into the big tumbler and place on it a disc of thin cardboard; the disc should reach nearly to the edge of the tumbler. Then pour the water very slowly, a few drops at a time, on to the top of the cardboard, which breaks the fall of the water. The water runs off to the edge, and as the coffee is heavier than the water the latter remains on the top. The cardboard disc floats upwards with the water, and so the first half of the trick is accomplished.

The separation of the liquids can be brought about in two or three ways. For example, you can offer to drink the coffee without drinking the water, and you achieve this apparent miracle by merely putting in a straw and sucking up the coffee; in that way you have separated the two liquids.

With the help of a scent spray you can pump the water into the jug again, taking great care, of course, not to disturb the surface of the coffee. You can also take out nearly all the water with a small sponge and the remainder with a piece of blotting paper.