The Magnetic Ring. Take a gold ring,—the more massive the better. Attach the ring to a silk thread about twelve inches long; fasten the other end of the thread around the nail-joint of your right forefinger, and let the ring hang about half an inch above the surface of the table, on which you rest your elbow to steady your hand. Hold your finger horizontally, with the thumb thrown back as far as possible from the rest of the hand.
If there be nothing on the table, the ring will soon become stationary. Then place some silver (say three half-dollars) immediately below it, when the ring will begin to oscillate backwards and forwards, to you and from you. Now bring your thumb in contact with your forefinger (or else suspend the ring from your thumb), and the oscillations will become transverse to their former swing. Or this may be effected by making a lady take hold of your disengaged hand. When the transverse motion is fairly established, let a gentleman take hold of the lady’s disengaged hand, and the ring will change back to its former course. These effects are produced by the aid of animal magnetic currents given forth by the hands of the experimenters.
To Tell the Hour of the Day or Night by a Suspended Quarter. Sling a quarter or a dime at the end of a piece of thread by means of a loop; then, resting your elbow upon a table, hold the other end of the thread between your forefinger and thumb, and thus suspend the coin in an empty goblet. Observe, your hand must be perfectly steady; and if you find it difficult to keep it in an immovable posture, it is useless to attempt the experiment. Premising that the quarter is properly suspended, you will find that, when it has recovered its equilibrium, it will for a moment be stationary; it will then, of its own accord and without the least agency from the person holding it, assume the action of a pendulum, vibrating from side to side of the glass, and after a few seconds will strike the hour nearest to the time of day. It is necessary to observe that the thread should lie over the pulse of the thumb, and this may in some measure account for the vibration of the quarter, but to what cause its striking the precise hour is to be traced remains unexplained; for it is no less astonishing than true that when it has struck the proper number its vibration ceases, it acquires a kind of rotary motion and finally becomes stationary as before.
The Spirit Calculator. A piece of paper and a pencil are handed to the audience, with a request that four different persons will each write down a row of four figures, one under the other, to form an addition sum. The paper is then given to a fifth person to add up the figures, but before he can call out the result the performer writes it down on a blackboard.
The secret lies in the fact that the performer is in possession of a piece of paper exactly the same in every detail as that handed to the audience, on which, previous to the entertainment, he has had four rows of figures written in different handwritings. In the course of the entertainment, all is fair and aboveboard until it comes to adding up the sum, when the performer, in the act of giving the paper to the fifth person, changes it for that of his own, with the total of which he is already acquainted. He has now only to run to the stage and write down the answer on the blackboard.
A more startling conclusion than the prosaic one above mentioned may be obtained by the use of sympathetic ink, composed of sulphuric acid and water, one part of the former to three of the latter. Writing done with this ink will be invisible until heat be applied, which will bring out the characters in jet black.
The performer, then, being provided with a piece of paper bearing the answer written with the invisible ink, gives a plate containing a little alcohol to the person adding up the sum, and asks him to set fire to the alcohol, first, however, taking careful note of the total. The prepared piece of paper is now held over the flames caused by igniting the alcohol on the plate, when the heat will bring out the answer, which is proved to be correct. The greatest care should always be exercised in producing any kind of flame.
The Square of Sixteen Numbers. Arrange the numbers from 1 to 16 in a square, so that the sum of the figures in any row, vertical, horizontal, or diagonal, will be 34.
| 16 | 3 | 2 | 13 |
| 5 | 10 | 11 | 8 |
| 9 | 6 | 7 | 12 |
| 4 | 15 | 14 | 1 |
The Square of Nine Digits. How may nine digits be arranged in a rectangular form so that the sum of any row, whether horizontal, vertical, or diagonal, shall equal 15?