8 4 4 



NA TURE 



[December 23, 1922 



Such radiations are frequently described by writers 

 on the occult sciences as being emitted by the human 

 body. For example, in the chapter on magnetism in 

 M. de Dubor's recently published " Mysteries of 

 Hypnosis," I read of a doctor who was making 

 magnetic passes over a lady. " The subject was 

 wearing a black dress, and the doctor had his back 

 to the light. Suddenly, in the semi-darkness which 

 surrounded him, he observed a greyish vapour, like 

 the fumes of a cigarette, issuing from the tips of his 

 fingers, and, with especial clearness, from the index 

 and the middle fingers. Moreover, the index fingers 

 of the two hands seemed to be united by a luminous 

 arc or semicircle. . . . Other persons, on the doctor's 

 invitation, drew near and observed the same pheno- 

 menon. . . . Then the room wasdarkened. . . . In the 

 darkness, twelve of the witnesses perceived nothing 

 at all, and the remaining six perceived only very 

 little." 



M. de Dubor and the whole occult school explain 

 the glow, or aura, seen round the hand as being due 

 to magnetic emanations from the body (using the 

 word magnetic in a superphysical sense"). They ap- 

 pear to think that the phenomenon is more rare than 

 it actually is, and do not treat the case of cardboard 

 hands. For the phenomenon as observed with these, 

 there would seem to be two possible alternative ex- 

 planations. One is, that the cardboard is occult card- 

 board, and the scissors hypermagnetic scissors, and 

 that I have unwittingly impregnated everything with 

 induced ectoplasmic activity. The other is that the 

 phenomenon is a retinal (and rational) one, which can 

 be observed whenever a white, or whitish, surface is 

 seen in a feeble light, the visual purple from the actual 

 retinal image diffusing into the neighbouring parts of 

 the retina. Accepting, for argument's sake, the latter 

 explanation (which accounts at once for the fact that 

 nothing is seen in the dark), the effect will be in- 

 tensified by the restless movement of the eye, which 

 undoubtedly takes place when objects are viewed in 

 unfavourable circumstances. 1 The eye shifts the 

 image into an unfatigued part of the retina, and the 

 after image persists as a feeble glow. Such pheno- 

 mena have been frequently described by Dr. Edridge- 

 Green in a variety of forms, and I do not claim any 

 particular originality for this prosaic explanation. 



But a further very interesting phenomenon can be 

 observed with the cardboard hand, which has not, I 

 believe, been described. If it be looked at fixedly, 

 the ends of the fingers will be seen to vanish inter- 

 mittently, now one, now the other, while the extended 

 thumb and little finger appear to move up and down, 

 producing somewhat the appearance of a hand opening 

 and shutting. The effect is very striking, and is 

 pleasantly diversified by the complete disappearance 

 of the hand at intervals. This is due either to retinal 

 fatigue, combined with eye movement, or else to the 

 ferro-forcificatory magnetism of the scissors, per- 

 meated as they must be with psychic influences and 

 what not. I must leave it to the readers of Nature 

 to repeat the experiments, and judge for themselves. 

 Seeing that the festive season (I understand that 

 this is the correct way to refer to Christmas) is upon 

 us, I venture to describe a third occult phenomenon, 

 somewhat analogous to that quoted by Dr. Edridge- 

 Green in Nature of December 9, p. 772. Two heads, 

 facing one another, are cut out of white cardboard in 

 profile, and observed in a very subdued light against 

 a black background as before. (My heads are about 

 two and a half inches in diameter, and the noses 

 about half an inch apart.) 1 !y a delicate manipula- 

 tion of the scissors one of the heads may be given 

 a feminine character, largely by providing it with 



1 See, e.g., Edridge-Green'> " Physiology "t Virion." (G. Bell and Sons.) 

 NO. 2773, VOL. I lo] 



back hair. On careful observation the heads will be 

 seen to approach and kiss repeatedly, separating with 

 rapturous amaze after each contact. Like the other 

 phenomena, including M. de Dubor's magnetic fluid, 

 this cannot be observed in the dark, nor, I may add, 

 even heard, in the case of the cardboard heads. 



All the phenomena seem to be observed even more 

 easily by myopic people than by myself. A morn- 

 ing's experiment has convinced me that with suitable 

 illumination and white cardboard a very creditable 

 scanct' can be arranged, including aurae, movements 

 and levitations, magnetic emanations, and ectoplasm. 

 This method involves no expense and no hymn sing- 

 ing. Even an atmosphere of reverence is not neces- 

 sary for the production of the phenomena, although, 

 I admit, the morning of my essay in the occult art 

 was a Sunday morning, which may have had some 

 favourable effect. E. N. da C. Andrade. : 



Artillery College, Woolwich, 

 I (ecember 1 1 . 



A Relativity Paradox. 



It is with great diffidence that I enter the relativity 

 controversy, since I know little or nothing of the 

 subject. Ignorance, however, is seldom a bar to 

 the expression of opinions. I understand that the 

 fundamental idea underlying the theory of rela- 

 tivitv is that no signal can be transmitted through 

 space at a greater speed than 

 the velocity of light. There 

 appears to me, however, to 

 be a method by which, in 

 theory, it might be done, and 

 since we have trains running 

 past embankments with half 

 the speed of light, and shells 

 with observers inside travel- 

 ling at even higher velocities, 

 perhaps my observer at A 

 (Fig. 1) may be allowed to 

 have two immensely long tri- 

 angles made of any suitable 

 material ; A signals to B by 

 sliding the two triangles to- 

 gether, one over the other, in 



the direction of the arrows ; the point X, where the 

 two sides intersect, moves towards the observer B, 

 who receives the signal when he observes the point of 

 intersection pass over him. If the angle at X is 10" 

 and the triangles are moved together at a speed of 

 ten miles a second (an absurdly small speed for a 

 relativist), the signal will be transmitted to B with 

 more than twice the speed of light. C. C. 



Is not "C. C." assuming that when A shifts his 

 triangles by tugging at their bases the apices in- 

 stantaneously start to move ? But the impulse 

 would traveffrom base to apex at a speed far less than 

 that of light, namely, the speed of elastic waves in the 

 material. After the lapse of sufficient time the two 

 triangles would move uniformly and as a whole ; 

 and the mechanism provides a good illustration of a 

 recognisable point moving much faster than light. 

 The relativist does not object to this, since the 

 motion of X does not then correspond to anything 

 coming within the definition of a signal. The time 

 of signalling from A to B must be reckoned from the 

 moment that A gives the impulse to the mechanism. 

 A. S. Eddington. 



Observatory, Cambridge. 



