August 25, 1921] 



NATURE 



811 



p. 15. My knowledge of Stempell's paper was de- 

 rived from an abstract in which the osmotic aspect 

 was chiefly emphasised. On reference to the 

 original I find that this part of the process is ob- 

 scured by a number of complicated subsidiary hypo- 

 theses. W. M. Bayuss. 

 Univ'ersity College, London. 



A Correction. 



Some months ago Sir Ray Lankester was good 

 enough. to write to me in regard to the statement in 

 my '"System of Animate Nature " (1920) that he had 

 spoken of evolution as "a chapter of accidents." He 

 asked me to verify the quotation, and I thought I 

 had* only to turn to my book-shelves for a minute to 

 find the passage. But in spite of some months of 

 very agreeable and profitable re-reading of Sir Ray 

 Lankester's writings, I have failed to verify the quota- 

 tion, and the only thing to do is to apologise. Per- 

 haps I should have seen that the phrase I . ascribea 

 to Sir Ray Lankester was inconsistent with such sen- 

 tences as these: — "Thus then it appears that the 

 conclusion that Man is a part of Nature is by no 

 means equivalent to asserting that he has originated 

 by ' blind chance ' ; it is, in fact, a specific assertion 

 that he is the predestined outcome of an orderly, and 

 to a large extent 'perceptible,' mechanism" ("The 

 Kingdom of Man," p. 9); and "They [the mental 

 qualities which have evolved in Man] justify the view 

 that ]\Ian forms a new departure in the gradual un- 

 folding of Nature's predestined scheme " (op. cit., 

 p. 25). 



I yield to no one in my appreciation of the services 

 which- Sir Ray Lankester has rendered to zoology 

 and biology, and I can only express my regret that in 

 a busy life 1 made a mistake which amounts to an 

 unintentional misrepresentation. 



J. Arthur Thomson-. 



Natural History Department, Marischal 



College, University of Aberdeen, August 16. 



Wrightson's Hypothesis of Audition. 



The hypothesis advanced by the late Sir Thomas 

 Wrightson in his book " An Enquiry into the 

 Analytical Mechanism of the Internal Ear " has, it 

 would seem, received such wide acceptance that the 

 following comments upon it may be of interest. 



Wrightson suggested that the appreciation by the 

 ear of the constituent notes in a musical chord is 

 due to the recognition and measurement by the brain 

 of certain time intervals, which occur between the 

 changes in motion of the air when it is transmitting 

 music. In proof of this suggestion Wrightson gives 

 graphic examples. First he takes two simple sine 

 curves representing two musical notes, and from 

 them he obtains a third curve which shows the 

 motion of the air when both notes are sounding to- 

 gether. On this compound curve he marks distances 

 between crests, troughs, and crossing points which 

 are equal to the wave-lengths of the two separate 

 notes. 



From the identity of these distances Wrightson con- 

 cludes that when the observer appreciates the con- 

 stituent notes in a chord he does so by recognising the 

 existence of these time relationships. 



I find, however, that this proof loses its value, 

 since it can be shown by trial that purely arbitrary 

 wave-lengths are also represented in the compound 

 curve as frequently as are those of the notes actually 

 present. 



It is scarcely possible, therefore, to accept Wright- 

 son's explanation of the power of analysis possessed 

 by the ear, since, all wave-lengths being equally repre- 

 NO. 2704, VOL. 107] 



sented, there is no criterion by which the right notes 

 can be recognised and the arbitrary ones excluded. 



This criticism, considered in conjunction with that 

 of Boring and Titchener [American Journal of 

 Psychology, vol. xxxi., 1920, pp. 101-13), would seem 

 to take from Wrightson's theory almost all the essen- 

 tial features which individualise it from the older 

 telephone theory of Rutherford. H. Hartridge. 



The Generation of Heath-fires. 



It is the general practice to attribute the heath- 

 fires which have been so common of late to the care- 

 less dropping of matches or to the camp-fires of 

 picnic-parties. But this is not always the cause. 

 An instance came under my notice during the late 

 hot weather which seems to be worth recording. I 

 was walking along one of the ridges at Finchamp- 

 stead, Berks, and to the south was a fairly steep 

 slope of peaty heath land, giving rise here and there 

 to clumps of bracken, but exposed each day to the 

 sun's rays for many hours at a time. Noticing 

 some smoke emerging from the soil, I turned down 

 the slope to stamp out a possible fire, and I found 

 that as soon as it was put out in one place it emerged 

 elsewhere, a foot or so away. My companion and 

 I repeated the process in many places, but soon 

 we saw that the smoke was emerging from a hun- 

 dred places, and our efforts were useless. Smoke 

 was rising out of the peaty soil over an area of 

 at least a quarter of a square mile, and another 

 hour of the sun's heat might have been sufficient 

 to result in the place breaking into flame. 



From a note in Nature of Januar\' 27 last, p. 704, 

 in regard to the spontaneous burning of coal-seams 

 in the United States, I see that the fine dust of 

 lignite may ignite at 150° C, and I suggest that in 

 the case in point the finely divided carbonaceous soil 

 may have been undergoing such changes under the 

 heat of the sun, which may have brought up the tem- 

 perature to something approaching this. Anyway, 

 here was a considerable ^rea smoking under the 

 intense heat, and ignition could not have been far 

 off. Edwd. a. Martin. 



South Norwood, S.E., August 13. 



Cornalith. 



In the Bulletin of Agricultural Intelligence 

 issued by the International Institute of Agriculture, 

 just to hand, there is a precis of an article in the 

 Annales de Gembloux under the heading " Plastic 

 Materials with a Casein Basis : Galalith and Corna- 

 lith." The latter word is not in the N.E.D. or in 

 the recently published •' Dictionary of Scientific 

 Terms." Galalith, or "milk-stone," is well known, 

 and cornalith will be "horn-stone." The first sen- 

 tence in this precis reads : " Galalith and cornalith, 

 two substances made from casein that has been 

 treated with formalin, are produced now in various 

 countries, especially in France, where there are 

 already several factories." 



It is stated that, in order to diminish the cost of 

 opaque articles made from casein treated with formal- 

 dehyde, the raw material is sometimes mixed with 

 the refuse of horns, horsehair, and other nitro- 

 genous matter. When this is done is it called "corna- 

 lith," and, if so, does the name or term correctly 

 describe the material? 



It is also stated that attempts have been made to 

 use vegetable casein extracted from soya beans, as 

 being less expensive than casein obtained from milk. 

 Has this been successfully accomplished, and, if so, 

 can the resulting plastic material be called "galalith," 

 or is some other term used ? R. Hedger Wallace. 



August 16. 



