Metapsychical Phenomena: Methods and Observations

by J. Maxwell

I will add that every one present can and does hear them. Let me recall to mind what I said about the raps I heard in railway refreshment rooms, restaurants, and other public places. All who were in the same room showed, by their demeanour, that they too heard the raps. This circumstance suffices to exclude the hypothesis of hallucination. I propose registering these raps in a phonograph; this will be the experimentum crucis as far as their objectivity is concerned.

I have no manner of doubt whatsoever upon the authenticity of raps, a phenomenon I have heard so frequently, and under such diverse and excellent conditions. I have also taken care to study the different ways of simulating raps,—and these are indeed manifold.

The simplest and most perfect method is to gently glide—an imperceptible movement—the finger-tips along the table. The results are better when the finger is dry, when the natural grease has been previously removed by turpentine or benzine: resin is good, but leaves traces. Under these conditions, slight but clear raps may be obtained. The movement of the finger is so slow, that, unless forewarned, no one can discover it; but, with attentive observation, a slight vibration of the finger may be perceived when the raps burst forth. They can also be simulated with the finger-nails, but this process is easy to unmask.

The trickster finds greater security in darkness, where he has resources other than those just mentioned. In obscurity he can easily imitate the raps which resound on the floor; e.g. he can produce dull raps by skilfully striking his foot against the legs of the table or on the floor; he can simulate the sharp, quick raps by allowing his boot to glide slowly along the feet of the table or chair.

Raps are also very easily simulated by a gentle rubbing of clothing or linen, especially shirt-cuffs. We should beware of this, for raps can thus be produced by slow unconscious movements, and the good faith of the experimenters may be involuntarily taken by surprise.

There is yet another way of obtaining fraudulent raps; this is by leaning more or less heavily on the table. When the top of the table is thin, or when the table is badly put together, or the parts have too much play, the variations of the pressure of the hand determine noises which greatly resemble raps.

Lastly, I have sometimes observed raps produced in a way which should be made known. Some people, by leaning the foot in a certain way, and by contracting the muscles of the leg, can imitate raps on the ground. This fact has been indicated especially in connection with the sinews of the musculus peronaeus longus. I observed a medical student, an incorrigible cheat and neurotic, who obtained sounds very similar to authentic raps by leaning his elbow on the table, and making certain movements with his shoulder. There are also some people who can make their joints crack at will.

But force of habit soon teaches how to ferret out fraud, when working in daylight or with good artificial light. Besides, the tonality of authentic raps is characteristic, and the method of simulation indicated at the beginning of these remarks, i.e. finger-gliding, is the only one able to reproduce some of the raps with even a fair amount of exactness.

It does not seem to me to be possible to simulate raps on the table, when they are produced without contact. It is easy to localise them, and auscultation of the table enables us even to perceive the vibrations of the wood. Precautions, easily taken, enable us to make sure of the absence of contact and communication between the experimenters and the table.

To sum up, I am certain—as far as it is reasonably possible to be certain of anything in such a matter—that knockings of variable rhythm and tonality are heard in the presence of certain persons—knockings or ‘raps’ which cannot be explained by any known process. They are heard at diverse distances; they often seem to obey the expressed wishes of the sitters, and to manifest a certain independent intelligence. On the other hand, their production appears to be intimately connected with the nerve-energy of the medium and the sitters.