i.Y 9, 19 1 9] 



NATURE 



365 



1. inn wind did no1 affect Scotland ami noi 

 h, Paris, and Bi ussels i - 

 lin 1I1.' i asi of Pai i- i xti ndi ; "- middli ol 



ihr . ighteenrh . i ntui \ i disi i I hruary 



maxin on this occasion. 



At high of this remarkable heat- 



wave would seem ti ha hi i tstward 



advance, f..r at Davos Pl.it/. at an altitude of more 

 than 5000 ft., although the unprecedented February 

 temperature of 53 was reached on the 10th, il 

 not until the 15th that the very extraordinary winter 

 maximum of 63° was attained, and the same level 

 was touched on the 19th. S lal was the 



warmth that the average maximum for the six days, 

 15th 20th, was as high as 6i°, only one day being 

 below 60°. Within a few days of each other Montana 

 and Switzerland, in about the same latitude and at 

 about the ton, had temperatures differing 



•4 , from -6i° in a N.W. land-wind to +63 

 in a SAW sea-wind. 



How are we to account for the noticeable accession 

 of heat which these observations show- takes place as 

 the air spreads across the land further and furthei 

 away from what we regard as the seat of origin of 

 the warmth? Thus far, the only suggestion I have 

 received has been that perhaps it will prove to be of 

 1 jhn character — a descending current. There are 

 difficulties in the way of accepting this view. In the 

 first place, our south-westerly winds are ascending 

 - nding currents. We might be able 

 to show that winds from the Atlantic crossing moun- 

 tainous western Scotland are of the Fohn character on 

 reaching the east coast, but it is scarcely likely thai 

 a Scotch Fohn would bring to Aberdeen a February 

 temperature of 64 (more than 20 above the normal), 

 as on the 22nd in 1897. Such eminences as exist in 



NO. 2567, VOL. I02] 



the south ari too ndward and of too 



moderate altitudes to pn , 1 ;,, Londoii 



and the Eastern Counties, and across northern 

 France, Belgium, and Prussia. The Daw., Plat 

 perience does not supp irl the Fohn argument. It 

 should be borne in mind thai the phenomenon with 



liieh we are now dealing manifests itself a1 sea-level 

 on the extreme western coasts before any high land 

 I, and thenceforward there is a' progressive 

 ssion id temperature, regardless of mountain and 

 valley, sunshine and dullness, rainfall and drvness, 

 thus placing th. subject on a very different footing 

 from that of the Fohn. 



Now that the upper-air conditions are being so 

 ly observed, daily and almost hourly, it should 

 be possible at no distant date to accumulate sufficient 

 evidence to make a special investigation of the cir- 

 cumstances, above and below, which combine to pro- 

 dui e the temperature effects described above, and thus 

 i" .liable us to arrive at the correct explanation of 

 their causation and to predict their occurrence. 



.) The Grove, Isleworth. Hy. Harries. 



The Perception of Sound. 



Before the discussion on the physiology of the 

 internal ear is closed, it might be well to direct atten- 

 tion to a point in connection with the supposed neces- 

 sity of the auditory nerve transmitting the very large 

 number of impulses corresponding with the vibrations 

 constituting musical tones. 



Although the pitch of a particular tone is, sav, 

 640 d.v. per second, it is not necessary that, in order 

 to recognise, it, we should listen to that tone for a 

 whole second of time. Prof. McKendrick many vears 

 ago demonstrated that wo could recognise as distinct 

 from its predecessor and successor a note in a musical 

 composition if it were listened to for only i/64th of a 

 second. In such a case this would mean that onlv 

 ten condensations would affect the organ of Corti, 

 and presumably only ten nerve-impulses ascend the 

 auditory nerve. Prof. McKendrick, with whom it was 

 my privilege to be associated at that time, studied 

 the surface of the wax-cylinder records of musical 

 .-.itions recorded for reproduction by the phono- 

 graph. 



Since the speed of rotation of the cylinder was 

 known, the number of impressions in the wax corre- 

 sponding with each of a series of tones could be ascer- 

 tained; and it was found that, in order to recognise 

 any given tone, it was only necessary to " hear " 

 that tone for not longer than i/64th of a second. 

 If I remember correctly, a shorter period still was 

 in some cases demonstrated to be sufficient. 



Now if, say, i/iooth of a second is long enough, 

 it is clear that the hearing of quite high tones could 

 1 cted by a comparatively small number of vibra- 

 tions or disturbances in the internal ear and of sub- 

 sequent impulses in the nerve. 



A tone of 2000 d.v. per second could be recognised 

 by 20 impulses, and one of 10,000 pitch by 100, and 

 on. Apparently the auditory nerve is competent to 

 transmit individual impulses of that order of fre- 

 quency. 



It seems to me that attention to this point will make 



iroblem of hearing rather simpler than at first it 



appears by removing the necessity for believing that, 



in order to appreciate a note of a given pitch, we 



require to have the auditory nerve transmitting the 



large number of impulses corresponding with the large 



1 1 if vibrations which, according to physicists, 



i - the pitch or number per second of that note. In 



- ords the different tones in a musical com- 



p.>-iiiun follow one another with such rapidity that 



