8 



NATURE 



[April 22, 1922 



is considerable. I make no correction for it here. 

 Presumably we are dealing with an a-ray of the 

 same range as that which must have been concerned 

 in the genesis of the Yitterby haloes. 



This range, if taken as 0-005 mm., would correspond 

 to about I cm. in air at 15° C. The radioactive 

 element concerned, although associated with the 

 uranium family of elements in the Arendal mica, 

 cannot be a member of that family. This appears 

 ^rom the value which in such a case we must 

 ascribe to X. It would decay at a rate some billions 

 of times slower than uranium according to an ex- 

 terpolation on the Geiger-Nutall curve. Now the 

 ring in the Arendal mica must have been formed 

 since early Archaean time and from a nucleus of 

 point-like dimensions. 



From all this there seems good evidence that a 

 radioactive element exists (or formerly existed) 

 emitting an a-ray having a range of about one 

 centimetre in air. So far no evidence of its further 

 disintegration has been found. 



It seems probable that the development of the 

 small Yitterby halo-spheres represents a very con- 

 siderable period of time. It will be of interest to 

 see if similar evidence for what appears to be a very 

 long period of Earth-history, seemingly preceding 

 early Archaean time, will be forthcoming from 

 material found elsewhere. It is possible that this 

 period preceded the thermal conditions which gener- 

 ally prevailed during Archaean time and that the 

 survival of the evidence contained in the Yitterby 

 mica was due to local fortuitous conditions. These 

 haloes would, in that case, be a record carried from 

 one geological age to the next. 



I wonder am I justified in naming an element 

 from such evidence as I have found — the range of 



an a-ray 



I think it has been done before. 



If 



ever it is isolated I would ask the finder to call it 

 Hibemium after this beautiful but most unhappy 

 country. 



J. JOLY. 



Trinity College, Dublin, April 8. 



The Helmholtz Theory of Hearing. 



On a visit to the Cambridge Physiological Labora- 

 tory not long ago Dr. Hartridge" demonstrated an 

 apparatus of his design that showed the effect of a 

 repeated sinusoid vibration on a series of pendulums 

 of different periods. Each of a series of weights was 

 suspended from a horizontal bar. The strings were 

 all of different lengths ; each pendulum had thus a 

 different period. The horizontal bar was connected 

 with a wheel so that it could be moved back and 

 forth harmonically. 



When the wheel was started, all the pendulums 

 began to vibrate. As the wheel continued its rota- 

 tions, the pendulums gradually came to rest — except 

 one, namely, that one the natural period of which 

 corresponded with that of the rotating wheel. This 

 proved that with a continuous series of vibrations 

 only a pendulum with a harmonic period would be 

 maintained in vibration. It also proved that a single 

 vibration set all pendulums in vibration no matter 

 what natural periods they might have. Dr. Hartridge 

 has thus demonstrated that if the ear possesses a 

 series of resonating organs every one will respond to 

 the first vibration and will come to rest only when 

 this vibration has been several times repeated. 



When a person sings a glide from one note to 

 another, his voice produces vibrations that are all 

 different. Every one of these vibrations is the first 



NO. 2738, VOL. 109] 



of its kind, and at no moment is there a succession 

 of waves of the same period. Consequently at every 

 single vibration all the resonators in the ear are set 

 in vibration, and this vibration of all of them con-' 

 tinues throughout the glide. In speech the voice is 

 never still for an instant. Every vibration from the 

 larynx differs from the one before. Therefore in 

 perceiving speech every resonance organ of the ear 

 must act at every instant for every vibration of the 

 voice. 



Dr. Hartridge has given a complete and final proof 

 that, if the ear possesses a set of resonating organs, 

 they must all respond together for each new vibra- 

 tion ; as the changing tone of speech has a new 

 vibration at every instant, they must all respond 

 alike at every instant and for every tone. 



According to the Helmholtz theory each vibration 

 acts on a different resonator in the ear. In the 

 sliding tone always used in speech each single vibra- 

 tion must, according to Helmholtz, pick out a cor- 

 responding resonator. It is easy mathematically to 

 show that this cannot be true and that each single 

 vibration of the voice in speech must set all resonators 

 in action. Nobody seems to have thought of this, 

 and it has remained for Dr. Hartridge's highly in- 

 genious apparatus to kill finally the Helmholtz theory 

 of hearing. 



In the April number of the British Journal of 

 Psychology , Dr. Hartridge gives as the fundamental 

 reason for supporting the Helmholtz hypothesis that 

 the experiments described by him show that there 

 are resonators somewhere. As pointed out above, 

 they show exactly the opposite, namely, that there 

 cannot be any resonators anywhere. If there cannot 

 be any resonators, then the hypothesis that the ear 

 acts as a resonating apparatus becomes an impossible 

 one. 



E. W. Scripture. 



Boyle's Experiments on Capillarity. 



In Mr. Hardy's interesting " Historical Notes upon 

 Surface Energy and Forces of Short Range," Nature, 

 March 23, p. 375, he says that " Boyle tried, but 

 failed, to observe whether the (capillary) rise took 

 place in a vacuum." Boyle writes in Experiment 

 XXXV. of the " New Experiments Physico-Mechani- 

 cal " that after showing the capillary rise in open 

 air, " We tried indeed, by conveying a very slender 

 pipe and a small vessel of water into our engine 

 (air pump receiver), whether or no the exsuction 

 of the ambient air would assist us to find the cause 

 of the ascension we have been speaking of ; but 

 though we employed red wine instead of water, yet 

 we could scarcely perceive through so much glass, 

 as was interposed betwixt our eyes and the liquor, 

 what happened in a pipe so slender, that the redness 

 of the wine was scarcely sensible in it. But, as far 

 as we could discern, there happened no great altera- 

 tion to the liquor ; which seemed the less strange, 

 because the spring of that air, that might depress 

 the water in the pipe, was equally debilitated with 

 that, which remained to press upon the surface of 

 the water in the glass." Boyle was a very careful 

 and accurate experimenter, and he was trying to 

 find whether there was an alteration in the capillary 

 height in vacuo. His experiment was quite accurate 

 and is worthy of his great reputation, 



Sidney Skinner. 



South- Western Polytechnic Institute, Chelsea, 

 London, S.W., April 6. 



