Some Experiments with the Sthenometer: Evaluating Dr Joire’s Results

vintage psychic research tool

Diagram of a sthenometer.

Having been slammed by the ‘flu rather badly, I revisit a topic initially posted back in October, about some of the early tools of psychic researchers, with


By F. J. M. Stratton And P. Phillips.

In a paper in Les Annales des Sciences Psychiques (1904, p. 243) which also appeared in the Revue de I’Hypnotisme (Feb. 1905), Dr. P. Joire describes an instrument called the sthenometer; it consists of a light straw pointer suspended on a vertical needle-point and protected by a glass shade. When a hand is brought near the instrument at right angles to the pointer and with the finger-tips opposite to the end, the pointer is attracted towards the hand by varying amounts. Having observed a connection between the magnitude of this motion for the two hands and the nervous condition of the individual, Dr. Joire claims to have discovered a nervous force emanating from the body and causing this motion.

In order to test these statements of Dr. Joire we have carried out a number of experiments with a sthenometer kindly lent us by Mr. F. W. H. Hutchinson, of Cambridge, and we have come to the conclusion that the whole of the results may be very well explained as due to heat radiated from the hand. This idea was first strongly suggested by the marked lag between the placing of the hand in position and the commencement of the motion of the pointer. It was further supported by the following observations:

(1) If the hand was placed in direct contact with the glass, so that the glass was heated much more rapidly and to a higher temperature, the lag was very much smaller and the motion of the pointer more rapid and through a larger angle. In fact with the hand touching the glass and moved continually so as to always keep the finger-tips in position opposite the end of the pointer, the latter moved through over 90° in a minute.

(2) If a hot object, such as a heated poker, a spirit stove, a lighted match, or an electric lamp, was brought up, a large and rapid motion of the pointer towards the hot object was produced.

These results led us to repeat the experiments by which Dr. Joire claimed to have eliminated heat as a possible explanation of the motion produced. The deflection caused by a hand was observed first with and then without a thick screen of non-conducting material interposed, the position of the hand being the same in both cases. We used for our screen three or four thicknesses of an eiderdown quilt. The following were the results obtained:


With screen  Without screen.

-1°        +6°

+ 1/2°          +8°

+ 1°          +10 1/2°

+3/4°       +17°

The deflections obtained in the presence of the screen were on the whole such as might be expected if the heat from the hand slowly filtered through; no great importance can be attached to them, as such slight deflections are often caused by vibrations or air-draughts, to which the instrument is very sensitive. At any rate the screen almost entirely cut off the effect on the pointer, and this seems to show that the deflection obtained by Dr. Joire under similar conditions was spurious and to be explained by accidental causes.

To make the heat test more definite, experiments were tried with a six-inch Leslie’s cube filled with water heated to 40° C. The vertical sides of the cube were (1) polished, (2) painted white, (3) painted a deep cream, (4) painted black. When it was placed in somewhat the same position as the hand, the following deflections were obtained, each in five minutes:

(1) polished side, 3°.

(2) white side, 6 1/2°.

(3) deep-cream side, 13 1/2°.

(4) black side, 47°.

Thus the deflections increased largely with the amount of heat radiated from the side of the cube; 40° C. is slightly above the temperature of the blood, and it is interesting that the effect produced by the deep-cream side is of the same order as that produced by the hand. This same side, when the cube was filled with a mixture of ice and water, repelled the pointer through 6°, and we may mention here that among the many hands tested by us, only one showed any sign of repulsion, and then only through 1/2°.

Finally to establish the connection between the motion of the pointer produced by the hand and the heat radiated from it, the following deflections were observed:

(1) In the Sthenometer when the hand was placed at a fixed distance from it.

(2) Immediately afterwards in a galvanometer connected with a thermopile when the hand was placed at a fixed distance from the latter.

The following results were obtained with five different hands:

Deflexion in Sthenometer. Deflexion in Galvanometer.

10| 1/2°     2-4 cms.

12°       3 cms.

13°       3-9 cms

14 1/2°     4-7 cms
16 1/2°     5-5 cms

This shows that the deflection in the sthenometer increases with the amount of heat radiated from the hand and the correlation between the two sets of figures is as close as could be reasonably expected if heat is assumed to be the sole cause of the motion. We may suppose that the glass becomes heated and so sets up air convection currents setting the pointer in motion towards the heated spot.

To test this suggestion the pointer was suspended in a bell-jar which could be exhausted of air. At atmospheric pressure a hand brought near in the ordinary way gave a deflection of 14°. When the pressure was reduced to 1.1 cms. of mercury the same hand placed in the same position gave a deflection of certainly not more than 1/4°. This is conclusively in favour of the above suggestion.

There may of course be a relation between the heat radiated from the two hands and the nervous condition of the individual, and Dr. Joire’s criterion of the meaning of the results given by the sthenometer may still be of value. But our own experiments with twenty-one different individuals would not lead us to support his views. Quite a large proportion of apparently healthy undergraduates showed signs of hysteria, neurasthenia or nervous depression, according to Dr. Joire’s criterion, and one individual, apparently in normal good health all the time, in the course of twelve days ran through the whole series of nervous troubles indicated in Dr. Joire’s second paper. It has seemed to us that the effect produced by the two hands depended far more on the changes in the temperature of the hands induced by exercise or other causes than on variations in the general nervous state. In any case a thermopile would be a more reliable and sensitive instrument for testing this point than a sthenometer. And it might be well worth while for any one with facilities for studying neurasthenic patients to test Dr. Joire’s criterion with both instruments.

It might also be of interest to perform carefully some experiments on bodies of different material held for a time in the hand and then placed by the sthenometer. Dr. Joire in his latest paper (1) gives an account of some such experiments, but does not give sufficient details to substantiate his claim that the results could not be due to heat. He took no precautions to measure the amount of heat which would be radiated from the bodies after being held in the hand. This would depend on a good many circumstances, which are insufficiently or not at all dealt with, such as the nature of the surface, the material, the thickness, and the temperature, etc., of the body used. Dr. Joire’s results as described do not seem in any way inconsistent with our hypothesis.

We have tried a few rough experiments on the same lines, without anything occurring which could not be well explained by the radiation of heat stored up in a body while it was held in the hand. But the point might be worthy of a more detailed and quantitative study than we have so far been able to give to it.

In conclusion, reference may here perhaps be usefully given to a paper by Sir William Crookes (2), in which he gives an account of some careful researches into the rotation of a delicately suspended cylinder of ivory. He reached the conclusion that the motion was produced by molecular pressure caused by radiation and not by air-currents. The sthenometer, however, appears to belong rather to the class of instruments discussed in a note by Dr. Abraham Wallace and Mr. St. George Lane Fox in this Journal (Vol. VIII., p. 249, June, 1898). They showed the air currents, which produced the motion of a delicately suspended body under a bell-jar, by means of clouds of smoke. We can but support their claim that no instrument can contribute to our knowledge of “psychic force” which does not eliminate or duly account for the presence of the various forces well known to the physicist, and we submit that the sthenometer has failed to satisfy this test.

1 “The Storage of the Exteriorised Nervous Force in Various Bodies,” Annals of Psychical Science, July, 1906.

2 “On the supposed ‘New Force’ of M. J. Thore,” Philosophical Transactions of the Royal Society, Vol. 178, A. (1887).

SOURCE: Journal of the Society for Psychical Research, Volume 12 1906: pp 335-339

I hope to return to regular form soon.

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