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THE IMMOVABLE CARD.
If a card, such as an ordinary visiting card, is turned down about a quarter of an inch at each end, at right angles to the rest of the card, and then placed on a table so as to rest on the turned edges, you may safely challenge most persons to blow it so as to make it turn over on the other side. It would naturally seem easier to overturn a card so prepared, than one whose shape remained unchanged; but whoever tries it will find that the facts are otherwise.
The card can be overthrown, however, by blowing on the table, toward the card, as the stream of air is then reflected against its under side.
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A TRIPLE BRIDGE.
This may be constructed by means of three table-knives, in the manner illustrated in the figure. Three goblets or tumblers will serve as the piers; these are to be arranged in a triangle, a little farther from each other than the length of the knives. Lay two of the knives on the table, with the blades crossing each other. Then pass the blade of the third knife over the uppermost blade of the other two, and under the undermost; then take them up and place them with the ends of the handles on the rims of the glasses. The bridge now sustains itself, and if a moderate weight be placed upon it, it will be all the firmer.
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