Three knives may be supported by their handles in the following manner: Place three glasses in a triangle, each side of which must be about the length of one of the knives. The blade of the first knife should rest on the blade of the second, by passing over it near to the point where the handle and blade are joined; the blade of the second passing in the same manner over the blade of the third, which is to be made to rest on the blade of the first. The handles being then carefully placed upon the glasses, a bridge is formed strong enough to bear a considerable weight.
To Balance a Coffee-Cup on the Point of a Knife
The articles necessary for the performance of this trick are very simple, a dinner-fork and an ordinary sized cork being all that are needed. Fix the cork firmly in the handle of the fork, then stick the fork into it so that two prongs shall be on each side of the cup handle, and slope the fork in such a way that its handle will come under the bottom of the cup. The heaviest weight being thus brought underneath, you can hold the cup on the point of a knife, if you very carefully find the exact place on which it will balance.
As the surface of the cup is usually glazed, the hand which holds the knife must not tremble, or the cup will slip off.
You may also obtain the same result by using two knives instead of a fork.
The Obstinate Cork
Take a small cork and ask some one to blow it into a fairly large sized, ordinary bottle that has a neck.
This seems to be quite an easy matter. The one who tries it will probably blow as hard as possible upon the little cork; but, instead of going into the bottle, as expected, it will simply fall down. The harder the puffs or blows, the more obstinate the cork will appear to be; and even if the effect of blowing gently be tried, it will be of no use; the cork will not go into the bottle, much to the amusement of those who are watching. The reason why the cork will not go in is this: The bottle being already full of air, when the cork is blown, more air will be forced into the bottle, and consequently the air inside will be greatly compressed and will simply force the cork back. The following is a simple way of overcoming the difficulty: Instead of trying to force the cork through the compressed air in the bottle, just the contrary should be tried, that is, some of the air should be sucked out of the bottle; this being done, the bottle will become partly emptied, and when the outside air rushes in to fill up the empty space, it will carry the cork with it to the bottom of the bottle.