Take an ordinary wooden matchbox, and remove the drawer holding the matches. In the center place a small coin, a cent will be the best for the experiment, the object of which is to make the coin fall into the interior without touching it. Tap lightly on that side of the box to which you desire the coin to come, until it rests upon the edge. [Illustration] Then slightly raise the end of the box whereon the coin rests, and lightly tap with the finger once more. At once the coin will fall into the box. The secret of the experiment is this: the taps on the box only move the box, while the coin retains its position by reason of its own inertia, until the edge of the box reaches it. The last tap knocks away the support, and the coin, obedient to the law of gravity, falls vertically into the interior of the box. This little experiment is easily performed, and extremely interesting when done neatly. To Cut a String With Your Hands. With a little practice, and some briskness of movement, you may be able to break a string of considerable thickness by proceeding as follows: Wind the string round your left hand, so as to make a loop, as shown in the figure. Pass it three or four times round the fingers to insure the solidity of the loop. Seize firmly the other end of the string with your right hand, around which you wind it three or four times, then give a brisk pull. The string will be clean cut at the junction of the loop in the left hand. [Illustration] When the knack is well acquired, one may break the string on two fingers only, by following always the same theory as above. The Rebound. On the neck of a bottle place a cork in an upright position. The cork must be large enough to rest on the neck without falling in. Now give a sharp fillip on the neck of the bottle, and you will see the cork fall, not on the other side of the bottle as most people expect, but forward in the direction of the hand giving the blow. This, again, is an illustration of the principle of inertia. A rapid blow tends to push the bottle from the cork before the movement is transmitted to the latter. Few people will execute this experiment properly the first time, for the instinctive fear to break the bottle and cut their fingers, will prevent them giving a blow sharp enough to make this experiment successfully at the first attempt; but with a little perseverance, the necessary degree of force will be gauged to a nicety. [Illustration] A Fiery Catapult. Take a match-box and place it upright edge-wise and place two matches in each side between the inner and outer box, heads up. They must be inserted deeply enough to stick firmly. Place a third match cross-wise between them and it will stay there by the pressure the latter exercises on them. Now light the middle of the horizontal match and wait. What do you think will happen? Ask the bystanders which will first catch fire? The natural conclusion they will draw will be the following.